The drug maker Pfizer and its German partner BioNTech applied on Friday to the Food and Drug Administration for an emergency use authorization for their Covid-19 vaccine, a watershed moment in the effort to curb the global pandemic.
Hours later, the FDA announced that a panel of outside experts, the Vaccines and Related Biological Products Advisory Committee or VRBPAC, will meet Dec. 10 to review the data and advise the agency on whether to approve the emergency use request and what conditions, if any, to put on the vaccine’s use. It it unlikely to be authorized for use in children under the age of 12, for instance, because it hasn’t yet been tested in pre-teens.
It is widely expected that the FDA will then issue an emergency use authorization for the two-dose vaccine, which has been shown to be highly effective in preventing Covid infections. Officials have said they hope to begin vaccination of health workers — who will be at the front of the line for the limited first doses — in some locations within days of the authorization.
At an earlier meeting of VRBPAC, in late October, FDA officials seemed to signal they were rethinking the idea of using an EUA to allow early use of Covid vaccines, indicating that to do so might disrupt other ongoing clinical trials and limit the ability to generate sufficient data about the various vaccines. Instead, officials indicated they were considering using expanded access protocols to allow the vaccines to be used.
It appears, though, that that trial balloon did not fly. At a public forum this week, Marion Gruber, director of FDA’s Office of Vaccines Research and Review, suggested expanded access is now off the table.
“It is likely … that an emergency use authorization request will be submitted by the vaccine manufacturer,” she said during the forum, referring to the Pfizer-BioNTech product. “And if supported by the data, the FDA is likely to issue an EUA for this vaccine.”
In the Pfizer vaccine’s Phase 3 trial, which enrolled 43,661 volunteers, 170 people developed symptomatic Covid infection. Of those, 162 were in the placebo arm of the trial and only eight received the vaccine. There were 10 cases of severe infections in the trial, nine of which were in the placebo group, which suggests that the vaccine protects against serious disease as well as mild illness. Overall, the vaccine was shown to be 95% effective in preventing symptomatic Covid infection.
“When I heard the over 90% efficacy, I felt I was living a dream,” CEO Albert Bourla said Tuesday during an interview at the STAT Summit.
The U.S. government has an agreement to purchase 100 million doses of the vaccine, with an option to purchase an additional 500 million doses. Pfizer projects that it will be able to provide 25 million doses in December — enough to vaccinate 12.5 million people.
Moderna, also a frontrunner in the race to develop Covid-19 vaccine, announced Monday that a preliminary analysis of its vaccine suggested it was 94.5% effective at preventing symptomatic infection. Of the 95 cases in the analysis, 90 were people who had received a placebo injection. Of the 11 severe cases seen to that point in the trial — which is ongoing — all were in the placebo arm.
The U.S. government expects to take receipt of another 15 million doses of vaccine from Moderna in December, which is enough to vaccinate an additional 7.5 million people.
Both vaccines use a new approach to coax the immune system to develop weapons with which to fend off the SARS-CoV-2 virus, which causes Covid-19. They are made using messenger RNA, or mRNA, which works by giving cells a recipe to produce a protein located on the exterior of the SARS-2 virus, the spike protein.
The spike protein — the knobby protrusions that surround the virus — allow the virus to attach to and invade cells in the respiratory tract. By triggering production of the spike protein, the vaccine teaches the immune system to be on the lookout for the virus.
The studies conducted to date do not indicate how long protection from the vaccines will last. But the high efficacy rates came as a welcome surprise; even Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, admitted he had not been anticipating efficacy estimates in the over 90% range.
“I’d like to say I would have predicted it, but I would not have,” Fauci told STAT.
Editor’s note: This story was updated with the news that Pfizer and BioNTech had formally submitted their application to the FDA.