- Pfizer’s coronavirus vaccine candidate was 95% effective at protecting people against COVID-19 in its late-stage trial, the pharmaceutical giant said in a Wednesday press release.
- Pfizer shared preliminary results from the study on November 9. Wednesday’s release provided more details that come from the trial’s final efficacy analysis.
- Pfizer began developing the experimental shot in March with the German biotech BioNTech.
- No data from the late-stage trial has been published in a medical journal yet.
- The companies plan to apply for emergency use authorization in the US “within days.”
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On November 9, the world learned that Pfizer’s coronavirus vaccine was found to be highly effective.
Though details were sparse in that release, the news that the vaccine was highly protective against COVID-19 showed a potential exit path from this pandemic.
The finding came from a 43,661-person trial that randomised volunteers to get two doses of either Pfizer’s shot or a placebo. The initial analysis was based on 84 COVID-19 cases.
On Wednesday, Pfizer and its German partner BioNTech released updated results from their final-stage clinical trial with more detailed information. The results have not yet been published in a medical journal.
The release said the vaccine was 95% effective against COVID-19. That’s based on 170 cases of COVID-19 seen in the study, with 162 of those illnesses happening among people who got a placebo. Pfizer said the vaccine was similarly effective in older people and in people of different races and ethnicities.
Pfizer’s shot isn’t the only one with promising late-stage results. The biotech company Moderna said on Monday that its shot appeared to be 94.5% effective against COVID-19, based on a preliminary analysis of its final trial.
Vaccine could also prevent severe disease and showed no serious safety issues
Pfizer’s results also suggest the shot helps prevent severe disease, with the study tallying 10 cases of severe COVID-19. Nine of those cases occurred in the placebo group.
There were no serious safety problems, Pfizer said. The most common severe side effect was fatigue, with 3.8% of participants registering levels high enough to prevent daily activity. 2% of people also had severe headaches. Pfizer said most side effects resolved shortly after vaccination.
Participants in Pfizer’s trial appeared to report fewer severe side effects than volunteers who got Moderna’s shot; 9.7% of those who got the Moderna shot reported severe fatigue, and people also reported aches and pains and headaches as well.
There’s still a lot we don’t know about Pfizer’s shot. It’s not clear how long the protection from the shot will last, and we also don’t know whether the shot will stop vaccinated people from being asymptomatic carriers of the coronavirus.
Pfizer plans to apply for emergency OK ‘within days’
Pfizer and BioNTech also said they’d collected enough safety data from the study to apply for emergency-use authorization in the US, which would allow the shots to be given more widely. The companies said they “plan to submit within days.”
BioNTech CEO Ugur Sahin later told CNN that the companies plan to submit the paperwork on Friday.
That will turn all eyes to the US Food and Drug Administration, which is responsible for reviewing and approving medicines. Dr. Peter Marks, who’s in charge of the FDA’s review of coronavirus vaccines, told Business Insider on Friday that it would take weeks to vet a COVID-19 shot.
Even if a vaccine is authorised, doses will be extremely limited at first. US government officials have estimated that about 20 million people could be immunized in December, with that number modestly ramping up each month as more production capacity comes online.
Top government scientists have estimated a vaccine will probably be widely available in the US sometime next spring or early summer. Until then, masks and social distancing remain society’s most valuable measures to combat the raging pandemic.
This story has been updated with new information from Pfizer on the vaccine’s side effects.