close up of a COVID-19 spike

Benefits outweigh risks of COVID-19 vaccines

Texans are lining up to receive their COVID-19 vaccine and many more are patiently waiting their turn. The good news is that while COVID-19 can be life-threatening, the only medical risk to vaccination is for those with a history of allergic reactions to these vaccines or their ingredients.

The vaccines produced by Pfizer and Moderna are messenger RNA (mRNA) vaccines. They have good safety profiles dating back eight months to when the vaccines were first given to clinical trial volunteers. At the time of the Emergency Use Authorization, more than 30,000 people had received one or the other vaccine through a clinical trial. Both vaccines demonstrated side effects similar to other routinely given vaccines. Now, even more is known because well over 2 million doses have been given since the authorizations.

Several cases of anaphylaxis came to light once vaccination of the public began. Anaphylaxis is a potentially life-threatening allergic reaction caused by things like foods, medications and insect stings. It also occurs rarely with vaccination.

The rate of anaphylaxis with the COVID-19 vaccines is 11 persons per one million vaccinated. To put this in perspective, anaphylaxis is treatable, but COVID-19 has contributed to about 380,000 American lives. Even COVID-19 survivors may suffer disabling long-term aftereffects from the virus. Anaphylaxis, when it occurs, typically appears 13 minutes after COVID-19 vaccination.

This is the reason for the 15-minute observation period following vaccination. People with lip-swelling, hives or difficulty breathing within four hours after receiving their first COVID-19 mRNA vaccine shouldn’t receive a second dose.

Both vaccines are preservative-free and contain sugar, salts and fats. Neither vaccine contains egg, gelatin, latex or preservatives. The main fat, polyethylene glycol, can cause a vaccine reaction if someone is allergic to it. People who’ve prepared for colonoscopy have likely drank a similar formulation of polyethylene glycol.

Polysorbate is related to polyethylene glycol and also is found in the vaccines. People allergic to either polyethylene glycol or polysorbate should avoid the mRNA COVID-19 vaccines but shouldn’t despair. Other non-mRNA COVID-19 vaccines are likely to receive authorization in the next few months.

What about other allergies? Severe environmental, pet or food allergies aren’t a reason to avoid the mRNA vaccines. It also may be OK to receive these vaccines if there’s a history of severe allergic reactions to other vaccines. Those with a history of severe vaccine allergies should discuss receiving a COVID-19 vaccine with an allergist.

Just as with other vaccines, the COVID-19 vaccines have relatively minor side effects such as a sore arm, fatigue, headache and low-grade fever. Side effects are reassuring as they’re evidence the immune system is doing its job. Most all side effects go away within three days. Acetaminophen or ibuprofen can help with symptoms.

Health care workers are lined up to receive their COVID-19 vaccine. Most were motivated by first-hand knowledge of the destruction caused by the virus. Unless you’re allergic to the COVID-19 vaccines or their ingredients, you should take your first opportunity to get vaccinated.

Vaccine Smarts is written by Sealy Institute for Vaccine Sciences faculty members Drs. Megan Berman, an associate professor of internal medicine, and Richard Rupp, a professor of pediatrics at the University of Texas Medical Branch. For questions about vaccines, email