Fact Check – Suspected Side Effect Pages Posted About Pfizer’s COVID-19 Vaccine ‘May Not Be Causally Linked’ To Vaccine, Company Says

Nine pages of adverse event reports from Pfizer-BioNTech regarding its COVID-19 vaccine are not confirmed adverse events for the vaccine. They “may have no causal relationship” to each other, the drug company told Reuters. The statement comes in response to claims online that the list is final.

The document was submitted by Pfizer as part of its Biologics License Application (BLA) to the US Federal Drug Administration (FDA) (here).

It compiled data from 63 countries such as the US, UK, Italy, Germany and France received between December 1, 2020 and February 28, 2021 – and includes nine pages of “events undesirables of special interest”.

Examples of such events are labored breathing, deja vu and myocardial infarction, as well as 1,223 events with a fatal outcome (here).

Some people on social media have since concluded that every entry is definitely caused by Pfizer’s COVID-19 vaccine.

A post, which includes screenshots of all nine pages (here) and has been shared hundreds of times, reads: “Among these newly posted pages are 9 PAGES OF ADVERSE SIDE EFFECTS! The list includes autoimmune diseases, countless heart problems, hemorrhages, kidney disease, many syndromes transmitted to other viruses and even anti-sperm antibodies!Safe and effective, right…? »

Similar posts can be seen on Facebook (here, here, here, here and here)) and Twitter (here and here).

However, the list was compiled using voluntary reports through various national reporting systems, such as the US Vaccine Adverse Event Reporting System (VAERS), the UK Yellow Card Reporting System and EU’s EudraVigilance database.

Reuters has carried out numerous fact checks on these systems (VAERS: here and here; Yellow Card: here and here); EudraVigilance here and here) – all of which explain that reports of potential side effects are not definitively linked to vaccines.

A Pfizer spokesperson told Reuters the reported side effects “may not be causally related to the vaccine”, adding that all reports are taken “very seriously”.

“Rather, the event may be due to an underlying disease or some other factor such as medical history or concurrent medications or the AEs (adverse events) may be coincidental,” they said.

ARs are collected for all of Pfizer’s products, including its COVID-19 vaccine, to monitor safety issues that may not have been flagged in clinical studies.

The spokesperson explained that the company has “robust processes” in place to assess each product’s potential safety risks and to ensure that post-clearance responsibilities are met.

“In addition to our pharmacovigilance efforts and meeting various regulatory requirements related to quality and safety, we also cooperate with the FDA and regulatory authorities around the world as they independently monitor the safety profile of our vaccine. “, they said.

An FDA spokesperson told Reuters that reports to VAERS after vaccination “do not necessarily mean that a vaccine caused a health problem” – and anyone can submit a report, regardless of their plausibility.

The FDA spokesperson added, “In fact, FDA and CDC reviews have determined that the vast majority of reported deaths are not directly attributable to vaccines. The FDA requires health care providers to report any deaths after COVID-19 vaccination to VAERS, even if it is unclear if the vaccine was the cause.

They also explained that VAERS is an “early warning system” that is used to establish any problems with vaccines or drugs that may have been missed before they were licensed. This means that Pfizer would not have been aware of the suspected side effects before obtaining the authorization.

Similarly, a spokesperson for the European Medicines Agency (EMA) told Reuters that reports of suspected side effects from COVID-19 vaccines by patients and healthcare professionals “are not necessarily related or caused by the vaccine”.

“Spontaneous case reports of suspected adverse reactions are rarely sufficient to prove that a certain suspected reaction was indeed caused by a specific drug. It may be a symptom of another disease or be associated with another medication taken by the patient at the same time. Therefore, a case report should be viewed as one piece of a puzzle.

They added: “For most medications, the vast majority of suspected side effects are ultimately not confirmed as side effects.”


Missing context. The nine pages of “adverse events of special concern” are not confirmed side effects of Pfizer’s COVID-19 vaccine.

This article was produced by the Reuters Fact Check team. Learn more about our fact-checking work here.

Calvin W. Soper