CDC: With nearly 5 million Americans vaccinated, just 29 have had confirmed allergic reactions

CDC: With nearly 5 million Americans vaccinated, just 29 have had confirmed allergic reactions
Diana Carolina, a pharmacist at Memorial Healthcare System, receives a Pfizer-BioNtech Covid-19 vaccine at Memorial Healthcare System, on December 14, 2020 in Miramar, Florida.Joe Raedle/Getty Images
  • The CDC has released its first set of data about the safety of COVID-19 vaccines.
  • So far, only 29 people of the 5 million vaccinated have had confirmed, allergic reactions after vaccination in the US.
  • "Our vaccine safety systems haven't picked up any worrisome signals," the CDC's Nancy Messonnier said on a call with reporters Wednesday.
  • People with a history of anaphylaxis should wait 30 mins after vaccination before heading home, to make sure they're OK.
  • The only adults the CDC is recommending should NOT get vaccinated are those who've had a severe reaction after a previous COVID-19 shot.

The odds of a severe allergic reaction after COVID-19 vaccination are looking quite slim.

According to the first data released on allergic reactions after vaccination from the US Centers and Disease Control, only 29 cases of confirmed anaphylaxis have been reported among the 5 million Americans who have so far received shots from Moderna or Pfizer.

"Our vaccine safety systems haven't picked up any worrisome signals," the CDC's Nancy Messonnier said on a call with reporters on Wednesday. "This means that right now, the known and potential benefits of the current COVID-19 vaccines outweigh the known and potential risks of getting COVID-19."

The CDC is keeping track of bad vaccine reactions in a few different ways. One is a new texting system they're using to ask patients about symptoms, after they receive their first (of two) shots. This new self-reporting goes hand in hand with the existing Vaccine Adverse Events Reporting System (VAERS), which is co-managed by the CDC and FDA.

The only adults the CDC is so far recommending should not take a COVID-19 vaccine dose are those who have a bad reaction after their first shot.


Everyone else should be OK to get a vaccine, when it's their turn. But, people with a history of severe allergies may want to exercise some extra caution, the CDC said, and talk to the person administering their vaccine, before they get it.

This is the first comprehensive report on reactions

CDC: With nearly 5 million Americans vaccinated, just 29 have had confirmed allergic reactions
Healthcare workers get the Pfizer-BioNTech COVID-19 vaccination at the Legacy Emanuel Medical Center on December 16, 2020 in Portland, Oregon.Paula Bronstein/Getty Images

More than 350,000 people have died from COVID-19 across the US so far, and roughly 2,000 more are dying every day.

Both Moderna and Pfizer's shots started going into the arms of healthcare workers and elderly Americans in late December.

Though there have been scattered news reports about severe allergic reactions after vaccination both in the US and in the UK, the CDC's new report is the first comprehensive tally of confirmed anaphylactic reactions after COVID-19 vaccination in the US.

These reported reactions took place in the first week and a half of vaccine distribution, from December 14-23, when Pfizer's vaccine was becoming available to healthcare workers and nursing home residents across the country.


In the weeks since then, the CDC has confirmed at least an additional eight anaplylaxis cases, with at least one happening after administration of the Moderna vaccine, for a total of 29 reactions nationwide.

Allergic patients should talk to their vaccinator, and wait 30 minutes before heading home

The data suggest that allergic reactions after vaccination are exceedingly rare, but there were some trends.

Among the 21 people who had anaphylaxis after those initial shots in December, four had a past history of allergies to sulfa drugs, and two had egg allergies. Four patients had no history of allergies at all, and the majority had never had an anaphylactic reaction to anything before, making it tough to draw firm conclusions about what might've caused these occurrences.

Most of the reactions happened within 15 minutes after vaccination, which is why the CDC is recommending that providers have epinephrine at the ready (for treating allergic reactions) on site with vaccines.

Among the 21 cases the CDC recorded, 19 patients received epinephrin injections. At least four patients were hospitalized, with issues including wheezing, allover rashing, and in at least one case, some difficulty breathing, but all of them recovered.


"It's important that anybody who has had anaphylaxis talk to their vaccinator about that, and make sure that if they choose to be vaccinated, they wait the 30 minutes," Dr. Thomas Clark, who's been tracking allergic reactions after vaccination at the CDC said on the call.

"You know, many, many people with histories of allergies were vaccinated uneventfully."

That being said, the rate of anaphylaxis after COVID-19 vaccination, at about 11.1 cases per 1 million doses, is roughly 10 times higher than with flu vaccines.

"The anaphylaxis rate per COVID-19 vaccines may seem high compared to flu vaccines, but I want to reassure you that this is still a rare outcome," Messonnier said.

Dr. Paul Offit, a vaccine expert who served on the independent advisory committee to the FDA for both Pfizer and Moderna's vaccine authorizations, says it's important that both the FDA and CDC continue monitoring the safety of these new vaccines, but it's also critical not to fall victim to "the tyranny of small numbers" and conclude a relationship between rare issues (like bell's palsy) and the vaccine just yet.


"While a health event may happen after getting vaccinated, the vaccine isn't always the cause of it," Messonnier said.

Do you have a story to share about getting the vaccine? Contact public health reporter Hilary Brueck by email.