Can Antihistamines Help Stop Allergic Reactions to mRNA COVID-19 Vaccines?

• Many people experience a range of side effects from COVID-19 vaccines, including soreness at the injection site, fatigue, or headache, that resolve on their own within a day or two.
• There is a small risk of experiencing a serious allergic reaction to certain ingredients in the vaccine.
• If you had an allergic reaction to your first vaccine dose, your allergist may recommend taking a basic antihistamine before your second dose.

New research has found that antihistamines may help resolve the allergic reactions some people experience after receiving the Pfizer and Moderna messenger RNA (mRNA) vaccinations against COVID-19.

The paper, published in JAMA Internal Medicine on Monday, evaluated the safety of second doses in people who experienced an allergic reaction after the first dose. Researchers found that people’s symptoms were minimized or resolved with antihistamine treatment.

Many people experience a range of side effects from COVID-19 vaccines, including soreness at the injection site, fatigue, or headache, that resolve on their own within a day or two.

There is a small risk of experiencing a serious allergic reaction to certain ingredients in the vaccine — polyethylene glycol or polysorbate — but according to the findings, most reported reactions to the vaccines did not cause anaphylaxis.

If you experienced a reaction after your first dose, “your allergist may recommend premedicating with an antihistamine to dampen the body’s response to the histamine released in the body as a response to the vaccine, therefore lessening the severity of symptoms,” said Dr. Sanjeev Jain, a board certified allergist and immunologist at Columbia Allergy on the West Coast.