Thousands of people have been unable to work or perform daily activities, or required care from a health care professional, after getting the new COVID-19 vaccine, according to new data from the Centers for Disease Control and Prevention (CDC).
As of Dec. 18, 3,150 people reported what the agency terms "health impact events" after getting vaccinated.
Those who are experiencing these "events" are "unable to perform normal daily activities, unable to work," or "required care from [a] doctor or health care professional."
The incidents were reported through V-safe, a smartphone application. The tool uses text messages and web surveys to provide personalized health check-ins, and allows users to quickly tell the CDC if they're experiencing side effects.
The CDC and Pfizer, which produces the vaccine with BioNTech, didn't immediately respond to request for comments.
The CDC said that 272,001 doses of the vaccine were administered as of Dec. 19. That means most people who were vaccinated didn't experience negative effects.
The CDC has identified six case reports of anaphylaxis, or severe allergic reaction, that occurred following vaccination with the new vaccine, Clark reported. Other case reports were reviewed and determined not to be of anaphylaxis.
Anyone who experiences anaphylaxis after getting the first vaccine should not get the second shot, the CDC said. COVID-19 vaccines are meant to be given across two doses, spaced about three weeks apart.
Dr. Peter Marks, director of the Food and Drug Administration's Center for Biologics Evaluation and Research, told reporters in a call on Dec. 17 that the agency is working with the CDC and colleagues in the UK on probing the allergic reactions.
"We'll be looking at all of the data we can from each of these reactions to sort out exactly what happened. And we'll also be looking to try to understand which components of the vaccine might be helping to produce them," he said.
Noting that he was speculating, Marks said it's known that polyethylene glycol—a component present in both the Pfizer vaccine and one from Moderna that regulators approved earlier in the day—can be associated, uncommonly, with allergic reactions.
"So that could be a culprit here. And that's why we'll be watching very closely," he said. "But we just don't know at this point."
Both vaccines have "systemic side effects," which are "generally mild," Marks said. They go away after a day. According to the FDA website, the most commonly reported side effects include tiredness, headache, muscle pain, and chills. The agency said they go away after several days.
One volunteer in Pfizer's late-stage clinical trial experienced an allergic reaction. Two people in Moderna's phase three clinical trial experienced anaphylactic reactions, the company said during a meeting on Dec. 17. But the data showed the benefits outweigh the risk, FDA officials said, as they granted emergency use authorization to the vaccines about seven days apart.
People who get a COVID-19 vaccine should be monitored for at least 15 minutes after getting vaccinated, according to the CDC.
If someone experiences a severe allergic reaction to getting a COVID-19 vaccine, vaccination providers are supposed to provide rapid care and call for emergency medical services. The person should continue to be monitored in a medical facility for at least several hours.