Vincent Kalut / Photonews via Getty Images
Pfizer’s coronavirus vaccine showed no safety concerns that could threaten an emergency authorization, regulators at the US Food and Drug Administration wrote in documents released Tuesday.
The detailed data indicates Pfizer’s shot is a highly effective and safe vaccine, based on a clinical trial of more than 40,000 participants.
There were temporary side effects that are generally expected with most vaccines. Common side effects were pain at the injection site, fatigue, and headaches.
An expert panel convened by the FDA is set to meet Thursday to discuss Pfizer’s application for an emergency OK. The agency’s decision could come shortly after.
For more stories like this, sign up here for Business Insider’s daily healthcare newsletter.
US vaccine regulators on Tuesday released the most detailed look yet at Pfizer’s coronavirus vaccine, outlining its safety and the side effects seen in a massive clinical trial.
Overall, the findings were positive, with the study suggesting no major safety concerns for Pfizer’s vaccine. Most immunized volunteers had temporary side effects shortly after being vaccinated, including fatigue, headaches, and pain at the injection site.
The US Food and Drug Administration is reviewing the COVID-19 shot for emergency use authorization, with a decision expected in a matter of days. An expert panel is set to meet Thursday to review Pfizer’s application and recommend a decision to FDA regulators.
Pfizer and BioNTech, its German biotech partner, tested their vaccine in a global study that randomized more than 40,000 volunteers to either get two doses of its vaccine or two doses of a placebo injection.
While Pfizer said it had enough data to show its vaccine was about 95% effective at preventing COVID-19, the company had to wait until November 20 to submit its application to accrue enough safety information. The FDA asked for at least two months’ worth of follow-up data on more than half the volunteers who received their second dose.
Read more: How the pharma giant Pfizer teamed up with a little-known biotech to develop an effective coronavirus vaccine in record time
Common side effects included fatigue and headaches
People under 55 years old reported more side effects. These side effects were expected with a vaccine, typically appearing within a couple of days of receiving a dose and lasting for only a day or two on average.
In their own summary of the data, FDA scientists said there were “no specific safety concerns identified that would preclude issuance” of an emergency use authorization.
Common side effects people reported after getting Pfizer’s vaccine were:
Pfizer and the FDA also provided information on the severe side effects that volunteers experienced. In general, those are side effects that are so bad that they stop people from performing normal activities.
Most of the severe side effects occurred after participants got the second dose, and side effects were more common among younger participants.
Among people aged 18 to 55, 4.6% reported severe fatigue after getting their second injection, and 3.2% had severe headaches.
Fevers were also common in that age group; about 15.8% of the volunteers had a fever of at least 100.4 degrees Fahrenheit after their second shot.
Among volunteers older than 55, 2.8% reported severe fatigue, 0.5% experienced severe headaches after the second dose, and 10.9% had a fever.
Scientists at the FDA and at Pfizer and BioNTech have been poring over the data to see whether there were any unexpected safety concerns. Encouragingly, they said in the documents released Tuesday that they didn’t find anything that caused concern.
FDA regulators noted a “numerical imbalance” in cases of Bell’s palsy, a condition that temporarily weakens face muscles: There were four cases of Bell’s palsy among the 20,000-plus people who got Pfizer’s vaccine, compared with no cases in the placebo group.
But the FDA said this frequency of Bell’s palsy cases among those who got Pfizer’s shot was not any higher than what would be expected for the general population.
Agency scientists also said that the vaccine’s safety profile was “generally similar” across different ages, genders, ethnicities, racial groups, as well as across people with or without health conditions and people with or without evidence of a previous coronavirus infection at enrollment. The only exception, they said, was that younger people tended to have more frequent side effects.
Read more: Moderna’s ambitions of pumping out up to 1 billion doses of a coronavirus vaccine rest on a former Polaroid factory that’s never produced an approved drug
Read the original article on Business Insider