In this MD Newsline exclusive interview with Dr. Tom Shimabukuro of the CDC’s Immunization Safety Office, we discuss the CDC’s/FDA’s Vaccine Adverse Event Reporting System.
Some people are confused about how to interpret reports sent to the Vaccine Adverse Event Reporting System (VAERS). Could you elaborate on how VAERS works and how to interpret VAERS data?
Dr. Tom Shimabukuro:
“Let me walk you through the life cycle of a VAERS report. The timeline begins with a person getting vaccinated and experiencing an adverse health event. Then, the patient, parent, or healthcare provider reports that adverse event to VAERS. Some of these adverse events might be true adverse reactions caused by the vaccine, and some might be coincidental health events. VAERS cannot determine cause and effect.
But, it can monitor for unusual reporting patterns that may lead us to believe we have a potential safety problem. We refer to these data as safety signals. When we detect a safety signal, we do further assessment in the VAERS system to determine if that safety signal merits further evaluation. If it does, we can go to a more robust system like the Vaccine Safety Datalink to further assess whether or not that’s a true signal, and we can then characterize the risk if it is a true signal.
I think one of the biggest misconceptions about VAERS is that reports to VAERS equate to true adverse reactions. But, again, some of these reports to VAERS likely are true adverse reactions, and many of them are likely coincidental health events and not related to vaccination. Moreover, there are many reasons why there may be more reporting for COVID-19 vaccines, but that doesn’t necessarily mean that the rate of adverse reactions is higher.
Also, there’s been a lot of public awareness and media awareness of the immunization program, which can result in reporting biases. Lastly, the CDC has done a lot of education and outreach to providers to encourage them to report to VAERS. So these are some of the reasons why we think there’s been a lot of reporting of adverse events to VAERS for COVID-19 vaccines. However, when we look at the patterns of reports, they appear to be generally similar to those of other vaccines that are routinely administered in the United States.”
Responses have been condensed and lightly edited.