Since the start of the COVID-19 vaccination campaign, millions of people have sought clear information about the safety and potential side effects of the vaccines. Posts circulating on social media claim that Pfizer has finally released a secret list of adverse reactions. However, this claim needs context.
The potential side effects of Cominnaty, the COVID-19 vaccine developed by Pfizer-BioNTech, were not kept secret. They were included in official documents intended for patients and healthcare professionals and were updated as authorities gathered new data.
As with any medicine, safety information is not static. It continues to be reviewed after authorization through clinical trials, medical reports, and pharmacovigilance systems.
What is the difference between a side effect and a reported event?
This point is essential to correctly understand the lists that circulate on the internet.
A recognized side effect is a reaction for which there is sufficient evidence of a possible link to the drug or vaccine. In contrast, a reported adverse event is any health problem that occurs after vaccination, even if the vaccine has not yet been proven to have caused it.
For example, if a person experiences a headache several days after vaccination, they can report it to the surveillance system. The report is recorded and must be analyzed, but its presence in a database does not automatically demonstrate a cause-and-effect relationship.
Regulatory bodies look for patterns, compare the frequency of problems between vaccinated and unvaccinated people, review medical histories, and study whether there is a reasonable biological explanation.
Therefore, a long list of reported events should not be presented as a list of diseases “caused by the vaccine”.
The most frequent side effects
