Pfizer Inc. said Tuesday that it has asked the U.S. Food and Drug Administration to approve the emergency use of a second booster shot for Americans 65 and older.

In a statement announcing its request, Pfizer relied on data from two studies out of Israel that have been published without peer review on pre-print servers.

The first study, conducted in concert with Israel’s Ministry of Health, reviewed the health records of 1.1 million people and concluded that they were less likely to become infected or develop severe illness after a fourth dose of Pfizer’s vaccine. However, Israel only recently began its second booster program, so it was unclear how long the extra protection might last. Israel began offering fourth doses to health care workers in late December, then quickly broadened eligibility to those 60 and older and other vulnerable groups.

The second study, of Israeli health care workers, showed that while fourth shots of either Pfizer’s or Moderna’s vaccine boosted antibody levels, it was not very effective at preventing infections. Researchers said those findings underscored the urgency of developing vaccines that target whatever variant is circulating.

Still, “both data sets showed evidence that an additional mRNA booster increases immunogenicity and lowers rates of confirmed infections and severe illness,” the company said in its statement.

Pfizer CEO Dr. Albert Bourla has said more than once in the past week that the company believes a fourth shot will be needed to counter the waning power of the third shot.

A meeting of an FDA expert advisory committee to discuss the issue of second booster shots is expected to be held next month, The New York Times reported.

While a fourth shot for all older Americans without weakened immune systems may be a good idea now, giving extra booster shots to the general population should probably be put on hold until the fall, some senior Biden administration officials suggest.

“Barring any surprises from new variants, maybe the best thing is to think about our booster strategy in conjunction with the influenza vaccine next fall, and get as many people as possible boosted then,” Dr. Peter Marks, the FDA’s top vaccine regulator, told the Times last month.

Any recommendation on a second booster shot would likely target people most at risk, possibly based on underlying conditions as well as age, Dr. Anthony Fauci, chief medical adviser to the White House, has said.

In addition, the administration is running short on funds for COVID vaccines, a senior White House official told reporters on condition of anonymity Tuesday, the Times reported. The official said there is enough money to cover fourth shots for people with weakened immune systems, but additional funding from Congress would be needed to pay for second boosters for all Americans.

A U.S. Centers for Disease Control and Prevention study released last month showed that protection began to weaken after a booster shot of either the Pfizer or Moderna vaccine, but it did not analyze cases by age, immune deficiencies or underlying health conditions.

More information

Visit the U.S. Food and Drug Administration for more on COVID boosters.

Source: HealthDay

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