Pfizer COVID-19 Vaccine Linked to Heart Inflammation Risk in Real-World Study

A nurse prepares a Pfizer BioNTech COVID-19 vaccination as part of a vaccine drive by the Fernandeno Tataviam Band of Mission Indians in Arleta, Los Angeles, Calif., on Aug. 23, 2021. (Lucy Nicholson/Reuters)

Real-world data from Israel linked Pfizer’s COVID-19 vaccine to an elevated risk of heart inflammation, researchers said this week.

Israeli scientists found that vaccination likely caused myocarditis, or heart inflammation, in one to five people per 100,000 who wouldn’t have otherwise suffered the condition.

However, they also said that getting COVID-19 was linked to a higher risk—with 11 inflammation events out of 100 attributed to the disease.

Most of the heart inflammation cases post-vaccination were in young males. The 21 people who had myocarditis in the vaccinated group had a median age of 25, and 90.9 percent were men.

“We estimated that the BNT162b2 vaccine resulted in an increased incidence of a few adverse events over a 42-day follow-up period. Although most of these events were mild, some of them, such as myocarditis, could be potentially serious,” they said, referring to the Pfizer-BioNTech vaccine.

“However, our results indicate that SARS-CoV-2 infection is itself a very strong risk factor for myocarditis, and it also substantially increases the risk of multiple other serious adverse events. These findings help to shed light on the short- and medium-term risks of the vaccine and place them in clinical context. Further studies will be needed to estimate the potential of long-term adverse events.”

The research analyzed adverse events reported among 884,828 vaccinated people and an equal number of people who didn’t receive a vaccine, as well as a cohort of more than 240,000 people who contracted COVID-19. It was published in the New England Journal of Medicine on Aug. 25. Dr. Ran Balicer, of the Clalit Health Services in Tel Aviv, led the research group. They were funded by Harvard Medical School and the Clalit Research Institute.

A Pfizer spokesperson told The Epoch Times in an email that the company is aware of “rare reports of myocarditis and pericarditis, predominantly in male adolescents and young adults, after mRNA COVID-19 vaccination.”

The Pfizer and Moderna vaccines utilize messenger RNA, or mRNA, technology.

The spokesperson noted that the Centers for Disease Control and Prevention describes the heart inflammation as a rare side effect.

“Patients have typically rapidly improved with conservative treatment. It is important to note that CDC continues to strongly encourage COVID-19 vaccinations for eligible individuals aged 12 and older. With hundreds of millions of doses of the Pfizer-BioNTech COVID-19 vaccine administered globally, the benefit risk profile of our vaccine remains positive,” the spokesperson added.

The Pfizer vaccine has been found in multiple countries to be associated with an increased risk of heart inflammation, including the United States. U.S. health officials added a warning to the Pfizer and Moderna vaccines in June regarding the higher risk, but have continued recommending them for use, and earlier this week, the Food and Drug Administration (FDA) gave full approval to the Pfizer vaccine.

The Pfizer vaccine, as well as shots offered by Moderna and Johnson & Johnson, had previously been made available to the public through emergency use authorization (EUA) from the FDA. The Moderna and Johnson & Johnson shots are currently still under EUA.

Dr. Grace Lee, of the Stanford University School of Medicine, highlighted how the risk of myocarditis was higher among COVID-19 patients than the vaccinated in an editorial accompanying the new study.

“What is even more compelling about these data is the substantial protective effect of vaccines with respect to adverse events such as acute kidney injury, intracranial hemorrhage, and anemia, probably because infection was prevented. Furthermore, the persons with SARS-CoV-2 infection appeared to be at substantially higher risk for arrhythmia, myocardial infarction, deep-vein thrombosis, pulmonary embolism, pericarditis, intracerebral hemorrhage, and thrombocytopenia than those who received the BNT162b2 vaccine,” Lee wrote.

Not everyone was enthused by the research, however.

Dr. Vinay Prasad said issues in the study included the lack of a one-dose cohort, as Pfizer’s regimen requires two doses, and it not identifying people who recovered from COVID-19 but didn’t get vaccinated.

“You need to report separately for boys aged 16-24, who face a vastly higher rate of myocarditis and may not gain much beyond 1 dose,” Prasad, an associate professor in the Department of Epidemiology and Biostatistics at the University of California–San Francisco, wrote on Twitter.