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FDA staff refuse to take position on third doses of Pfizer, citing lack of verified data

A person receives a dose of Pfizer-BioNTech’s coronavirus disease (COVID-19) vaccine, at a mobile inoculation site in Bronx, New York, August 18, 2021.

David ‘Dee’ Delgado | Reuters

Food and Drug Administration staff declined on Wednesday to take a position on whether to support Pfizer’s Covid-19 vaccine booster shots, saying U.S. regulators had not verified all available data.

“There are many potentially relevant studies, but the FDA has not independently reviewed or verified the underlying data or their conclusions,” they wrote in a 23-page document posted on the website. agency. “Some of these studies, including data from the vaccination program in Israel, will be summarized at the VRBPAC meeting on September 17, 2021.”

Staff said some observational studies have suggested a decrease in the effectiveness of the Pfizer vaccine over time against symptomatic infection or against the delta variant, while others have not.

“Overall, the data indicates that the COVID-19 vaccines currently licensed or authorized in the United States still provide protection against severe COVID-19 illness and death in the United States,” they wrote.

The data the FDA is looking at includes efficacy figures from Israel, where researchers have published observational studies showing that the effectiveness of the Pfizer vaccine against infection has declined over time.

In separate documents released on Wednesday, Pfizer argued that a third dose of the Covid vaccine six months after a second injection restores protection against infection to 95%.

FDA staff appeared to take a skeptical tone about the data, as the observational study does not meet the same standards as a formal clinical trial.

“It must be recognized that while observational studies can help understand effectiveness in the real world, there are known and unknown biases that can affect their reliability,” agency staff said. “In addition, US studies on the post-authorization efficacy of BNT162b2 may most accurately represent the efficacy of the vaccine in the US population.”

The staff report is intended to inform the FDA’s Vaccines and Related Biologics Advisory Committee, which is meeting on Friday to consider Pfizer’s request to approve Covid booster doses for the general public. The published documents provide an overview of the agency’s point of view on third shots.

The Biden administration has said it wants to start offering recalls to the general public as early as next week, pending FDA clearance. The move is part of President Joe Biden’s broader plan to deal with a higher number of Covid cases fueled by the fast-spreading delta variant.

Scientists and other health experts have repeatedly criticized the plan, saying the data cited by federal health officials was unconvincing, calling the administration’s recall request premature.

There is currently no consensus in the biomedical community on boosters for the general public, said Dan Barouch, immunologist at Harvard Medical School.

“There are high level experts who are on different sides of the debate,” he said. “For now, it will be interesting to see where the debate goes, but we obviously know that the Biden administration has suggested that boosters are needed.”

The Biden administration cited three studies, published by the Centers for Disease Control and Prevention, which showed that vaccine protection against Covid declined over several months. The administration plan, described by senior health officials, calls for a third dose eight months after people receive their second injection of the Pfizer or Moderna vaccine. Biden said scientists are considering whether to move the third shot by three months.

When the administration announced the plan in August, senior health officials said they feared protection against serious illness, hospitalizations and death “may” wane in the coming months, especially among those who are at higher risk or who were vaccinated during the early stages of the vaccination rollout.

A group of scientists, including two senior officials from the FDA and the World Health Organization, published an article in The Lancet on Monday, claiming that booster shots are not necessary for the general public at this time. . While the effectiveness of the Covid vaccine against mild illness may decline over time, protection against serious illness appears to persist, scientists said.

On Tuesday, WHO officials again called on rich countries to stop distributing booster doses of the Covid vaccine in hopes of making more vaccines available to poorer countries with lagging vaccination rates.

“There are countries with less than 2% vaccination coverage, most in Africa, which do not even receive their first and second dose,” Director-General Tedros Adhanom Ghebreyesus told a press briefing. starting with the boosters, especially giving them to healthy populations, is definitely not correct. “

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