In August, U.S. health officials said they would make a third dose of the Pfizer vaccine available starting on September 20. File Photo by Bill Greenblatt/UPI | License Photo
Sept. 15 (UPI) -- Scientists at the Food and Drug Administration said in a document on Wednesday that a third dose of Pfizer's COVID-19 vaccine increases protection against the disease, but stopped short of recommending that all Americans receive the booster shot.
In August, U.S. health officials said they would make a third dose of the Pfizer vaccine available starting on Sept. 20, mainly as a result of the Delta coronavirus variant, which is more infectious than the original strain.
President Joe Biden has also endorsed a third dose for people who received the original two-dose Pfizer vaccine. Some experts, however, have said it might still be too early to know for sure if the bulk of the public should seek a third dose.
Wednesday, the FDA scientists echoed that caution, saying a third dose appears to activate a greater immune response -- but added that there's no evidence yet to signal that another shot is widely needed.
"There are many potentially relevant studies, but FDA has not independently reviewed or verified the underlying data or their conclusions," the agency said, according to CNBC.
The scientists noted that some studies suggest the Pfizer vaccine declines in effectiveness over time, and some do not. They also said they're looking at studies from Israel that have shown decreasing effectiveness.
Also Wednesday, the FDA released a report by Pfizer that recommends a third dose.
Pfizer's advice leans on U.S. and Israeli vaccine data that suggests the vaccine'd protection "wanes" between six and eight months after the second dose.
The FDA's vaccines committee is scheduled to meet on Friday to discuss authorizing a third dose of the Pfizer coronavirus vaccine, which the pharma company has named Comirnaty, for all recipients over the age of 16.