WASHINGTON — Are some people allergic to the COVID-19 vaccines? On social media, we have seen several claims of people having a severe allergic reaction when they get one of the COVID-19 vaccines.
Question:
Have people had an allergic reaction to the Pfizer and Moderna vaccines?
Answer:
Yes, in very rare cases.
Our Sources:
Dr. William Moss, a vaccines expert from Johns Hopkins University. Dr. Bruce Walker, an immunology expert from Harvard Medical School and the Centers for Disease Control and Prevention (CDC).
What We Found:
All of our sources said, yes.
“This happened with both the Pfizer and the Moderna vaccine, it was not a reaction that was seen in the phase three trials,” Dr. Moss said.
According to a January CDC study, 10 people out of 4 million had severe allergic reactions to the Moderna vaccine. Compared to the Pfizer vaccine, there 21 severe allergic reactions among 1.8 million doses given.
The study also found the majority happened almost immediately after getting the shot.
“It’s the reason why that after people receive the mRNA vaccines, they're being monitored for half an hour,” Dr. Walker said. “Because it overwhelmingly happens in that first 15 or 20 minutes after vaccination.
“Every site that delivers a vaccine needs to be able to handle these kinds of severe allergic reactions,” Dr. Moss added.
What is causing these extremely rare allergic reactions? Experts are still trying to figure it out.
“The leading hypothesis is that it's due to the mRNA of the Pfizer and Moderna vaccines is wrapped in kind of this fatty coat lipid coat that protects it,” Dr. Moss explained.
“Or it may be the solution that the that the lipid nanoparticles are in within the vial,” Dr. Walker said.
But, both experts again stress the severe allergic reactions are rare. They average about one reaction per one million doses. Each vaccine site has protocols in place to help if a reaction happens.