The staff of the U.S. Food and Drug Administration on Wednesday declined to take a stance on whether to back booster shots of Pfizer’s (NYSE:PFE) COVID-19 vaccine, saying U.S. regulators haven’t verified all the available data.
"There are many potentially relevant studies, but FDA has not independently reviewed or verified the underlying data or their conclusions," they wrote in a 23-page document published on the agency’s website. "Some of these studies, including data from the vaccination program in Israel, will be summarized during the September 17, 2021 VRBPAC meeting."
The staff said some observational studies have suggested declining efficacy of the Pfizer vaccine over time against symptomatic infection or against the delta variant, while others have not.
"Overall, data indicate that currently US-licensed or authorized COVID-19 vaccines still afford protection against severe COVID-19 disease and death in the United States," they wrote.
The data the FDA is looking at includes efficacy numbers out of Israel, where researchers there have released observational studies showing the effectiveness of the Pfizer vaccine against infection waned over time.
In separate documents released Wednesday, Pfizer argued a third dose of the COVID vaccine six months after a second shot restores protection from infection to 95%.
FDA staff appeared to take a skeptical tone on the data, as observational studies don’t adhere to the same standards as formal clinical trials.
PFE shares began Thursday down 14 cents to $44.63
