Pfizer vaccine 95% effective in final analysis, plans to seek emergency authorization 'within days'
Pfizer and partner BioNTech announced Wednesday that their COVID-19 vaccine candidate is more than 95% effective in the final analysis of its massive Phase 3 trial and has reached a key safety milestone that will allow the company to apply for authorization from the U.S. Food and Drug Administration "within days."
If the FDA gives the vaccine the green light, Pfizer will likely make history as the first company with an FDA-authorized COVID-19 vaccine. It has plans to start delivering millions of doses of the potentially lifesaving vaccine to the most vulnerable overnight once the government gives a green light, possibly before the end of 2020, the company said.
Just last week, Pfizer and BioNTech announced their vaccine was more than 90% effective, according to a preliminary analysis based on the first 94 patients to develop symptomatic COVID-19 in a trial of more than 43,000 volunteers.
But with the pandemic raging in the United States and across the globe, it didn't take long for even more volunteers to become infected, quickly bringing Pfizer's trial to 170 COVID-positive cases -- exceeding the threshold needed for a "final" analysis on the vaccine's effectiveness.
In a press release, delivered before the stock market opened, Pfizer announced that among the 170 volunteers to develop COVID-19 in the clinical trial, 162 had been given placebo shots, while only eight volunteers to become infected were given the real vaccine.
This means Pfizer's vaccine is roughly 95% effective at preventing symptomatic COVID-19. The updated efficacy data follows news from competitor Moderna, which announced earlier this week that its vaccine was 94.5% effective in its own preliminary analysis.
It’s not known yet what level of immunity or how long the immunity lasts after receiving the vaccines. Trial volunteers will be followed for two years to answer questions like durability of protection.
Pfizer also announced another major milestone Wednesday -- enough safety data to merit FDA authorization. The FDA requires at least two months of safety data among at least half of the trial volunteers before it will consider granting a limited emergency authorization. Pfizer has now hit key milestones that will allow the company to apply for this limited authorization, which could happen in the coming days.
ABC News' Sony Salman contributed to this report.