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Who Should Avoid a Covid-19 Vaccine: Severe Allergies Explained

Dec. 22, 2020, 10:30 AM

Severe allergic reactions to Pfizer Inc.'s Covid-19 vaccine in a handful of cases have prompted questions over whether certain people should avoid getting inoculated.

The Centers for Disease Control and Prevention has identified six cases of anaphylaxis out of more than 270,000 doses of Pfizer-BioNTech’s vaccine administered as of Dec. 18. Moderna’s vaccine, whose rollout begins this week, contains similar components as Pfizer’s.

But unless someone is allergic to an ingredient in the vaccine, the CDC recommends that they should still get the shot. Anyone with a history of bad reactions to other vaccines or injectible medicines should take certain precautions.

1. Who shouldn’t get the shot?

Anyone who’s experienced a severe allergic reaction either to an ingredient in the vaccine, or after they’ve gotten their first dose. There are no other conditions under which someone shouldn’t take the vaccine, according to U.S. health guidelines.

The FDA concluded any serious adverse events observed during the clinical trial didn’t raise safety concerns and weren’t necessarily linked to the vaccination.

Common side effects include pain or swelling at the injection site, along with fever, tiredness, headache, and chills. Most of those should subside in a few days. Such side effects are normal and are actually a sign that the vaccine is doing what it’s supposed to do.

2. What about shellfish or egg allergies?

Probably not a concern. But people with those allergies may require extra monitoring, depending on the severity of their past reactions.

Anyone who has a history of serious allergic reactions, such as anaphylaxis, should be monitored for 30 minutes after inoculation. Everyone else should be monitored for 15 minutes, under CDC guidance.

However, U.K. regulators recommend that “anyone with a history of anaphylaxis to a food/vaccine/medicine should NOT be given the Pfizer/BioNTech vaccine.”

3. What about unknown allergies?

People should inform their vaccine provider of any and all medical conditions. Any specific questions should be directed to their doctor.

The ingredient list for both vaccines is fairly short, mostly compromised of a messenger RNA platform, a fatty layer of lipids to coat it, sodium, and potassium. Neither vaccine contains any part of the actual virus, nor do they have any preservatives.

Vaccine administration sites must carry treatments to manage allergic reactions, including ways to treat severe, life-threatening allergy. But that requirement is true of any new vaccine and isn’t unique to Covid-19.

4. What is the FDA doing to monitor side effects?

The FDA and CDC track all vaccines for side effects long after they come onto the market. But the U.S. government is taking extra steps for Covid-19 vaccines, including using a smartphone tool called V-Safe. V-Safe uses text messaging and web surveys to check in with people who’ve gotten vaccinated and monitor any reactions.

Vaccine providers must report to the federal agencies any administration errors and serious adverse events—even if they’re not related to the vaccination itself. They also must report cases of Multisystem Inflammatory Syndrome, which has been linked to children who get Covid-19, along with cases of the virus that result in hospitalization or death.

To Learn More:

—From Bloomberg Law:
Fauci Seeks Scientific Sprint to Create Universal Virus Vaccine

Fauci Curious to See Secret of Covid Shot’s Success Unlocked

Why Covid-19 Vaccines Can’t Be Silver Bullet: Immunity Explained

Single Pfizer Shot Staves Off Covid, but for How Long Unknown

—From Bloomberg News:
NIH to Study Allergic Reactions Linked to Covid-19 Shots

CDC Advisory Panel Votes to Recommend Moderna’s Covid-19 Vaccine

Moderna Shot Cleared in U.S., Ready for Delivery Starting Sunday

Vaccine Rollout Hits First U.S. Snags With Delays, Allergic Case

Side Effects of Pfizer’s Covid Shot Focus as FDA Advisers Meet

To contact the reporter on this story: Jeannie Baumann in Washington at

To contact the editors responsible for this story: Fawn Johnson at; Alexis Kramer at; Jo-el J. Meyer at