FDA last week released 55,000 pages of review documents for Pfizer-BioNTech's Covid-19 vaccine, which some experts say may lead to "cherry picking and taking things out of context" when it comes to vaccine efficacy and safety.

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Lawsuit expedites FDA's release of vaccine data

In September, Public Health and Medical Professionals for Transparency sued FDA, claiming the agency denied a request to expedite the release of Pfizer-BioNTech's Covid-19 vaccine review documents via the Freedom of Information Act (FOIA).

In response to the lawsuit, FDA in November proposed releasing around 500 pages of the review documents each month—which would fulfill the organization's FOIA request in around 55 to 75 years. FDA said the agency branch responsible for handling the request has only 10 employees and is currently processing 400 other FOIA requests, MedPage Today reports.

However, U.S. District Judge Mark Pittman of the Northern District of Texas in January issued a court order requiring FDA to significantly speed up the release of the documents.

Under the court order, FDA was required to release approximately 12,000 pages of documents immediately, and then 55,000 pages a month until all documents—totaling more than 300,000 pages—are released. Before the documents can be released, the agency must redact confidential business and trade secret information from Pfizer and BioNTech, as well as private patient information from clinical trials.

Although the court noted that releasing this many documents this quickly would have "unduly burdensome challenges" for FDA, it said releasing the documents is of "paramount public important" and expediting the process is "not only practicable, but necessary."

According to Zach Zalewski, a regulatory strategy consultant at Avalere Health, the released documents will "literally include every scrap of paper that was submitted to FDA for the entirety of the pandemic," but they are not likely to be useful in determining the vaccine's overall safety and efficacy.

However, this has not stopped anti-vaccine advocates from using the released documents to question the safety of Covid-19 vaccines, MedPage Today reports. For example, Children's Health Defense, a nonprofit that advocates against the use of Covid-19 vaccines in kids, highlighted a list of adverse events that occurred during clinical trials of the vaccine—a list experts have said is misleading since it also includes adverse events that occurred in participants who received a placebo.

With the release of these documents, "[t]here's a risk of cherry picking and taking things out of context," Zalewski said. "Just because you will have all the data in front of you, that doesn't mean you'll reach any different conclusions."

Data supports safety of mRNA Covid-19 vaccines

Currently available data indicates that the Covid-19 vaccines from both Pfizer-BioNTech and Moderna have largely been safe for recipients.

In a CDC study published in Lancet Infectious Diseases, researchers examined self-reported data from the Vaccine Adverse Event Reporting System (VAERS) and v-safe tracker.

Of the 340,522 reports made to VAERS, 92% were non-serious, 6.6% were serious, and 1.3% were deaths. The most common adverse events reported for both vaccines were headaches (20%), fatigue (17%), and fever (16%). Among the serious adverse events, shortness of breath (15%) was the most commonly reported for both vaccines.

Similarly, headache (56%) and fatigue (46%) were the most commonly reported symptoms among participants in the v-safe tracking system. In addition, around two-thirds of participants reported injection site pain after their vaccine doses. Overall, less than 1% of participants said they sought medical care for adverse events after vaccination.

The researchers also found that women and individuals ages 65 and younger were more likely to report adverse events after vaccination, leading them to suggest that "mild-to-moderate transient reactogenicity should be anticipated, particularly among younger and female vaccine recipients."

According to the study authors, there were several limitations to their findings, including potential underreporting to both v-safe and VAERS, limited death and autopsy data, and the fact that self-reported VAERS data alone "generally cannot establish causal relationships between vaccination and adverse events."

However, Hannah Rosenblum, a CDC researcher and one of the study's authors, said that, overall, "Covid-19 vaccine safety monitoring is the most robust in U.S. history and the two complementary surveillance systems used in this study should bolster confidence that mRNA Covid-19 vaccines are safe."

Similarly, Matthew Krantz and Elizabeth Phillips, both from the Vanderbilt University School of Medicine, wrote in an accompanying editorial that the report's findings were "reassuring" and that "there were no unexpected signals other than myopericarditis and anaphylaxis, already known to be associated with mRNA vaccines." (D'Ambrosio, MedPage Today, 3/7; Walker, MedPage Today, 3/7)