Approving Authority on COVID-19 Vaccines Says Underreporting of Adverse Events a ‘Common Problem’

Approving Authority on COVID-19 Vaccines Says Underreporting of Adverse Events a ‘Common Problem’
Health Canada headquarters in Ottawa in a file photo. (Sean Kilpatrick/The Canadian Press)
Noé Chartier

The senior Health Canada official who had final authority for the approval of the COVID-19 vaccines says the surveillance system to monitor its adverse events falls far short on providing an accurate picture of the situation.

“We do expect there to be a lot of underreporting,” said Dr. Celia Lourenco, acting associate assistant deputy minister with Health Canada, during a Federal Public Sector Labour Relations and Employment Board hearing on July 13.

The official approved the COVID-19 vaccines currently on the market in her previous role as director-general of the Biologic and Radiopharmaceutical Drugs Directorate in the department.

Dr. Lourenco said this underreporting is a “well-known fact,” because health-care professionals may not report the adverse events, or patients may not report it to a physician.

“It doesn’t get reported to the regulator, so that’s a common problem,” she said, adding that the phenomenon exists across countries.

Dr. Lourenco was being cross-examined as the board adjudicates cases where public servants who did not comply with the vaccine mandates were put on leave without pay and denied employment insurance benefits.

The Liberal government imposed a vaccine mandate on the public service and federally regulated sectors in October 2021 and abandoned it in June 2022.

Bernard Desgagné, who represents the grievor, Slim Rehibi, who worked for Employment and Social Development Canada, discussed the issue of underreporting and presented to Dr. Lourenco information on the U.S. system Vaccine Adverse Event Reporting System (VAERS), in which anyone can file a report.

He asked if Canada also has a similar adverse event underreporting issue as the United States. The U.S. Agency for Healthcare Research and Quality says that less than 1 percent of vaccination adverse events are reported to the Food and Drug Administration (FDA).

“Did Health Canada ever do a study to evaluate what would be the underreporting factor?” asked Mr. Desgagné. Dr. Lourenco did not answer directly.

Mr. Degagné remarked that if there’s indeed underreporting to that degree, the thousands of reports of deaths after COVID-19 vaccination in VAERS could mean there have been in fact millions of deaths.

VAERS has around 21,000 reports of deaths in relation to the COVID-19 vaccines as of July 7. The VAERS website notes that “Submitting a report to VAERS does not mean that healthcare personnel or the vaccine caused or contributed to the adverse event."

 Results from the VAERS database for a query on July 24, 2023, regarding deaths after COVID-19 vaccination. (Screenshot from VAERS).
Results from the VAERS database for a query on July 24, 2023, regarding deaths after COVID-19 vaccination. (Screenshot from VAERS).

The Epoch Times submitted a Freedom of Information Act request to the U.S. Centers for Disease Control and Prevention (CDC) to obtain the total number of VAERS-reported deaths following COVID-19 vaccination where the CDC assesses a causal link.

In a response obtained in June, the CDC said it has identified nine deaths that the Johnson & Johnson vaccine “caused or contributed to.”

The Public Health Agency of Canada (PHAC) says it has received 442 reports with an outcome of death following vaccination as of May. For a majority of the reports, PHAC says there’s missing information to assess causality, with only four identified as having a causal link.

Underreporting in Canada

Health Canada recognizes that the vast majority of adverse events from vaccination go unreported.

“Most pre pandemic studies about this topic estimate adverse drug reaction under reporting rates of 90% or higher,” wrote health department spokesperson Nicholas Janveau in an emailed statement.

He says reporting is “fundamental” for drug safety surveillance, but underreporting takes place in voluntary and mandatory reporting systems.

Mr. Janveau says there is no specific estimation of underreporting of adverse events following vaccination and that it will vary depending on context. It is normal for milder events to be less reported, he says, and for reporting to increase if there is heightened public awareness and media reporting.

PHAC says that as of May 26, 2023, it has received reports of 55,145 adverse events following immunization out of 98,194,601 COVID-19 vaccine doses administered (0.056 percent of all doses administered).
Out of those, 10,906 were deemed serious (0.011 percent of all doses administered). One report counts for one person, who could have reported multiple adverse events. Adverse event reports can be filed by doctors, nurses, or pharmacists.
Serious adverse events include deaths and situations that are life-threatening or require hospitalization.


Aside from the data it receives directly from provinces, PHAC has financed work by the Canadian Immunization Research Network on its Canadian National Vaccine Safety (CANVAS) network to monitor adverse events following immunization (AEFI).

CANVAS has monitored adverse events with surveys collecting data on the seven days post-COVID vaccination for first, second, and third doses.

The Epoch Times analyzed data collected by CANVAS that was released in an article published in the journal Clinical Infectious Diseases in March. It shows that for 1,173,748 COVID-19 vaccine doses administered and surveyed, there were 3,276 reported "serious health events" requiring an emergency department visit or hospitalization.

This represents one serious health event for every 358 doses, or 0.28 percent of all doses surveyed for the study.

The study states that “​​Medically attended events triggered a telephone call from a research assistant or nurse trained in eliciting AEFI information.”

The survey also collected responses on health events post-vaccination that prevented daily activities or required medical care. Results show there were 66,151 such events for 1,173,748 doses, or one event per 17 doses (5.64 percent of all doses administered and surveyed for the study).

The Epoch Times contacted the CANVAS project and its lead researcher, Dr. Julie A Bettinger, for comment but didn’t hear back by publication time.

The proportion of adverse events captured by CANVAS is much higher than what was reported to PHAC, but the collection methods differ.

“Survey-based measurements of adverse events such as the method used for CANVAS is expected to detect higher rates of mild events because these events are most common and least likely to be reported to the health care system or to passive surveillance systems,” says Health Canada’s Mr. Janveau.

Survey Results

Separate from the scientific article, CANVAS posted some survey results online last April that also point to the underreporting experienced by PHAC’s system.

Survey participants reported their health status after their first and second COVID-19 vaccination doses. CANVAS received a total of 1,430,125 survey responses, encompassing adults and children.

Instead of using the terminology employed by PHAC such as “adverse event” and “serious adverse event,” CANVAS uses the term “health event” to describe “any changes to your health after getting vaccinated, which may include worsening of an existing health condition.”

In total, for first and second doses among adults and children, around 50 percent reported “pain, swelling, or redness at the injection site.” PHAC considers these issues as adverse events, describing them as “Vaccination site pain,” “Vaccination site swelling,” “Vaccination site erythema (redness).” This alone, without considering other adverse events reported by CANVAS, dwarves the 0.056 percent reported by PHAC.

The study adds that 91 percent of adults didn’t develop another unspecified health event within seven days of receiving their first and second doses, and 95 percent didn’t experience a health event that “prevented daily activities, work or required a medical visit.”

The survey results say that the most frequently reported health events for adults were flu-like symptoms (4.6 percent first dose, 6 percent second dose), headache or migraine (3.4 percent first dose, 4.3 percent second dose), and nausea, vomiting, and diarrhea (2 percent first dose, 2.3 percent second dose).

For children, there were 378,463 doses received. Surveys completed showed that around 46 percent reported pain, swelling, or redness at the injection site, while 96 percent did not develop a health event preventing daily activities or requiring a medical visit for the first dose and 97 percent for the second dose.

The number of participants in the second-dose survey is around half the amount of those who took part in the first-dose survey.

CANVAS researchers explained their study in an article published in BMJ Open in January 2022. They note that the clinical trials for the COVID-19 vaccines before their authorization did not include enough participants to detect rare adverse events such as thrombosis, and did not include enough individuals with compounding conditions, such as advanced age or varying underlying health conditions.

The article also says that passive surveillance of adverse events “suffers from under-reporting and reporting bias.”