In-Depth: Pfizer makes its case for boosters ahead of key FDA meeting, regulators remain skeptical

Pfizer COVID-19 vaccine
Posted at 6:18 PM, Sep 15, 2021
and last updated 2021-09-16 00:24:32-04

SAN DIEGO (KGTV) -- The Food and Drug Administration’s vaccine advisory committee will meet Friday to vote on whether to recommend booster shots for people who got the Pfizer vaccine.

Both Pfizer and Moderna have pushed regulators to approve third doses, citing research that shows evidence of waning protection six months or more after the second dose.

In documents released Wednesday ahead of the meeting, Pfizer cited newly published data showing the third dose of its vaccine boosted protection for older adults in Israel back up to about 95 percent.

However, FDA regulators expressed skepticism of the need for boosters in the first place.

FDA staff noted that some studies show evidence of reduced protection over time, while others have not. “However, 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,” regulators wrote.

This week, two high-ranking FDA officials announced plans to resign from the agency amid friction with the White House over the COVID booster plan. Last month, President Joe Biden announced plans to broadly roll out vaccine boosters beginning Sept. 20 before the FDA or Centers for Disease Control and Prevention had approved them.

The two departing officials co-wrote an article published in The Lancet on Monday. Dr. Marion Gruber, the director of the FDA’s Office of Vaccines Research and Review, and her deputy, Dr. Philip Krause, argued there is not yet a need to begin deploying boosters in the general population based on the latest evidence.

Decisions on boosters should be informed by “reliable science more than by politics,” they wrote.

In its application for a third dose, Pfizer acknowledges most studies show two doses remain more than 90 percent effective against severe disease, arguably the most important metric. But the company highlighted a small and troubling sample of data from Israel.

An analysis by Israel’s Ministry of Health found protection against severe disease dropped to less than 60 percent in some adults over 65 between Jun. 20 and Aug. 7. Those adults had been vaccinated for six months or more, beginning in January or February.

The vaccine was more than 80 percent effective against severe disease in seniors who were more recently vaccinated in March.

A peer-reviewed study in the New England Journal of Medicine published Wednesday afternoon showed adults 60 and older in Israel who got a third dose were 11.3 times less likely to have an infection. The booster lowered the rate of severe illness in those adults by a factor of 19.5.

FDA staff said data from Israel would be summarized at Friday’s meeting. Regulators noted that observational studies such as the one in Israel are not the same as controlled experiments and might have complicating factors or biases that affect reliability.

“I think they will probably approve a booster, but for a specific population,” said UC San Francisco infectious disease expert Dr. Peter Chin-Hong. He said the most likely group to get authorized will be adults over 65.

“I think we probably don’t want to take a chance with the older population because that’s the group that we were most fearful about,” he added.

Dr. Christian Ramers, an infectious disease specialist at Family Health Centers of San Diego, agreed that regulators would likely authorize boosters in a narrow group.

“I don’t actually think that we’re going to have this blanket recommendation for the entire country to receive a booster dose at this point,” he said.

The new booster program announced by the United Kingdom might offer a blueprint, Ramers said. The UK will offer third doses in stages to people over 50, frontline healthcare workers, people in nursing homes, and anyone with significant underlying conditions.

The FDA’s vaccine advisory committee will meet Friday to vote on whether to recommend Pfizer’s booster shot. The vote isn’t binding, but the FDA usually follows the group’s advice.