Resource: Studies on Myocarditis and COVID-19 Vaccination

Links to studies on COVID-19 vaccination and myocarditis.

9/17/2023

Updated:

9/19/2023

0:00

This page includes links to studies on COVID-19 vaccination and myocarditis, a form of heart inflammation, and/or pericarditis, a related condition.

March 2021

March 20 Spain Case report of 39-year-old male doctor who experienced myocarditis after first dose of Pfizer vaccine. Tested negative for COVID-19. Researchers: "It seems reasonable to associate the clinical picture developed by this patient with an adverse reaction to the BNT162b2 vaccine against COVID-19."

March 31 Italy Report of healthy 56-year-old man who experienced myocarditis after second dose of Pfizer's vaccine.

April 2021

April 17 UK, etc. (later peer-reviewed) Base (pre-pandemic) rates of myocarditis and other countries presented.

April 29 Israel Case series of two patients with pericarditis after COVID-19 vaccination.

May 2021

May 18 US Report of 24-year-old man who experienced myocarditis after COVID-19 vaccination. Researchers: "Our case report raises concern that myocarditis is a rare side effect of COVID-19 vaccine."

June 2021:

June 4 US Series of seven previously healthy males aged 19 or younger with myocarditis after COVID-19 vaccination. Doctors ruled out COVID-19 and MIS-C. Researchers: Symptoms resolved "rapidly."

Companion editorial from the American Academy of Pediatrics: "Although the authors are quick to point out that a causal relationship between vaccination and myocarditis has not been established, the temporal association of these cases with vaccination as well as the striking similarity in the clinical and laboratory presentations raise the possibility for such a relationship."

June 8 Italy, Germany Case report of 30-year-old man with myocarditis after COVID-19 vaccination, with other causes ruled out.

June 10 US Series of four patients, including two students, with myocarditis shortly after COVID-19 vaccination.

June 14 US Case report of 24-year-old man with myocarditis after second Pfizer dose. Tested negative for viruses.

June 16 US Case series of six previously healthy males with no signs of infectious illness who developed chest pain within four days of their second shot. Imaging confirmed myocarditis.

US Series of four myocarditis patients, two of whom did not have COVID-19, following COVID-19 vaccination.

US, Italy, etc. Eight "otherwise healthy males" as young as 21 diagnosed with myocarditis after Pfizer or Moderna vaccination.

US Seven patients suffer myocarditis after COVID-19 vaccination. Some had prior COVID-19.

US Report of previously healthy 52-year-old man with myocarditis after second dose of Moderna's vaccine.

US Case report of a previously healthy 16-year-old male hospitalized with myopericarditis after second dose of Pfizer's vaccine.

Qatar Report of a 37-year-old man with myocarditis after second dose of Pfizer's vaccine. Researchers: "Vaccine-induced myocarditis is the most likely diagnosis in our patient."

June 17 US Two young previously healthy adults hospitalized with myocarditis after Moderna vaccination.

June 22 US 17-year-old male with MRI-confirmed myocarditis after receipt of second Pfizer dose. Researchers: "This case highlights the possibility that the COVID-19 mRNA vaccine may trigger recurrent acute myocarditis in children and adolescents who have had a previous episode of acute myocarditis."

June 26 France Analysis of 214 reports of myocarditis after COVID-19 vaccination concludes the Pfizer and Moderna vaccines are "significantly associated" with the inflammation.

June 28 US Two adolescent males suffer myocarditis after Pfizer vaccination.

June 29 Italy Case report of a previously healthy 20-year-old male with myocarditis after Pfizer vaccination and, earlier, COVID-19.

US Four patients with myocarditis after COVID-19 vaccination at Duke University Medical Center between Feb. 1 and April 30, 2021. Researchers: "It is possible that these 4 cases of acute myocarditis represent a rare, potential adverse event linked to mRNA COVID-19 vaccination."

US military Series of 23 people, including 22 previously healthy military members, with myocarditis following receipt of an mRNA COVID-19 vaccine. Seven still have symptoms.

CDC editorial On recent cases: "The striking clinical similarities in the presentations of these patients, their recent vaccination with an mRNA-based COVID-19 vaccine, and the lack of any alternative etiologies for acute myocarditis suggest an association with immunization."

July 2021:

Spain Case report of postvaccination myocarditis patient.

July 3 US Thirteen patients aged 12 to 17 with evidence of myopericarditis within 1 week of second dose of Pfizer's vaccine. Imaged using cardiovascular magnetic resonance (CMR). Researchers: "Although the symptoms resolved rapidly in all patients, their CMR findings indicate the potential for myocardial fibrosis and unknown long-term impact."

US Report of 67-year-old man who experienced heart failure after second dose of Moderna's vaccine. Tested negative for COVID-19 and influenza.

July 6 US (CDC) Of 484 myocarditis cases among people under 30 reported to the U.S. Vaccine Adverse Event Reporting System (VAERS) from May 1 to June 11, 323 were confirmed by investigators to be probable or confirmed cases. Researchers: "Follow-up is ongoing to identify and understand longer-term outcomes after myocarditis occurring after COVID-19 vaccination."

July 10 Korea 22-year-old man who experienced chest pain five days after receiving first Pfizer dose died 7 hours later. Researchers: "The primary cause of death was determined to be myocarditis, causally-associated with the BNT162b2 vaccine."

US, etc. Case report of 70-year-old woman with myocarditis after Johnson & Johnson vaccination.

July 12 US Meta-analysis on case reports.

July 14 Canada 34-year-old previously healthy man hospitalized after second dose of Moderna's vaccine. Symptoms included heart failure. Discharged after nine days.

July 16 Italy Report of 29-year-old man who suffered recurrent acute myocarditis after first dose of Moderna's vaccine.

July 18 US Cross-sectional study of 29 published cases of acute myopericarditis following mRNA COVID-19 vaccination.

July 20 US Cardiac MRI imaging from five patients with postvaccination myocarditis in early 2021.

July 24 Italy Report of 24-year-old nurse with myocarditis after second dose of Pfizer's vaccine. Tests ruled out COVID-19 and other viruses. Discharged after one week.

July 23 Qatar Previously healthy 29-year-old female presented to emergency room with perimyocarditis who experienced multi-organ failure. Researchers: "Most of the cases reported by the CDC had an uncomplicated hospital outcome and recovered fully unlike our patient who became very sick. This points to a possibility of increased reactogenicity in some patients due to COVID-19 vaccination"

July 25 Italy Case report of a 21-year-old male health care worker with myocarditis following second dose of Pfizer's vaccine.

July 26 US Series of previously healthy young males hospitalized with myocarditis after second Pfizer doses.

US Query of local health care database for myopericarditis patients aged 16 to 25 between Jan. 1 and May 20, 2021, identifies eight patients with myocarditis within eight days of vaccination.

July 30 US Cardiac MRIs on 15 of 16 children with myopericarditis after COVID-19 vaccination returned with abnormal results. Researchers: "The long-term impact of myopericardial inflammation after COVID-19 mRNA vaccine, especially in those with extensive myocardial involvement on CMR, remains unknown and needs to be systematically evaluated."

US (CDC) Review of 14 reports of death after vaccination showed one was due to heart failure, a symptom of myocarditis. Six had unknown causes or were pending further records.

July 31 Australia Australian health authorities detail 50 reports of suspected myocarditis and/or pericarditis following COVID-19 vaccination.

Poland 21-year-old man hospitalized with myocarditis after first dose of Pfizer vaccination.

Germany Series of three patients with myocarditis after receiving COVID-19 vaccination. Researchers: "Regarding current discussions addressing the risk–benefit ratio of COVID-19 vaccination of children and teenagers, vaccination-associated adverse effects—including autoimmune myocarditis—need to be considered carefully, since young people are at a very low risk for severe COVID-19 infection even without vaccination."

August 2021:

Aug. 2 Italy Report of a 56-year-old man who experienced myocarditis after first dose of Pfizer's vaccine, and four months after a COVID-19 infection. Researchers: "At the present time the benefits of Covid-19 vaccination significantly exceed possible risks."

Aug. 3 Germany Previously healthy 15-year-old boy hospitalized for seven days with myocarditis after second dose of Pfizer vaccine.

Aug. 4 US Case report of 44-year-old man hospitalized after receiving second dose of Moderna vaccine.

US Previously healthy 22-year-old man, with exception of mild case of COVID-19 six months prior, hospitalized three days after receiving first dose of Moderna's vaccine.

US Review of electronic medical records from 40 hospitals identifies 57 people who had vaccine-related myocarditis or pericarditis. Fourteen had not seen full resolution of problems as of last followup.

Aug. 6 South Korea Report of 24-year-old male hospitalized with acute myocarditis after second dose of Pfizer's vaccine. Researchers: "Although severe serious acute myocarditis following COVID-19 vaccination has been rarely reported, rapid surveillance such as cardiac markers, electrocardiography, or cardiac imaging should be required for its early diagnosis in patients with chest discomfort within one week following vaccination."

Aug. 8 Canada Framework for health care providers to assess suspected and confirmed cases of myocarditis following COVID-19 vaccination.

Aug. 9 US Four patients, aged 20 to 30, with myocarditis within four days of receiving mRNA COVID-19 vaccines.

Germany Case report of 28-year-old man hospitalized nine days after receiving Pfizer's vaccine. Non-vaccine causes ruled out.

Aug. 10 US (CDC) New risk-benefit analysis comparing benefits (numbers of COVID-19 cases and severe outcomes prevented) to risks (myocarditis only). For 18 to 29-year-old males per million second doses administered, for the next 120 days, 300 estimated hospitalizations and three deaths prevented versus 22 to 27 cases of myocarditis caused.

US Case series of 15 children younger than 19 hospitalized at Boston Children’s Hospital with myocarditis within 30 days of receiving a Pfizer dose between May 1 and July 15, 2021. Four patients had persistent symptoms.

Aug. 13 India A 33-year-old neurologist who developed myocarditis symptoms after first COVAXIN dose.

Aug. 16 Hong Kong Recommends rest for one week after COVID-19 vaccination and says benefits of vaccination outweigh the risks.

US Case report of 27-year-old male hospitalized with myocarditis after second dose of Pfizer vaccine.

US Report of previously healthy 33-year-old with myocarditis after receiving Johnson & Johnson's vaccine.

Aug. 17 US Series of two patients hospitalized after Pfizer vaccination. One died following cardiac shock and multi-organ failure. Family declined autopsy request. Researchers: "These cases identify the need for awareness of a potential, albeit extremely rare, link of BNT162b2 mRNA COVID-19 vaccination associated with fulminant myocarditis."

Aug 18 US Case report of two patients hospitalized with myocarditis after COVID-19 vaccination. One died. No non-vaccine causes were identified.

Hong Kong Mice suffer myopericarditis after receiving Pfizer's vaccine.

Aug. 19 Germany German Paul-Ehrlich-Institut lists 393 cases of pericarditis or myocarditis after Pfizer vaccination and 49 cases after Moderna vaccination.

Aug. 25 Israel Data from the largest health care organization in Israel show vaccination was strongly associated with an elevated risk of myocarditis.

Israel Eight patients hospitalized between February and April 2021 with suspected myocarditis after receiving a second Pfizer dose.

Aug. 27 Italy Suggests discouraging COVID-19 vaccination in patients with elevated troponin levels for at least six months, and in patients who experienced myocarditis after their first dose.

September 2021

Sept. 1 China Analysis of published trials and VAERS reports notes more than 1,600 reports of postvaccination myocarditis and pericarditis have been filed.

Italy, US, etc. Review of published reports claims all patients were discharged, excluding multiple patients that died.

Sept. 3 US (CDC) Reported postvaccination myocarditis is calculated as 565.9 events per one million person-years among males aged 12 to 39.

Sept. 4 Israeli military Series of seven male patients who suffered myocarditis within one week of receiving a second dose of Pfizer's vaccine.

Sept. 6 Germany Previously healthy 40-year-old man hospitalized with biopsy-confirmed myocarditis after first dose of COVID-19 vaccination. Discharged after four days. Cardiac MRI eight days later showed persistent problems.

Sept. 7 US A 62-year-old female died with myocarditis after receiving Johnson & Johnson vaccine. Researchers: "This case suggests a potential relationship between the viral vector COVID-19 vaccine and the patient’s lymphohistiocytic myocarditis resulting in severe biventricular cardiomyopathy and death."

Sept. 8 US (later peer-reviewed) VAERS review for adolescents aged 12 to 17 showed rates of cardiac adverse events following COVID-19 vaccination higher than COVID-19 hospitalization risk.

Sept. 9 US Case series of five male patients who experienced acute myocarditis within 72 hours of receiving a mRNA vaccine. Tested negative for COVID-19. Some had other viruses ruled out.

Italy Report of 45-year-old previously healthy male with myocarditis and shock after COVID-19 vaccination.

Sept. 11 US Case report of a 66-year-old man who began experiencing symptoms three months after second dose of Pfizer's vaccine. Resolved within 48 hours. Researchers: "Although causality could not be established, there was no other identifiable cause to explain the occurrence of acute myocarditis. The present case report provides new evidence regarding possible subacute to late-onset of myocarditis post-COVID-19 vaccine."

Sept. 14 US Case series of six previously healthy men who suffered severe chest pain and myocarditis within four days of a second dose of mRNA vaccination.

US Patients hospitalized with myocarditis after receiving mRNA vaccines. Two had prior COVID-19.

US Series of 11 patients with myocarditis after COVID-19 vaccination.

Sept. 16 Israel Data from health care organization show 48 cases of myocarditis or pericarditis after COVID-19 vaccination compared to 24 in the unvaccinated.

Sept. 18 Germany Previously healthy 20-year-old man suffered myocarditis 12 hours after his first dose of Moderna's vaccine.

Sept. 20 US Two male teenagers experienced acute myopericarditis after receiving Pfizer's vaccine. One admitted to pediatric intensive care unit.

US Series of two young males hospitalized within days of mRNA vaccination. Tested negative for COVID-19 and had no history of COVID-19.

Sept. 21 Japan Two men with myocarditis after Moderna vaccination.

US Editorial says that while VAERS "is subject to bias, a clear signal for vaccine associated myocarditis has emerged."

Sept. 22 US Case report of a previously healthy 29-year-old man hospitalized several days after receiving a second dose of Pfizer's vaccine.

Sept. 24 UK A 16-year-old male presented with "severe, stabbing chest pain" and fever three days after first Pfizer dose. Discharged after several days. Researchers: "Given the relatively small clinical benefit of a second dose of vaccine for someone of his demographic compared with the potential risk of myocarditis recurrence, he has been advised against a further dose at this stage."

Ireland Case report of 66-year-old with myocarditis after COVID-19 vaccination.

Sept. 26 US Case report of an otherwise healthy 17-year-old male with myocarditis after receiving Pfizer's vaccine.

Sept. 30 US Previously healthy 16-year-old female hospitalized after second dose of Pfizer's vaccine.

Germany Postmortem investigations of 18 vaccinated people, with full autopsies and other procedures. One person, a 65-year-old man, was found to have died of myocarditis after receiving a Pfizer dose.

Japan Case report of a previously healthy 49-year-old man hospitalized for 15 days with myocarditis after receiving second dose of Pfizer's vaccine.

Iran Report of 70-year-old man diagnosed with vaccine-induced myocarditis after receiving first AstraZeneca shot. Researchers: "This case ... confirms that myocarditis is a complication of COVID-19 vaccine."

October 2021:

Oct. 1 Italy Previously healthy 54-year-old woman with pericarditis after second dose of Pfizer vaccination.

Israel Series of seven patients (aged 16 to 18) from three pediatric medical centers hospitalized with myocarditis after receiving Pfizer's vaccine.

South Korea Case report of previously healthy 29-year-old male serving in the army who experienced chest pain after second dose of Pfizer's vaccine.

Oct. 2 US Report of 22-year-old female hospitalized after receiving second Moderna vaccine dose.

Oct. 3 Japan A 20-year-old woman with biopsy-confirmed acute myocarditis after second dose of Moderna's vaccine.

Oct. 4 US Analysis of Kaiser Permanente Southern California members aged 18 and older who received at least one dose of an mRNA shot between Dec. 14, 2020, and July 20, 2021, and hospitalized within 10 days, with a discharge diagnosis of myocarditis, identified 15 myocarditis cases.

US Editorial says identification of postvaccination myocarditis cases "does not change clinical decision-making."

Oct. 6 Israel Review of myocarditis cases appearing in nationwide surveillance through May 31, 2021, identifies 182 following COVID-19 vaccination. One patient, a 22-year-old, died.

Israel Analysis of cases among people 16 and older vaccinated from Dec. 20, 2020, to May 24, 2021, and enrolled in Clalit Health Services.

Oct. 11 Switzerland Swiss Society of Paediatric Cardiology position paper says "very low risk" of myocarditis and pericarditis "should not discourage vaccination."

Oct. 12 Spain A 28-year-old male without COVID-19 hospitalized with myocarditis two weeks after receiving second Pfizer dose. Echocardiography showed abnormalities two months later.

Oct. 15 Jordan, US Analysis of VAERS reports that includes suggestion to lengthen time between first and second doses.

UK Case series of elderly people with "probable vaccination-induced cardiac conduction disturbances" following COVID-19 vaccination.

Oct. 18 Saudi Arabia Case report of previously healthy 18-year-old hospitalized after second dose of Pfizer's vaccine.

Oct. 19 France Report of 19-year-old man hospitalized three days after receiving Pfizer's booster. Acute myocarditis confirmed by cMRI.

US Young males with myocarditis after receiving an mRNA shot. All were discharged with beta blockers and exercise restrictions.

Oct. 21 Brazil Case report of 47-year-old who received two doses of a COVID-19 vaccine, experienced COVID-19 reinfection, and suffered severe heart failure from myocarditis.

US A 32-year-old man hospitalized after receiving Moderna's vaccine. Tested positive for COVID-19.

US Case report of previously healthy 18-year-old with pericarditis after first Pfizer dose.

Oct. 26 France Narrative review describes myocarditis incidence following mRNA vaccination as rare.

Oct. 27 US Some patients with myocarditis after COVID-19 vaccination experienced persistent symptoms following hospital discharge.

Israel Stratification of earlier study. Shows five cases of myocarditis in vaccinated males 16 to 19, zero in unvaccinated; 18 in vaccinated males 16-39, three in unvaccinated.

CDC (later peer-reviewed) Observational study of VAERS data finds 4,496 reports of death. Four deaths from myocarditis, none with a death certificate or autopsy.

Oct. 28 US, China VAERS review finds increased risks of myocarditis and pericarditis following mRNA vaccination.

Italy One case of pericarditis identified in study of single center.

Denmark Case report of 17-year-old previously healthy male with multisystem inflammatory syndrome after second Pfizer dose.

Oct. 29 South Korea Previously healthy 38-year-old female suffered a heart attack after COVID-19 vaccination. Researchers: "Contrary to most previous reports, the present case demonstrated that the clinical course of the COVID-19 vaccination-related myocarditis is not always benign."

Greece Case series, including two patients with "cardiac tamponade requiring emergent pericardial decompression," after COVID-19 vaccination.

Oct. 30 UK Cardiac MRI imaging, including patient with acute myocarditis after mRNA vaccination.

Switzerland Seventeen patients report to single center between March and July 2021 with myocarditis after COVID-19 mRNA vaccination. Thirteen patients had recovered or were recovering at time of discharge.

November 2021:

US Case report of previously healthy 19-year-old with severe chest pain three days after receiving a second dose of a mRNA shot. Followup cardiac MRI showed small abnormality.

Italy Previously healthy 20-year-old male hospitalized two days after second dose of Pfizer's vaccine.

Italian Society of Cardiology says temporal link between myocarditis and COVID-19 vaccination "is not a proof of causality and only dedicated studies will be able to clarify this aspect."

Nov. 1 England Risk-benefit analysis from England that copies CDC method. Vaccinating 12- to 17-year-olds predicted to prevent up to 4,430 hospital admissions and 36 deaths over 16 weeks, versus causing 160 cases of myocarditis/pericarditis.

US Case report of adolescent presenting to emergency room with chest pain and tachycardia following Pfizer vaccination.

US Retrospective study examining patients under 21 diagnosed with COVID-19 vaccine-associated myocarditis identifies 63 patients with mean age of 15.6 years. Followup of 54 patients showed resolution of symptoms in all but seven. Of 60 patients with echocardiograms done at followup, 20 percent had abnormal findings.

Nov. 2 Denmark Nationwide study from May 15 to Sept. 15, 2021, finds 15 cases among 12- to 17-year-olds. Researchers: "The incidence of myopericarditis after COVID-19 vaccination among males appears higher than reports from the United States."

Nov. 3 Germany Case report of 60-year-old man hospitalized about 24 hours after receiving second dose of Moderna's vaccine.

US Systematic review of cases through July 17, 2021, determines myocarditis primarily seen in young males within a few days of a second dose. Falsely says all patients recovered.

US Mayo Clinic case series finds seven patients with vaccine-associated myocarditis.

Nov. 5 Israel Cardiac MRIs performed on patients with postvaccination myocarditis. Researchers: "CMR imaging findings are mild and consistent with ‘classical myocarditis’. The short-term clinical course and outcomes were favourable."

Nov. 6 Japan Case report of previously healthy 25-year-old man hospitalized with myocarditis three days after receiving Moderna's vaccine.

Nov. 8 France Case report of two young males with myocarditis within days of a second mRNA shot.

Singapore Case report of 53-year-old man with myocarditis after COVID-19 vaccination.

Nov. 10 Italy Comment on using cardiac MRI for evaluation of patients with suspected myocarditis.

Nov. 11 US Eight patients aged 15 to 17 hospitalized at Nicklaus Children’s Hospital within four days of receiving Pfizer's vaccine.

Nov. 15 US Series of four patients with myocarditis-like illness following mRNA COVID-19 vaccination, including one who suffered heart failure.

Nov. 16 US Review of criteria for diagnosis.

US Case series of three previously healthy young adolescents hospitalized with confirmed myocarditis following Pfizer vaccination.

Nov. 17 Poland Case series describing imaging of myocarditis patients following COVID-19 vaccination.

Nov. 18 US Editorial calls on health care professionals to pressure parents into getting their children vaccinated. Says postvaccination myocarditis "has been relatively mild and self-limited."

Germany A 16-year-old with myocarditis after mRNA vaccination.

Canada Review of myocarditis findings on cardiac imaging.

Canada Review concludes myocarditis "may be associated" with COVID-19 vaccination.

Nov. 19 Singapore Review of cardiac manifestations after COVID-19 vaccination.

South Korea Case report of 24-year-old patient who developed pericarditis following COVID-19 vaccination.

Nov. 23 Germany, US Trends in cardiology consultations for suspected myocarditis after COVID-19 vaccination. Researchers: "CMR remains important to rule out vaccine-associated myocardial injury."

Nov. 24 Portugal Report of 39-year-old male with perimyocarditis after COVID-19 vaccination.

US Review discusses postvaccination myocarditis cases and calls for prospective studies "to better assess the risk–benefit ratios in different groups."

Nov. 26 France Data show higher number of myocarditis cases after second doses versus first doses.

Pakistan, Brazil, Afghanistan All patients presenting with chest pain and other related symptoms after COVID-19 vaccination should be considered to possibly have myocarditis, researchers say.

Nov. 27 Japan Case series of 27-year-old man and 37-year-old man hospitalized with suspected vaccine-related myocarditis after COVID-19 vaccination.

Nov. 28 US Study on cases at Beth Israel Deaconess Medical Center finds higher incidence in vaccinated patients versus control group.

China Cohort study in Hong Kong finds 18.5 cases of myocarditis per 100,000 doses in 12- to 17-year-olds,

Nov. 29 Singapore Vaccination of Singapore military personnel up to July 24, 2021, resulted in 64,661 receiving one or more doses. Three (18- to 21-year-old males) were diagnosed with myocarditis or pericarditis.

Nov. 30 Australia Report of myocarditis after COVID-19 vaccination.

US A 38-year-old man with myocarditis after first dose of Moderna's vaccine.

December 2021:

Dec. 1 Poland Series of three previously healthy males aged 17 hospitalized with sudden chest pain within 10 days of receiving a Pfizer dose. All tested negative for COVID-19 and other viruses. Researchers: "Based on the clinical presentation, a diagnosis of myocarditis associated with COVID-19 vaccination was made."

South Korea A 22-year-old woman who experienced myocarditis and other problems after receiving AstraZeneca's vaccine tested negative for COVID-19. Eventually diagnosed with MIS-A. Discharged after 74 days despite residual muscle weakness. Researchers: "Vaccine-associated MIS-C may become more common as more children receive SARS-CoV-2 vaccination."

US Analysis of records from the metro Detroit health care system finds six cases of myocarditis, one with two or more vaccine doses and five with one or zero vaccine doses.

Dec. 2 Japan Case report of previously healthy 23-year-old man hospitalized with myocarditis after second dose of Pfizer's vaccine.

Dec. 3 France Retrospective study of reported cases says occurrence "very rare" and doesn't compromise risk-benefit balance.

Dec. 4 Japan A 29-year-old previously healthy man hospitalized with acute myocarditis four days after first Moderna vaccine.

Japan Report of 19-year-old woman who experienced chest pain after second dose of COVID-19 vaccination.

Dec. 6 US Retrospective study of 26 pediatric medical centers identified 145 patients under 21 with suspected myocarditis within 30 days of COVID-19 vaccination. Twenty-six patients admitted to intensive care. Researchers: "Although this case series cannot determine causality of suspected myocarditis from COVID-19 vaccination, the number of cases of suspected myocarditis within a short time frame after COVID-19 vaccination would be unlikely to be secondary to chance alone."

France Hypothesis of mechanisms of postvaccination myocarditis.

Dec. 9 Bahrain Report of previously healthy 24-year-old male hospitalized five days after receiving Pfizer's vaccine. All viral serologies were found to be negative.

Japan Case report of 20-year-old man who previously suffered myopericarditis from influenza suffering another event after Moderna vaccination.

Dec. 10 US Search for cardiovascular events following vaccination identifies 2,785 cases of myocarditis or pericarditis reported to VAERS, claims that "the mRNA vaccine platform likely does not increase the probability of myocarditis or pericarditis."

Dec. 14 UK Self-controlled case series of people 16 and up vaccinated through Aug. 24, 2021, identifies 746 cases of postvaccination myocarditis or pericarditis, compared to 161 after a positive COVID-19 test, and 61 deaths from myocarditis after vaccination, versus zero after a positive test.

Dec. 15 Italy Search for studies that analyzed postvaccine deaths found 38 cases, including 14 after mRNA vaccine. Four had evidence of myocarditis.

Dec. 16 Denmark Sixty-nine myocarditis or pericarditis cases following COVID-19 vaccination, with some patients experiencing death or heart failure. Excluded people who tested positive for COVID-19 or had myocarditis previously.

Dec. 17 Iran Literature search finds myocarditis/myopericarditis and pericarditis were the most common adverse events among the 243 reported cardiac complications after mRNA COVID-19 vaccination. Recommends large-scale observational studies.

Dec. 21 South Korea Review of safety monitoring finds one post-vaccination myocarditis death.

South Korea, Europe Another literature search finds most patients male, claims all patients had favorable course but excludes death reports.

US Survey sent to pediatric cardiologists and infectious disease specialists at 107 institutions finds "marked variability in diagnosis and management of" postvaccination myocarditis.

Dec. 24 South Korea Nationwide retrospective study of high school seniors who received the Pfizer vaccine identified a rate of myocarditis and/or pericarditis as 1.8 per 100,000 in first-dose recipients and 4.3 per 100,000 in second-dose recipients.

Dec. 25 Japan Case report of 53-year-old man hospitalized after receiving Pfizer's vaccine.

Dec. 27 US, Oregon (later peer-reviewed) Cohort study of patients who received at least one dose of an mRNA vaccine between December 2020 and Oct. 2021 estimates risk among males aged 12 to 39 as 195.4 cases of myopericarditis per million second doses administered. Researchers: "We identified additional valid cases of myopericarditis following an mRNA vaccination that would be missed by the [Vaccine Safety Datalink's] search algorithm."

Dec. 29 Qatar, US Literature review of postvaccination cardiovascular events.

Dec. 30 US 67 patients with myocarditis admitted to Intermountain Healthcare between Dec. 15, 2020, and June 15, 2021, of whom 21 had a recent COVID-19 vaccination. One died.

Morocco Case report of 14-year-old with shock after Pfizer's vaccine. Discharged after seven days. Researchers: "Given the seriousness of this disease, which can be fatal in its fulminant form, further research on the causal links between myocarditis and mRNA type COVID-19 vaccination is needed, especially in view of the large number of cases reported."

January 2022:

Jan. 3 New Zealand, etc. Case report of a 57-year-old woman who, following first dose of Pfizer's vaccine, died from myocarditis. Non-vaccine causes ruled out.

Japan Report of a previously healthy 20-year-old man hospitalized with chest pain after second Moderna dose.

Jan. 5 Japan Previously healthy 26-year-old man hospitalized with chest pain after COVID-19 vaccination. Later discharged, but went on leave due to depression. Researchers: "The patient was a medical professional and was well aware that myocarditis can be fatal in severe cases, which may have been traumatic and led to depressive state. It is a priority to provide psychological support for the post-traumatic stress disorder-like depression which can occur as an adverse complication of the vaccine."

Jan. 6 Turkey Evaluation of postvaccination myocarditis patients.

Jan. 7 US Case report of previously healthy male 24-year-old with myocarditis after receiving Pfizer's second dose.

US Report of 40-year-old man with chest pain and dyspnea three days after first dose of Pfizer's vaccine.

Jan. 9 Germany Young male firefighters hospitalized with myocarditis after two doses of Moderna's vaccine. Both discharged with exercise restrictions.

Jan. 10 US Case report of a previously healthy 80-year-old woman hospitalized with severe myocarditis after receiving Pfizer's vaccination.

Jan. 11 India Series of three postvaccination myocarditis cases.

Jan. 12 US, Pakistan Report of a 59-year-old male found unresponsive hours after receiving his third dose of an mRNA shot. COVID-19 test was negative and other viral infection panel was "nonsignificant." Patient was revived and was still hospitalized when case report was submitted. Researchers: "We believe the cardiac arrest was most likely secondary to the COVID-19 booster vaccination."

Italy A 59-year-old man with myocarditis after Pfizer vaccination.

Taiwan A 94-year-old man with myocarditis after AstraZeneca vaccination.

Jan. 13 Qatar Report of acute pericarditis after booster shot.

Jan. 17 Spain Case report of 24-year-old man hospitalized with myocarditis after receiving second Pfizer dose.

Canada Report of previously healthy 49-year-old man with pericarditis after second Moderna dose.

Jan. 18 US Case series of young men hospitalized after mRNA vaccination.

UK Estimate of benefits of extending space between primary series doses.

Japan Case report with heart failure.

Jan. 19 Singapore Of 34 deaths within 72 hours of receiving a COVID-19 vaccine between Feb. 1, 2021, and June 30, 2021, none had signs of myocarditis.

Jan. 21 Spain Meta-analysis of myocarditis after COVID-19 vaccination.

Jan. 22 Italy Series of six patients who experienced cardiac involvement after second mRNA dose between August and September 2021.

Jan. 24 China A 57-year-old woman and a 63-year-old man hospitalized after receiving mRNA vaccines.

Australia Case report of 20-year-old man who developed symptoms 12 hours after receiving second Pfizer dose.

Jan. 25 CDC Analysis of VAERS myocarditis reports identifies 1,991 lodged for people aged 12 or older, with 1,626 meeting CDC case definition. Rates highest after second dose in males aged 16 or 17, 105.9 per million Pfizer doses. Underreporting deemed likely, as has historically been the case for VAERS.

Hong Kong Case-control study across Hong Kong finds increased risk of carditis with Pfizer vaccination.

Jan. 27 Turkey A 14-year-old previously healthy male developed myopericarditis after receiving second dose of an mRNA vaccine.

Greece Case report of 56-year-old doctor who developed symptoms "mimicking a heart attack" a few days after receiving Pfizer's second dose.

Jan. 28 Canada Case series of 10 individuals with COVID-19 vaccine-related myocarditis, confirmed by cardiac MRI.

Jan. 30 US Review of 40 case reports.

Jan. 31 Iran Review finds chest pain most common symptom.

February 2022

Feb. 1 Iran Case report of 29-year-old man hospitalized with myocarditis after receiving Russia's Sputnik V vaccine.

Israel Series of four patients with myocarditis after receiving third dose of Pfizer's vaccine.

Norway, etc. Review of clinical presentation and management.

Feb. 2 Turkey Report of 17-year-old with myocarditis after Pfizer vaccination.

Feb. 7 UK, Greece, Israel Pooled analysis from literature search includes two deaths, seven intensive care unit admissions.

Japan Case report of 50-year-old man admitted 10 days after receiving second dose of Pfizer's vaccine. Experienced shock and heart failure.

Feb. 9 Japan Previously healthy 26-year-old man passed out while eating after receiving first dose of Pfizer's vaccine.

FDA Editorial says "the societal benefit of mass vaccination is overwhelming."

Feb. 11 Japan Previously healthy 20-year-old man admitted after second dose of Moderna's vaccine.

US Report of 18-year-old male hospitalized with myocarditis after COVID-19 vaccination.

Feb. 12 US A 69-year-old female with pericarditis after receiving a Moderna booster.

Feb. 13 Japan Case report of a 48-year-old woman who suffered shock and fulminant myocarditis after second dose of Moderna's vaccine.

Feb. 14 US Analysis of autopsies of two young boys finds unusual presentation. Death certificate of one listed myocarditis.

Germany Case series of four patients with acute myocarditis/pericarditis within 17 days of mRNA vaccination. Researchers: "In view of its rarity and mild course, the risk–benefit ratio of vaccination remains positive compared to potential SARS-CoV-2 infection."

Feb. 15 Canada Twenty-one patients with postvaccination myocarditis and at least one abnormality on cardiac MRI. All were asymptomatic in short-term followup.

Feb. 16 US, Illinois Case report of 44-year-old male hospitalized after receiving second dose of Moderna's vaccine.

Feb. 17 Oman Report of previously healthy 37-year-old man hospitalized with myocarditis for 16 days after receiving Pfizer's vaccine.

US Previously healthy 19-year-old hospitalized with myocarditis after receiving a COVID-19 vaccine.

Feb. 18 US Case report of 24-year-old man hospitalized with myocarditis shortly after receiving first Moderna dose. Followup at about three months showed no abnormalities.

Japan Report of 77-year-old man who suffered shock. Discharged 64 days after vaccination.

Feb. 21 Spain A 24-year-old man hospitalized after third dose of Pfizer's vaccine. Other potential causes ruled out.

Feb. 22 Italy Three deaths determined to be probably or definitely caused by myocarditis after vaccination.

Feb. 23 Singapore Analysis of reported myocarditis and pericarditis cases identified, as of the end of July 2021, a total of 34 cases out of 7.1 million doses administered.

Austria, Germany Series of young males who received heart failure therapy after Pfizer vaccination.

Feb. 25 Singapore Literature review finds two to five myocarditis cases per million vaccine doses.

Hong Kong 22.1 cases per 100,000 doses among adolescents who received at least dose dose of Pfizer's vaccine between March 10 and Oct. 18, 2021.

March 2022

March 1 Italy, etc. Imaging of 27 patients due to suspected heart inflammation following COVID-19 vaccination reveals late gadolinium enhancement (LGE), matched with criteria of myocarditis.

March 2 South Korea Retrospective study of two emergency departments finds myocarditis diagnosed in four males (17 to 49) between June 1, 2021, and Oct. 15, 2021.

March 4 Israel Case series of four patients diagnosed with myocarditis within 21 days of Pfizer's third shot, between July 13 and November 2021. March 5 Japan Report of a 45-year-old woman hospitalized with acute myocarditis after second dose of Moderna's vaccine.

US A 21-year-old previously healthy male hospitalized after receiving Pfizer's vaccine. Researchers: "Since our patient had positive serology for COVID-19 infection, the vaccination in combination with previous infection may have coalesced as trigger for the post-infectious cytokine-mediated hyper-inflammatory process typically seen in MIS-A."

March 7 Italy Series of 20-year-old and 21-year-old males with no past medical history experiencing chest pain three days after second Moderna dose. Imaging confirmed acute myopericarditis.

March 8 Germany Report of 21-year-old man hospitalized two days after second Pfizer dose. Eventually recovered.

US Review article falsely states "no deaths from myocarditis post-mRNA COVID-19 vaccination have been reported in the USA."

March 9 Netherlands, UK Review concludes benefits outweigh risks for all age groups.

March 10 Israel Study of nationwide data identifies 15 cases, after excluding two due to "reasonable alternative diagnoses," in children aged 12 to 15 after Pfizer vaccination between June 2 and Oct. 20, 2021.

Germany Imaging of patients with myocarditis after COVID-19 vaccination.

Canada, Chile Imaging report from adolescent male hospitalized after receiving Pfizer's vaccine.

March 11 Sweden Case report of 20-year-old hospitalized after Moderna second dose.

March 14 Canada Report of previously healthy 45-year-old woman hospitalized one week after first Moderna shot.

March 15 Poland Series of five teenagers who suffered myocarditis after COVID-19 vaccination. Followup after at least 106 days revealed "persistent myocardium injury features."

March 16 American College of Cardiology guidelines for diagnosing and treating postvaccination myocarditis.

Italy Three patients with myocarditis following Pfizer vaccination.

March 18 Japan Case report of 17-year-old boy with history of myocarditis hospitalized for 23 days after receiving second Pfizer dose.

Italy Report of previously healthy 30-year-old man hospitalized with myocarditis after receiving Pfizer's vaccine.

March 20 South Korea A 48-year-old female needed heart transplant after vaccination with the AstraZeneca and Pfizer vaccines. Autopsy of organ revealed giant cell myocarditis "possibly related to the vaccines."

March 21 Ireland, etc. Literature review says causality not established.

Hong Kong Analysis of health records identified 38 myocarditis cases after Pfizer vaccination.

US Says benefits outweigh risks even for young males even after estimating 601 myocarditis cases per million among males 12 to 15, drawing from TriNetX Research Network.

March 22 Greece Review considers similarities between postvaccination and hypersensitivity myocarditis.

March 23 Israel Imaging six months after post-Pfizer myocarditis finds evidence of residual scarring.

Japan Review says postvaccination myocarditis lower than post-COVID-19 myocarditis.

UK One hundred and five deaths from cardiac-related causes after COVID-19 vaccination in people aged 12 to 29 within 12 weeks of vaccination.

March 25 US Case series of 16 children admitted to Seattle Children's Hospital with chest pain and elevated troponin from April 1, 2021, to Jan. 7, 2022, within one week of receiving Pfizer's vaccine. Persistent findings on imaging up to eight months after.

Hong Kong Study from January 2020 to mid-2021 found four COVID-19 patients suffered myopericarditis, compared to 42 within 14 days of vaccination.

Japan Case report of a previously healthy 13-year-old male hospitalized after Pfizer vaccination who was unable to sleep due to intense chest pain.

US Experts come out against COVID-19 vaccination of healthy children.

March 28 Japan Description of Japanese health council's monitoring of myocarditis.

US Followup cardiac MRIs for seven patients who were hospitalized with myocarditis finds some LGE not resolved, indicating heart scarring.

March 29 Korea Case report of a 63-year-old woman who died after receiving second dose of AstraZeneca's vaccine.

March 30 US Report of 84-year-old male hospitalized after receiving Pfizer's vaccine.

Chile Child with myocarditis after COVID-19 vaccination.

March 31 Spain Case report of 62-year-old woman hospitalized after third dose of Moderna's vaccine. Eventually discharged.

April 2022

Pakistan, China Literature review finds majority of patients recover at least partially, with chest pain and fever most common symptoms.

April 1 CDC Data on cardiac complications following vaccination or infection analyzed from 40 health care systems.

April 4 Singapore Case report of woman with myocarditis after Pfizer vaccination.

Japan Report of 59-year-old man with pericarditis after COVID-19 vaccination.

April 5 Egypt, etc. Literature review says combination of intravenous immunoglobulins and corticosteroids may be effective treatment, especially in severe cases.

Grenada Case report of myopericarditis in 25-year-old man after COVID-19 vaccination.

April 6 US A 16-year-old male hospitalized with chest pain 48 hours after receiving second dose of Pfizer's vaccine. Researchers: "This case demonstrates the rapid recovery with no sequelae following this adverse effect, highlighting that the benefits of the COVID-19 vaccination most likely outweigh the risks."

Australia Clinical review guide.

April 7 Portugal Case report of 32-year-old male hospitalized after second dose of mRNA vaccine.

April 8 Germany Series of four people aged 18 to 42 hospitalized with myocarditis after COVID-19 vaccination.

Israel Report of severe myocarditis after Pfizer booster.

April 11 US Patients hospitalized with symptomatic myocarditis after COVID-19 vaccination.

Singapore Meta-analysis of reported postvaccination myocarditis cases.

Turkey A 57-year-old female with myocarditis after Pfizer's vaccine.

April 14 US Out of 47,999 people from Mayo Clinic Enterprise who received three doses of an mRNA vaccine, five had myocarditis or pericarditis.

New Zealand Case series of 12- and 14-year-old brothers both hospitalized with myocarditis after second doses of Pfizer's vaccine. Normalization at followup.

April 15 US Case report of 48-year-old male presenting with chest pain after second dose of Moderna's vaccine.

Iran Report of previously healthy 32-year-old female presenting with myocarditis following first dose of AstraZeneca's vaccine.

Israel Study finds no elevated incidence of pericarditis or myocarditis in adult COVID-19 patients.

April 18 US Literature review says postvaccination myocarditis "is mild and self-limiting" based on studies, but "long-term evidence is lacking."

Qatar Case report of previously healthy 22-year-old male hospitalized after receiving second dose of Moderna's vaccine.

April 19 US Biopsy-confirmed case of 63-year-old man hospitalized several weeks after Pfizer vaccination. Researchers: "Given the limited data, there are no COVID-19 vaccination guidelines in patients with myocarditis, although the authors suggest avoidance in life-threatening cases."

April 20 UAE Report of 27-year-old male after second Pfizer dose.

Nordic Study examining data from Denmark, Finland, Norway, and Sweden finds heart inflammation requiring hospital care was more common among people who received COVID-19 vaccines than those who did not.

April 21 Taiwan Case report of previously healthy 44-year-old female hairdresser hospitalized with "stabbing chest pain" after receiving AstraZeneca's vaccine. Researchers: "Vaccine-related myocarditis was highly suspected. Currently there is no established test to confirm the causal relationship."

Iraq Case series of seven patients with myocarditis after mRNA vaccination. All symptoms resolved.

Israel One hundred ninety-five cases of postvaccination myocarditis identified among those 12 and older.

April 22 US Literature review says more studies "needed to better evaluate risk factors, and long-term outcomes of COVID-19 mRNA vaccine myocarditis."

April 25 Canada Case report of 49-year-old woman hospitalized six days after receiving a Pfizer dose, which followed an AstraZeneca dose. Experienced heart attack and acute kidney injury. Non-vaccine causes ruled out.

US Report of a 19-year-old male with asthma hospitalized with chest pain after receiving first dose of Moderna's vaccine.

South Korea A 17-year-old boy with myocarditis after first dose of Pfizer's vaccine.

Italy Analysis of VAERS reports.

US Case report severe myocarditis in 25-year-old man after vaccination.

April 26 FDA Risk-benefit modeling estimates, in worst case scenario, risks still outweigh benefits, but that the vaccines will cause 98 to 186 myocarditis cases per million doses in males aged 16 or 17.

Japan Report of 17-year-old previously healthy male whose myocarditis remained visible in cardiac MRI.

April 27 Germany A 23-year-old male hospitalized after second Moderna dose. Three month followup cardiac MRI showed some abnormalities.

Japan Case series of four patients diagnosed with myocarditis after mRNA vaccination.

April 28 US Followup MRIs on 15 patients finds LGE persistent in 80 percent of patients. Researchers: "Follow-up CMR 6–12 months after acute episode should be considered to better understand the long-term cardiac risks."

US Emergency cardiovascular events in Israelis under 40 increased during COVID-19 vaccine rollout.

May 2022

May 1 South Korea Report of 22-year-old man with postvaccination myocarditis.

May 3 Germany Prospective study imaged 41 volunteers aged 18 to 50 before and after a third shot. Subclinical pericarditis observed in one.

US A 57-year-old man with history of COVID-19 suffers myocarditis after vaccination.

Canada Followup imaging of 13 patients showed persistent LGE, "likely reflecting myocardial fibrosis."

May 5 Malaysia Case report of 24-year-old man who experienced days of chest pain about nine weeks after receiving second dose of Pfizer vaccine. Diagnosed with myocarditis.

May 6: Canada Review says symptoms resolve in most patients within three weeks.

May 7 Pennsylvania Case report of 18-year-old male with myocarditis after Moderna's vaccination, with prior infection.

May 8 US Report of 64-year-old male with postvaccination hemorrhagic pleuropericarditis.

May 9 South Korea Risk of severe adverse events such as myocarditis after COVID-19 vaccination was 6.85 per 100,000 vaccinated individuals, VAERS analysis finds.

May 10 South Korea Case series of 40 adolescents with myocarditis after COVID-19 vaccination.

May 11 US At followup ranging from 1 to 4 months, nine myocarditis patients were asymptomatic but two reported chest discomfort and cardiac MRI results had not fully improved.

May 13 Japan Case report of 41-year-old with acute myocarditis after Pfizer vaccination.

May 15 Japan Series describes biopsy results of four patients with clinically suspected myocarditis after COVID-19 vaccination.

Japan Case report of pericarditis after COVID-19 vaccination.

May 17 Thailand A 55-year-old woman hospitalized after receiving AstraZeneca's vaccine.

Japan A 88-year-old female with postvaccination pericarditis.

May 18 Italy Case report of 27-year-old man who suffered recurrent myocarditis after Pfizer vaccination. Researchers: "In this case, the risk-benefit ratio is very balanced, and it is really difficult to determine which side it hangs the most."

South Korea Report of 38-year-old woman with biopsy-confirmed myocarditis after COVID-19 vaccination.

Japan Three young patients with severe chest pain after COVID-19 vaccination.

May 19 Egypt Systemic review of cases concludes myocarditis temporally associated with mRNA vaccines.

May 21 US Case report of 74-year-old male hospitalized after second dose of Pfizer's vaccine. Later hospitalized again.

May 23 Michigan Report of 30-year-old man with prior COVID-19 infection.

May 24 Greece Review of myocarditis epidemiology.

May 25 UK Review of reported cases from UK, US, and Europe.

Iran Review analyzes cardiac MRI findings across myocarditis patients.

May 26 Japan Case report of 69-year-old man who experienced heart failure after receiving first dose of Pfizer's vaccine.

May 27 Iraq, UAE Review of reports says "only three patients died."

May 28 Australia Review of cases, risk factors, and treatment strategies.

Germany Report of 29-year-old hospitalized with myocarditis after receiving AstraZeneca's vaccine three days prior.

June 2022

June 1 Canada Rate of postvaccination myocarditis higher among Moderna recipients when compared to Pfizer recipients.

US, South Korea Review of case reports finds 1.1 percent reported mortality.

June 2 Germany, etc. Eight patients between 13 and 56 vaccinated with an mRNA dose between January and August 2021 who developed cardiac side effects.

June 3 New Jersey Report of 45-year-old male hospitalized after Moderna vaccination.

Canada, Iran Review of studies claims postvaccination myocarditis cases "resolved entirely."

June 6 US Review of clinical presentations and treatment.

June 11 US Comparison of cardiac MRI results from patients with postvaccination myocarditis and patients with myocarditis from other causes finds signs the latter are more serious.

June 10 South Korea Analysis of adverse event reports finds 74 suspected cases of myocarditis/pericarditis in 12- to 17-year-olds from March 5, 2021, to Feb. 13, 2022.

June 11 US (FDA) Four hundred eleven myocarditis cases in health claims database within seven days of COVID-19 vaccination. Increased risk among men aged 18 to 25. Researchers: "Our study results, along with the benefit–risk profile, continue to support vaccination using either of the two mRNA vaccines."

June 12 Greece Two men hospitalized after mRNA vaccination.

Spain Two cases of pericarditis reported by same group that reported the first case report of myocarditis in the world.

June 13 US (Veterans Affairs) One hundred twenty-eight cases of myocarditis or pericarditis after mRNA vaccination in cohort of 433,672 U.S. veterans.

June 14 Australia Three patients with myocarditis or pericarditis after mRNA vaccination.

June 15 India Case report of young man with myocarditis after Covaxin vaccination.

Japan Report of 76-year-old woman with myocarditis following third Pfizer dose.

June 16 US Review of studies among athletes says myocarditis after COVID-19 infection higher than after COVID-19 vaccination, citing data from before June 2021.

June 21 Hong Kong Twenty-one heart failure events after Pfizer vaccination and 54 after CoronaVac vaccination, and 21 sudden deaths, among people with at least one dose from Feb. 23, 2021, to Sept. 9, 2021.

Japan Case report of postvaccination myocarditis. MRI performed six months later showed lingering abnormalities.

June 22 Germany Case series of 14 people who suffered biopsy-confirmed myocarditis after COVID-19 vaccination. Two had to be resuscitated before admission to the intensive care unit. Researchers: "The present case series reveal that cMRI was able to detect myocardial inflammation in only 33.3% (2/6) of the cases. Thus, EMB remains the definite standard in the diagnosis of viral and inflammatory cardiomyopathy."

June 24 US, China Analysis of VAERS data finds myocarditis reports rare.

US (CDC) Editorial says available evidence "supports an association between mRNA COVID-19 vaccination and myocarditis or pericarditis."

June 23 US Literature review of COVID-19 and vaccination effects in athletes.

June 22 Malaysia No increased risk for myocarditis after COVID-19 vaccination, analysis of national data finds.

June 25 France Nationwide review identifies 876 postvaccination pericarditis and myocarditis cases from May 12, 2021, to Oct. 31, 2021, with higher rates after Moderna vaccination. One case per 5,900 Moderna second doses among males aged 18 to 24.

June 26 Thailand Review suggests deferring second doses in people with myocarditis or pericarditis after first dose "until further safety data become available."

Thailand Case report of 31-year-old hospitalized with myocarditis after AstraZeneca vaccination.

June 27 Italy Review examines impact of vaccination schedule.

June 28 Australia Seventy-five confirmed myocarditis cases in 12- to 17-year-olds as of Feb. 22, 2022.

June 29 US Severe case reported in previously healthy man after third dose of a COVID-19 vaccine.

June 30 US Case report review concludes severity of myocarditis worse among adults.

July 2022

July 1 Greece VAERS review finds peak myocarditis occurrence one to three days after COVID-19 vaccination; peak for pericarditis 15 to 30 days after vaccination.

July 2 Middle East, China Review of large-scale surveillance studies of Pfizer's vaccine finds myocarditis is "consistently associated" with the shot.

July 3 Japan A 27-year-old man became unconscious during sports practice eight days after Moderna vaccination, and died 28 days later. A biopsy performed before death showed no evidence of myocarditis but an autopsy revealed "obvious severe myocardial inflammation findings, leading to the diagnosis of myocarditis."

July 4 Japan Prospective study of health care workers receiving a COVID-19 vaccine booster identifies two cases of myocarditis among 3,821 subjects.

US Case report of 23-year-old man who experienced myocarditis in 2017 and experienced it again after second dose of Pfizer vaccination. Researchers: "We suspect the etiology of his recurrent myocarditis was incited by his Pfizer-BioNTech SARS-CoV-2 vaccination"

July 5 Turkey, etc. Literature review notes myocarditis "is considered as a common cause of sudden cardiac death."

July 7 US A 45-year-old man with chest discomfort after COVID-19 experiences recurrence of symptoms after first COVID-19 vaccine dose. Admitted to the hospital after second dose with MRI-confirmed myocarditis.

July 8 Canada Two children with MIS-V within six weeks of Pfizer vaccination. Tested negative for COVID-19.

Japan Review examines possible mechanisms of COVID-19-vaccination-related myocarditis and other hypersensitivity reactions.

Italy Literature review concludes benefits of vaccination "appear" to outweigh risk of myocarditis.

Japan A 32-year-old with fulminant myocarditis five days after first dose of Moderna's vaccine. Researchers: "The mechanism of COVID-19 vaccine-associated myocarditis needs to be urgently investigated."

July 9 Japan Patient with myocarditis following third dose of Moderna's vaccine.

July 11 Germany Case report of 32-year-old man hospitalized after receiving Pfizer vaccination who went on to receive additional doses "which were tolerated under ongoing immunosuppressive therapy without any notable adverse events or heart failure aggravation."

Taiwan Review concludes benefits of vaccination outweigh risks for children.

US Case report of young male hospitalized with myocarditis after Covaxin vaccination.

July 13 Canada Review calls for prospective studies.

US Analysis of Cleveland Clinic records show one in 34 patients with history of myocarditis experienced a recurrent case after two doses of mRNA.

Australia Record review identifies 33 patients aged 12 to 18 who presented with myocarditis to Monash Children's Hospital between Aug. 1 to Dec. 31, 2021.

Denmark Cohort study finds nearly 100 myocarditis or pericarditis cases.

July 14 India Review of myocarditis cases in previously healthy individuals.

Germany Analysis of patients imaged with myocarditis symptoms after infection or vaccination.

US (CDC) Forty-five myocarditis events reported in children 5 to 11, some verified, during first four months of Pfizer vaccine administration to the age group.

July 15 Bangladesh Case report of 15-year-old female hospitalized one day after receiving second dose of Pfizer's vaccine. Became unconscious but eventually improved.

July 16 US Review calls for standard criteria for using cardiac MRIs to diagnose myocarditis in children.

July 18 Italy Patients with resolved myocarditis received COVID-19 vaccine doses with no apparent recurrence, though no imaging was performed.

July 19 South Korea Report of a 16-year-old girl treated for three months for postvaccination myocarditis.

Turkey Two intern doctors experience vaccine-induced myocarditis in the same shift.

July 20 Germany Review calls for autopsies of deaths following vaccination.

India Cohort study from one hospital from July 2021 to December 2021 identifies one postvaccination case.

Qatar Review of six studies from 2021 finds some children experienced chest pain with postvaccination myocarditis.

Hong Kong Review finds symptoms quickly resolve in most cases.

US Kaiser Permanente study of adults who received up to three doses between Dec. 14, 2020, and Feb. 28, 2022, and were diagnosed with myocarditis within 21 days identifies 41 cases. One death (attributed to cancer).

July 25 US Review comparing benefits and risks.

New Zealand Case report of 18-year-old who was awoken 15 hours after second Pfizer dose and admitted to hospital with pericarditis. Patient did not appear for three-month followup cardiac MRI.

US No persistent symptoms at a median of 159 days in six myocarditis patients with median age of 16.

July 26 Denmark Among children 5 to 11, between Nov. 25, 2021, and March 1, 2022, one case of myopericarditis was identified.

July 27 US Case report of 8-year-old with myocarditis after second COVID-19 vaccine dose.

July 28 Italy Four hundred forty-one people developed postvaccination myocarditis between Dec. 27, 2020, and Sept. 30, 2021.

South Korea, US Case report of 59-year-old man hospitalized after first dose of Pfizer vaccine.

UK Review of cases finds 94 percent were among males.

Spain Report of 72-year-old female with myocarditis after third Pfizer dose.

July 29 Israel Case series of all rheumatology centers in Israel finds nine 16- to 21 year-olds who developed myocarditis after second Pfizer dose.

July 30 Canada Myocarditis/pericarditis risk higher after Moderna's shot compared to Pfizer's shot.

August 2022

Malaysia

College of Paediatrics, Academy of Medicine of Malaysia statement (pdf).

Italy Case report of deferred postvaccination myocarditis.

Aug. 1 Japan A 60-year-old woman hospitalized after second dose of Pfizer's vaccine. Discharged after three weeks.

Italy, Sweden Followup with transthoracic echocardiography with 28 patients identified some lingering problems. Researchers: "This case series shows a higher incidence of acute pericarditis in patients administered with COVID-19 vaccines than previously estimated, probably because of a more comprehensive assessment of clinical as well as echocardiographic parameters."

Aug. 2 Germany Case report of 35-year-old man who suffered myocarditis after Pfizer vaccination and clozapine initiation.

Aug. 3 UK, etc. Review of clinical characteristics of myocarditis patients.

Aug. 4 Italy Incidence of MIS-C after COVID-19 infection higher than myocarditis after vaccination in Italian region from March 2020 to July 2022.

Japan Report of 18-year-old with postvaccination pericarditis.

Denmark Imaging of 10 young patients finds "normal to mildly impaired cardiac function."

Aug. 5 US (CDC) Myocarditis and pericarditis cases recorded shortly after Novavax vaccination, "suggesting a possible causal relationship."

Iran Report of 72-year-old male who developed symptoms of heart failure after receiving COVID-19 vaccine. Surgery to remove pericardium done.

Aug. 6 Canada Imaging study finds persistence of abnormal LGE beyond three months. Researchers: "Regional fibrosis following edema resolution was commonly observed, justifying need for ongoing surveillance."

Aug. 8 Thailand (later peer-reviewed) Prospective study of 301 students at two schools in Thailand finds 29 percent of the youth, aged 13 to 18, experienced cardiovascular effects after Pfizer vaccination. Myopericarditis confirmed in one patient; six had suspected pericarditis or myocarditis.

US (Moderna) Three thousand, one hundred and seven reports of myocarditis after vaccination received from Dec. 18, 2020, to Feb. 15, 2022, in Moderna's global safety database. Higher than expected rates in males aged 18 to 24.

Japan Case report of 14-year-old boy who suffered acute myocarditis after COVID-19 vaccination.

Aug. 9 Greece A 50-year-old man with acute myopericarditis after second Pfizer vaccination. Tested negative for COVID-19. Discharged after six days. Post-six-month imaging showed signs "compatible with healed myocarditis."

Aug. 10 US Case report of 16-year-old male hospitalized with chest pain.

Aug. 11 Brazil Theories on myocarditis and its outcomes, including sudden deaths.

Australia Risk-benefit model estimates benefits of COVID-19 vaccination outweigh risk of myocarditis.

Aug. 15 US Case report of a 63-year-old woman with myocarditis after mRNA vaccination.

China Review of cases among youth.

Aug. 17 Germany Of 44 patients with symptoms suggestive of perimyocarditis after COVID-19 vaccination, imaging confirmed diagnosis in 42.

Aug. 18 Japan Case series of five patients who presented with myocarditis within 3 days of a second Pfizer dose between June 2021 and January 2022.

Aug. 19 US (CDC) Moderna and Pfizer vaccines associated with increased risk of myocarditis and pericarditis in 18 to 39-year-olds.

US (CDC) No reports of myocarditis among children 5 to 11 between May 17 and July 31, 2022. Japan Autopsy analysis of 54 deaths potentially caused by vaccine-related adverse effects finds 3 causally related to myocarditis.

Aug. 22 UK Case series of people aged 13 or older and vaccinated between Dec. 1, 2020, and Dec. 15, 2021, finds higher risk of myocarditis after Moderna second dose among men than from COVID. Identifies 100 deaths within 28 days of hospital admission from myocarditis.

Aug. 23 Germany Imaging from 10 vaccinated patients with myocarditis compared to 10 patients suffering from viral myocarditis. Researchers: "The observed imaging markers were closely related to regular viral myocarditis in our cohort."

Aug. 24 Australia Report of a near-fatal case.

Aug. 25 Japan Report of a healthy 14-year-old male who experienced worsening chest pain after receiving Pfizer third dose. Symptoms eventually resolved.

South Korea Report of 30-year-old man with myopericarditis following Novavax vaccination.

Aug. 26 Brazil Report of 49-year-old female with pericarditis after Pfizer vaccination.

Japan Report of postvaccination myocarditis in 13-year-old twins.

April 27 US (CDC) Comparison finds outcomes of traditional myocarditis worse than myocarditis after COVID-19 vaccination.

Aug. 29 US, India Review compares myocarditis after COVID-19 vaccination and infection.

Aug. 30 Japan Autopsy report of a 61-year-old woman who died with severe myocarditis 10 days after receiving COVID-19 vaccine. Tested negative for COVID-19.

Aug. 31 Italy After excluding people with previous COVID-19, analysis covers 24 patients admitted to single center for pericardial diseases following COVID-19 vaccination from April 1, 2021, to April 15, 2022.

September 2022

Sept. 1 Italy Thirteen patients who received COVID-19 vaccines despite history of myocarditis do not experience symptoms.

Qatar, UK Case series includes one patient with postvaccination myocarditis.

Sept. 2 Japan Report of 49-year-old man who needed mechanical circulatory support.

Sept. 5 Japan Report of postvaccination myocarditis in elderly woman following COVID-19 vaccination. Treated using steroid pulse therapy.

Sept. 6 China, US Review concludes that mRNA vaccines appear to be associated with pericarditis and myocarditis.

Israel Review of reports to Israeli Ministry of Health rom July 31, 2021 (first day of booster), through Nov. 5, 2021, finds 91 reported cases of myocarditis, including 35 within 30 days of booster vaccination. Myocarditis rates among males aged 16 to 19 were 64 per million boosters.

Sept. 7 South Korea Report of 38-year-old woman hospitalized five days after first Pfizer vaccination. Developed biventricular failure, cardiogenic shock and acute renal failure. Discharged after one month. MRI at six months showed persistent LGE.

Italy Inpatient records from University of L'Aquila identifies cases of pericarditis after mRNA vaccination.

China Case report of 36-year-old woman who died after ZF2001 vaccination. Autopsy requested by family due to temporal link to vaccination. Researchers: "Although potential cause of myocarditis due to viral infection cannot be completely excluded because no viral culture/viral DNA/RNA detection were performed, myocarditis could be a severe side effect of the protein subunit of COVID-19 vaccine."

US Chronic pericarditis in 32-year-old athlete that may have been caused by COVID-19 vaccination.

Sept. 8 Japan Report of 15-year-old male hospitalized after second Pfizer dose with chest pain. Lingering LGE. Researchers: "Although post-COVID-19 vaccination myocarditis has a favorable prognosis and is considered curable, it may leave abnormalities in the myocardium, as observed in this case; it may therefore be premature to declare it as a complication with a good prognosis."

Sept. 12 China Analysis of VAERS reports finds no increase in risks of myocarditis or pericarditis following a booster.

Sept. 13 Italy Report of 30-year-old man who did not respond to conventional therapy and was successfully treated with anakinra.

Sept. 14 Israel Seven patients received an initial and follow-up scan a median of 159 days later, with abnormal results remaining in some patients.

US Another followup, from 9 young males. Over a median followup of 146 days, none of the nine male patients experienced recurrent myocarditis, heart failure, or arrhythmias, or were readmitted to the hospital for any cause. Abnormal global longitudinal strain and persistent LGE found in most.

Sept. 20 Malaysia Review outlines guidance for autopsies of deaths after COVID-19 vaccination.

Sept. 21 CDC Follow-up surveillance study of cases reported to VAERS reliant on surveys finds 54 percent of patients with follow-up MRIs had abnormal findings such as swelling or scarring.

Sept. 23 China Researchers drew from experience of adverse events after Hepatitis B vaccination to provide insights into post-COVID-vaccination myocarditis.

Hong Kong Followup 60 to 180 days after initial diagnosis finds normal results on treadmill testing but significant weight increases and persistent symptoms.

Sept. 25 China, US Systematic review and meta-analysis finds elevated rate of myocarditis in pericarditis in vaccinated people.

Sept. 26 South Korea Analysis of blood from myocarditis patient.

Italy Report of 16-year-old male whose symptoms resolved.

Sept. 28 Qatar Report of severe myocarditis in 38-year-old female.

Israel Blood samples taken during and two to four days after fourth dose showed myocardial injury in two of 324 participants.

Sept. 29 Japan Man in his 90s who experienced heart failure after receiving third dose of Pfizer's vaccine diagnosed with pericarditis after autopsy. Researchers: "Although a direct causal relationship between COVID-19 mRNA vaccination and pericarditis cannot be definitively established in the present case, no other causes were identified from the autopsy findings and laboratory results."

Singapore Analysis of institution's cohort finds five patients with heart failure, two with shock, three who were intubated, and one who died.

October 2022

US Report of 19-year-old with postvaccination myocarditis.

Oct. 1 Germany Report of a 76-year-old with history of Parkinson's disease who died three weeks after second Pfizer dose (third dose total). He received the dose despite never fully recovering from side effects from first two doses. Researchers: "While the histopathological signs of myocarditis were comparatively mild, the encephalitis had resulted in significant multifocal necrosis and may well have contributed to the fatal outcome."

Oct. 4 Saudi Arabia Case series of patients as young as 14 years old. One had persistent left ventricular dysfunction.

US (CDC) Verification of myocarditis and pericarditis cases within seven days of mRNA vaccination through VSD data finds incidence rates as high as 150.5 million after dose 2 in males 12 to 15 and 188 per million booster doses in males aged 16 or 17.

Oct. 5 Israel MRI of adolescents (age 12–15) with a clinical diagnosis of myocarditis within 42 days following a first COVID-19 vaccine dose were analyzed.

Oct. 6 Europe Statement from European Society of Cardiology says benefits still outweigh risks.

Oct. 10 Canada Report of recurrent myocarditis in 25-year-old man.

Italy Report of shock in myocarditis patient following COVID-19 booster.

Oct. 13 US Data from VAERS show three reported myocarditis cases among children in Delaware.

Oct. 14 South Korea Report of previously healthy 20-year-old man. Confirmed with endomyocardial biopsy.

Germany More myocarditis cases in Germany after COVID-19 vaccination than after COVID-19. Researchers: "We support the call for a comprehensive and careful benefit–risk evaluation of COVID-19 vaccines."

Oct. 15 US Series of five adults, aged 18 to 34, hospitalized with myocarditis after COVID-19 vaccination. Followup found two with persistent symptoms.

US Comparison of 69-year-old male with myocarditis after Moderna vaccination and 46-year-old female with myocarditis after COVID-19.

Greece Report details case and speculates that myocarditis cases cross the blood-brain barrier.

Oct. 18 Japan COVID-19 vaccination was associated with higher risk of myocarditis death across all age groups, not only young adults.

Oct. 19 US Finding of "nearly identical alterations in gene expression that would predispose to inflammation, coagulopathy, and myocardial dysfunction" among patients with heart injury after vaccination and COVID-19.

Oct. 20 Germany, Israel Antibody analysis in patients with suspected myocarditis after COVID-19 vaccination. Many underwent biopsy.

Oct. 21 Singapore Series on patients with postvaccination myocarditis and active autoimmune rheumatic diseases.

Oct. 22 Australia Report of previously healthy man who developed severe severe dilated cardiomyopathy after Pfizer vaccination.

Oct. 26 US (FDA) Surveillance of outcomes in vaccinated people aged 12 to 64 finds myocarditis meets safety signal after Pfizer vaccination.

Oct. 30 Japan Analysis of documents published by Japanese health committee identifies 476 cases of postvaccination myocarditis between Feb. 17, 2021, and Nov. 14, 2021. Researchers: "Risks of myocarditis and pericarditis following SARS-CoV-2 mRNA vaccines in Japan seems to be significantly elevated for adolescent and young adult males."

Oct. 31 Italy Series finds "persistent, although decreased, myocardial injury" in six of nine patients at 12-week followup. One still had symptoms.

November 2022

Taiwan Report of 23-year-old female with acute chest pain after first dose of Pfizer's vaccine.

Nov. 1 Saudi Arabia Case report of 18-year-old hospitalized after receiving Moderna's vaccine. Recovered after one day and discharged.

Nov. 2 Japan Report of previously healthy 13-year-old who suffered myocarditis and postural orthostatic tachycardia syndrome after COVID-19 vaccination.

Nov. 3 US (CDC) No myocarditis cases in group of 7,077 vaccinated children across Kaiser Permanente Southern California.

Nov. 4 Australia One death, 1,342 cases of myocarditis/pericarditis reported after COVID-19 vaccination in Australia.

Nov. 5 Germany Imaging study compares patients with myocarditis following COVID-19 vaccination to patients with traditional myocarditis and finds "demonstrated lower prevalence of LGE but higher prevalence of abnormal T1/T2 mapping."

Nov. 8 China Cause of death for 59-year-old man determined to be viral myocarditis combined encephalitis from COVID-19 vaccination.

Nov. 9 Germany Follow-up study finds LGE visible in all patients and two with new symptoms. Researchers: "The long-term implications of the remaining myocardial scar-tissue after vaccine associated myocarditis remain unknown warranting further studies."

Nov. 12 Italy Sixteen to 19-year-old males more likely to be harmed by Moderna's vaccine, while the risk-benefit profile was favorable for all other age groups, cohort study in Lombardy Region concludes.

Nov. 15 New Zealand Review says most cases of post-vaccination myocarditis are mild.

US Report of 19-year-old man with myocarditis after Pfizer vaccination. Researchers: "Considering the protective effects of the COVID-19 vaccine against hospitalization and death, and the low incidence of vaccine-associated myocarditis, the overall benefits of the COVID-19 vaccine would outweigh the risks. However, it is unclear if the same rate of benefit is provided by the booster doses of the COVID-19 vaccine. Thus, the decision for booster doses should be individualized based on the risks versus benefits."

Canada Rates of post-vaccination myocarditis higher after Moderna vaccination than after Pfizer vaccination, British Columbia cohort study finds.

Nov. 17 Egypt

Review posits cause of myocarditis is vaccines upregulating micro RNAs.

Nov. 18 Saudi Arabia Report of 48-year-old male hospitalized after receiving AstraZeneca's vaccine. Tested negative for COVID-19. At 39 days, all symptoms had resolved except for exertional dyspnea.

Israel Maccabi Healthcare Services analysis finds no myocarditis cases after second booster.

Nov. 21 Japan Case report of a 23-year-old male with post-vaccination myopericarditis hospitalized after receiving second Moderna dose. Researchers: "Although this episode was not fatal and there was no residual cardiac dysfunction, we advised the patient to avoid additional COVID-19 mRNA vaccines because of this episode."

Canada British Columbia researchers identify 141 myocarditis cases within 21 days of COVID-19 vaccination from Dec. 15, 2020, to March 10, 2022, with the highest observed-to-expected ratio seen after a second dose among males aged 18–29 years who received Moderna's vaccine (148.32 per 100,000).

South Korea Report of a previously healthy 17-year-old female hospitalized with chest pain three days after first Pfizer dose. After discharge, she passed out at a restaurant. Admitted to ICU. Later discharged again. Doctors found her cardiac function "did not fully recover" in followup.

Nov. 22 Singapore Myocarditis erroneously diagnosed in one case.

Nov. 23 Japan Report of previously healthy 51-year-old woman hospitalized after second dose of Moderna's vaccine. She suffered organ damage and other issues. Discharged after two weeks. Followup showed she was "clinically well." Described as possible MIS-V.

Japan Case report of 19-year-old man with heart failure.

Morocco A 23-year-old with heart problems after BIBP COVID-19 vaccination.

Nov. 24 Europe Cohort study pulling from five European databases from Jan. 1, 2020, to Dec. 31, 2021, identified background rates and increased rates of myocarditis after Pfizer vaccination in adolescents aged 12 to 17, and statistically nonsignificant increases after Moderna's vaccine.

Nov. 27 Germany: Autopsies performed at Heidelberg University Hospital on people who died unexpectedly within 20 days of a COVID-19 vaccination identified myocarditis in five people, with median age of 58. Other potential causes ruled out.

Nov. 28 Qatar Report of two cases of myocarditis in previously healthy young males after receiving Pfizer vaccination.

Nov. 29 US, etc. Review finds post-vaccination myocarditis most prevalent among young males and calls for prospective studies "to establish a concrete relationship between myocarditis and the COVID-19 vaccine."

Nov. 30 Japan Case report of 64-year-old who received a second dose after experiencing myocarditis and did not show new symptoms.

December 2022

Dec. 5 US Risk-benefit analysis for booster mandates at universities estimates that to prevent one COVID-19 hospitalization over a six-month period, 31,207–42,836 young adults aged 18–29 years must receive a third mRNA vaccine. Per hospitalization prevented, estimated 18.5-plus serious adverse events caused, including 1.5–4.6 booster-associated myopericarditis cases in males.

Hong Kong, UK One death, two heart failures from myocarditis after Pfizer vaccination, but postvaccination myocarditis compares favorably to historical myocarditis, researchers say.

Dec. 13 Taiwan Symptoms resolved in all postvaccination patients aged 12 to 18 with cardiovascular symptoms at emergency department after Pfizer vaccination. Doctors did not follow up with most.

Dec. 16 US (CDC) Clusters of myocarditis cases after second Pfizer dose in people aged 12 to 39 in tree-based evaluation from VSD.

Dec. 22 France, Italy Series of men with acute myocarditis after COVID-19 vaccination.

Dec. 23 Australia Two young patients suffer myopericarditis after Pfizer vaccination, and again after Novavax vaccination. Both had persistent symptoms.

Dec. 28 US Review finds only one in four articles on postvaccination myocarditis used four stratifiers, and men younger than 40 receiving a second dose of an mRNA vaccine are at greatest risk.

Turkey LGE present in seven of seven patients three to six months later; myocardial edema persistent in two.

January 2023

Jan. 3 Qatar High probability that some deaths after COVID-19 vaccination related to vaccination, researchers say.

Jan. 4 US Analysis of blood finds "unbound" spike protein in plasma of people with myocarditis after vaccination.

Belgium Case report of 55-year-old man who suffered myocarditis and other problems after receiving Moderna's booster.

Jan. 5 Taiwan Seventeen percent of high school students reported cardiac symptoms after second Pfizer dose in prospective study. Abnormal electrocardiogram results in one percent.

Portugal Portuguese Society of Cardiology says "unequivocal" evidence of link between COVID-19 vaccines and myocarditis

Palestine One case of myocarditis reported in survey at university.

Jan. 9 UK, Germany Imaging study of children who presented at institutions between July 2021 and August 2022 with signs of acute myocarditis after receiving Pfizer vaccines finds signs of heart scarring.

Italy Death "from COVID-19" in a person who was fully vaccinated.

Jan. 11 Japan Case report of 13-year-old with myocarditis after Pfizer vaccination.

Jan. 17 US Of 179 service members with prior vaccine-associated myocarditis who received COVID-19 vaccine, 11 developed symptoms within 30 days. All eventually recovered.

Saudi Arabia One report of myocarditis among 385 kids surveyed.

Jan. 18 Japan A 43-year-old man with myocarditis after Moderna booster.

Germany Case report of pericarditis following AstraZeneca vaccination.

Jan. 19 US A 17-year-old male with post-vaccination myocarditis still has chest discomfort six months later. Researchers: "The long-term outcomes of COVID-19 vaccine-associated myocarditis are unclear. This patient had nonsustained ventricular tachycardia over 6 months after diagnosis."

Australia Differences between Brighton and CDC definitions of myocarditis.

Greece Case report of pericarditis in woman after AstraZeneca vaccination.

Jan. 23 Japan Meta-analysis of efficacy and safety among children aged 5 to 11 pegs myocarditis incidence at 1.8 cases per million second doses.

Jan. 26 South Korea Case report of myocarditis after receipt of MVC-COV1901 vaccination.

Jan. 27 Japan Autopsy of 71-year-old man who died after first Pfizer vaccination revealed myocarditis with extensive fibrosis. Researchers: "After reviewing previous reports on mRNA COVID-19 vaccine-associated myocarditis, it seemed likely that hypersensitivity myocarditis was caused by the BNT162b2 COVID-19 vaccine."

Jan. 31 Libya, US Report of 34-year-old man with myocarditis after receiving Pfizer's vaccine.

February 2023

Feb. 1 Nordic 530 people across Nordic countries suffered myocarditis related to COVID-19 vaccination, compared to 109 with COVID-associated myocarditis. Eight cases of heart failure or death among vaccinated 12- to 39-year-olds.

Feb. 2 Italy Review notes that most studies are from the early variants, not Omicron.

Brazil Case report of 23-year-old man with heart scarring following first Pfizer dose.

Feb. 4 Japan Case report of man with postvaccination myocarditis.

Feb. 8 Iran 29-year-old female hospitalized three months after second dose of Sinopharm's vaccine. Attributed to COVID-19. Spent 11 days in hospital; evidence of long-term issues.

Taiwan 204 cases of myocarditis/pericarditis reported after vaccination from March 22, 2021, to Feb. 9, 2022.

Feb. 10 Japan Myocarditis after COVID-19 vaccination persisted for 12 months. Some patients died.

Feb. 14 India Review calls for harmonizing case definitions and issuing treatment guidelines.

US (CDC) Six cases of myocarditis, 134 cases of heart failure among fully vaccinated from January 2021 to November 2021 in a surveillance network covering 99 counties.

Spain, Venezuela Fifty-six reports of myocarditis or pericarditis reported to VigiBase following Novavax vaccination.

Feb 20 US Patient with postvaccination myocarditis experiences recurrent ventricular tachycardia. Doctors implanted a cardioverter defibrillator.

Feb. 23 Australia Retrospective analysis of patients presenting to St Vincent’s Hospital, in Sydney with suspected COVID-19 vaccine-related myocarditis and pericarditis identifies 10 cases, including one with MIS-V.

Feb. 24 US Case report of myocarditis and encephalopathy occurring at the same time following vaccination.

Israel A 22-year-old man with pericarditis after Pfizer vaccination dies.

Feb. 27 Canada Cohort analysis in Ontario finds 77 children with myocarditis or pericarditis after Pfizer vaccination out of 1.6 million doses administered.

March 2023

March 3 Germany Report of 23-year-old male without COVID-19 hospitalized after second dose of Moderna's vaccine. Discharged after eight days. Signs of damage at followup. Researchers: "Three months later the patient presented for a control examination. The patient reported to be without any complaints at rest but had not engaged in more intense physical exertion so far. Electrocardiographic findings were reduced, but still detectable."

March 6 Italy Review says COVID-19 vaccinations may be linked to increased blood pressure.

March 7 France Review of French safety system finds signal for COVID-19 vaccines and myocarditis triggered in June 2021.

March 9 Canada Prospective study finds persistent heart inflammation in two of 17 patients and LGE in 11 of 17 patients at two-month followup.

March 10 Austria, Italy Fifty-seven percent of 21 patients with suspected myocarditis after COVID-19 vaccination met updated Lake Louise criteria for myocarditis.

March 11 US Review notes that myocarditis "remains a recognized cause of sudden cardiac death in children and athletes."

Spain Advice on how to diagnose and treat postvaccination myocarditis.

March 13 US Interest in myocarditis was low until COVID-19 vaccines were rolled out, analysis of search results and reports show.

Italy Short-term followup found persistence of inflammation in almost a quarter of the cohort.

March 15 Hong Kong Case report of 72-year-old woman with myocarditis and heart failure after COVID-19 vaccination.

March 20 Japan A 14-year-old girl "died unexpectedly" two days after receiving third Pfizer dose. Researchers: "The cause of death was vaccine-related myopericarditis, which led to severe arrhythmias and progressive heart failure."

Hong Kong Heart failure, Still's disease in elderly woman after COVID-19 vaccination.

March 24 Canada Rate per million of myocarditis cases within seven days of vaccination 17.9 after second dose and 6.4 after booster dose. Highest rate 225 per million second Moderna doses in males aged 18 to 29. Highest booster rate in same population; 39 per million.

March 25 Hong Kong Increased risks of myocarditis and pericarditis after Pfizer vaccination, including after third dose.

March 27 England Researchers find no significant increase in cardiac or all-cause mortality within 12 weeks of COVID-19 vaccination compared to more than 12 weeks after any dose, but identify increased cardiac death in women after a first dose of non-mRNA vaccines.

March 28 US Three of four patients had complete resolution of symptoms at one-year followup. Remaining patient "was lost to follow up after hospitalization."

Italy VAERS analysis finds more than 5,200 reports of post-vaccination myocarditis, more than 3,500 reports of post-vaccination pericarditis.

Thailand Analysis based on reported cases find 0.97 myocarditis cases per 100,000 doses administered, with 10 deaths.

March 29: Spain Doctors report one case of acute pericarditis and one case of acute myocarditis in 15-year-old males.

April 2023

April 1 US Retrospective imaging review finds impact on myocardial strain "less significant" in post-vaccination cases compared to traditional cases.

US Case report of myopericarditis following Pfizer booster. Patient discharged after seven days.

April 3 Indonesia Two patients needed mitral valve surgery after experiencing myocarditis after COVID-19 vaccination.

Hong Kong Extended primary series interval reduced myocarditis incidence. April 4 Spain Case report of 28-year-old male with postvaccination acute myocarditis.

April 5 South Korea Records from Korea Immunization Management System from between July 19, 2021, and Sept. 30, 2022, shows 173 myocarditis cases among adolescents.

April 7 Italy Series of 26-year-old and 27-year-old men hospitalized after Pfizer booster shots. Discharged after several days and seemed recovered at four-week follow-up examinations.

April 15 Australia Twenty-nine cases of definite or probable myocarditis at children's hospital in Melbourne following vaccination, compared to five after COVID-19.

Malaysia Eighty-seven myocarditis cases identified within 21 days of vaccination between between Feb. 1, 2021, and Feb. 28, 2022.

April 17 Switzerland Patient with postvaccination myocarditis received a second dose with no problems after taking colchicine as a preventative.

April 18 Germany, Japan Review says uncertain evidence for myocarditis in the 5 to 11 age group.

April 19 Spain Series of two patients with fulminant myocarditis after mRNA vaccination.

April 21 CDC, FDA One year of safety surveillance includes 570 confirmed post-vaccination myocarditis cases. Of 36 reported deaths, most had other causes identified and the rest had "insufficient information."

April 22 US Analysis of EudraVigilance database reports finds excess risk for myocarditis.

April 24 Denmark One point six deaths from cardiovascular disease estimated for each COVID-19 death prevented by mRNA vaccination.

May 2023

May 1 US Review says that as of February 2023, literature contained descriptions of 14 deaths involving autopsy-proven myocarditis.

May 5 US Analysis of immune system reactions among myopericarditis patients.

Austria Alternative causes of death should be considered before determining vaccination was a cause, doctor says.

May 8 Australia Report of triplets with myocarditis after Pfizer vaccination.

US Case report of biopsy-confirmed eosinophilic myocarditis in 24-year-old male after COVID-19 vaccination. "

May 9 CDC One myocarditis case in pregnant women after booster.

May 10 US Some postvaccination myocarditis patients had persistent LGE in followup. No active inflammation detected.

May 11 US Review of myocarditis case rates and presentation.

Sweden Ninety-six percent of registered cases validated as actual myocarditis.

May 15 Italy Imaging results from postvaccination myocarditis cases.

May 17 Europe, etc. Review says myocarditis after COVID-19 vaccination "is rare and almost always of a benign nature."

US One hundred seventy-eight potential cases of post-vaccination myocarditis identified in Veterans Health Administration. Twenty percent of cases verified in chart review.

May 18 Japan Case report of 81-year-old man with heart failure 9 years earlier. Suffered heart failure again after COVID-19 vaccination.

Thailand Report of 13-year-old who had normalization recorded in six-month followup.

May 19 Canada Benefit-risk assessment focused on Hong Kong's single dose policy. Researchers: "The policy was highly successful in the reduction of carditis, but the trade-off is the potential cost to missed opportunities to benefit from the vaccine and to a lesser extent population-level immunity."

US Report of man with postvaccination pericarditis who received anesthesia for fluid drain. Researchers: "Further research is needed to better understand the long-term implications of pericarditis and myocarditis following COVID-19 vaccination with this vaccine and to develop strategies to minimize the risk of these complications during anesthesia."

May 22 FDA Safety signal for myocarditis and pericarditis following mRNA vaccination in children aged 5 to 17.

China Meta-analysis of 12 to 17 age group finds 43.5 myocarditis cases per million doses, up to 107.7 per million second doses in males.

May 24 Taiwan Of 681 children who presented with discomfort such as chest pain after Pfizer vaccination, 29 were diagnosed with myocarditis, pericarditis, or both. None died.

May 27 Italy, US Two children with myocarditis after vaccination experienced "persistent lesions" and were readmitted months after discharge.

May 29 Taiwan Pericarditis case after bivalent mRNA dose.

June 2023

June 1 Switzerland Case report of man in 40s with myocarditis after Moderna vaccination. Symptoms resolved "rapidly."

June 2 South Korea: Analysis of 480 cases of COVID-19 vaccination-related myocarditis, including 21 deaths, finds eight sudden deaths caused by myocarditis.

FDA Benefit-risk assessment estimates more COVID-19 hospitalizations prevented than myocarditis cases caused in all scenarios.

June 3 Turkey Case report of postvaccination myocarditis.

June 7 UK Between Feb. 22, 2021, and Feb. 6, 2022, 486 patients with postvaccination myocarditis in 16 to 39 age group. Another 823 cases among those 40 and older. Researchers: "For both mRNA vaccines, elevated risks were found in those under 40 years old, predominantly in males, were highest after the second priming dose and were generally lower in those vaccinated after a prior SARS-CoV-2 infection."

June 8 Italy One hundred and twelve myocarditis cases and 304 pericarditis cases within 28 days of COVID-19 vaccination in cohort study in the Lombardy region.

June 9 US Single-center imaging study finds improvement of left ventricular longitudinal strain over time following postvaccination myocarditis.

June 13 Korea Five hundred eleven cases of myocarditis reported after vaccination between Feb. 26, 2021, and June 4, 2022. Five were fatal.

June 14 FDA, CDC Fifty-two verified reports of myopericarditis in adults after Johnson & Johnson vaccination.

FDA, CMS Nearly 1,300 myocarditis and pericarditis cases among Medicare beneficiaries aged 65 and older after booster vaccination. No increased risk.

June 19 Spain Post-vaccination myocarditis similar to other myocarditis cases, based on imaging.

June 20 Israel No cases of myocarditis after bivalent booster.

June 27 Spain Data from 29 centers from Aug. 1, 2021, to March 10, 2022, identified 139 postvaccination myocarditis cases. 1.4 percent of the patients died as of three-month followup.

July 2023

July 1 US Cases of postvaccination myocarditis more likely to be less severe than COVID-19 myocarditis, review concludes. July 3 Indonesia Review describes postvaccination myocarditis as "relatively benign, with a median length of hospitalization of 5 days, intensive care unit admission of <12%, and mortality of <2%."

July 7 Australia Three sets of siblings, including two sets of twins, suffer chest pain after COVID-19 vaccination. Five diagnosed with myocarditis.

July 13 US Lower white blood cell counts and lower platelet concentration recorded in prospective study.

July 20 Italy Out of 460 athletes who responded to survey, none reported myocarditis after vaccination.

July 25 Denmark Increased risk of myocarditis and pericarditis after bivalent mRNA booster. 31 cases found.

July 31 Hong Kong Some patients still have problems one year later, followup finds.

August 2023

Aug. 9 New Zealand Statistically significant association between Pfizer vaccination and myocarditis/pericarditis found.

Aug. 10 Bangladesh Diagnosis of takotsubo cardiomyopathy in patient who presented with chest pain after COVID-19 vaccination.

Aug. 22 Italy Five hundred sixty-six cases of myocarditis after bivalent vaccination reported to VAERS.

Aug. 24 Canada Imaging of postvaccination myocarditis similar to myocarditis from other causes, but tends to be less severe.

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