Several studies support COVID-19 vaccine boosters as FDA remains neutral ahead of Friday vote

Several studies published Wednesday supporting potential use of Pfizer's COVID-19 vaccine booster shot amid waning immunity met a neutral tone from the Food and Drug Administration, per documents posted ahead of a critical meeting Friday.

"Some observational studies have suggested declining efficacy of COMIRNATY [Pfizer's approved vaccine] over time against symptomatic infection or against the Delta variant, while others have not," an FDA briefing document reads, noting that current vaccines still offer protection against severe COVID-19 disease and death in the U.S.

"There are many potentially relevant studies, but FDA has not independently reviewed or verified the underlying data or their conclusions," the document continues. "It should be recognized that while observational studies can enable understanding of real-world effectiveness, there are known and unknown biases that can affect their reliability. Due to these biases some studies may be more reliable than others."