Health officials are monitoring safety while COVID-19 vaccines are rolled out

As COVID-19 vaccinations become available to more and more people, health authorities are keeping a close watch for unexpected side effects.

On Tuesday, a health worker in Alaska developed a severe allergic reaction after receiving the Pfizer COVID-19 vaccine. She is under observation in the hospital for another night, while another employee, who was vaccinated on Wednesday, has recovered. Doctors already knew to be wary after Britain reported two similar cases last week.

In the US, vaccine recipients are believed to hang around after the injection in case signs of an allergy appear and they need immediate treatment – exactly what happened when the health worker in Juneau turned red and became short of breath 10 minutes after the injection. The second worker experienced puffiness in the eyes, light-headedness and a scratchy throat.

Allergies are always a question of a new medical product, but checking COVID-19 vaccines for other, unexpected side effects is more challenging than usual. It’s not just because so many people will need to be vaccinated in the coming year. Never before have so many vaccines made in different ways been converged at the same time – and it’s possible that one shot option has different side effects than another.

The first vaccine to be widely used in the US and many Western countries, made by Pfizer Inc. and Germany’s BioNTech, and a second option coming soon from competitor Moderna Inc. is expected, both are created in the same way. The Food and Drug Administration says massive studies of each haven’t uncovered major safety concerns.

But allergy concerns “reiterate the importance of real-time safety monitoring,” said Dr. Jesse Goodman of Georgetown University, a former FDA vaccine leader.

And the authorities have multiple ways to keep track of how people are doing, as these COVID-19 vaccines, and hopefully more in the coming months, hit more arms.


Getting the Pfizer-BioNTech Injection or the Moderna version can cause temporary discomfort, as can many vaccines.

In addition to a sore arm, people may experience fever and flu-like symptoms – fatigue, aches, chills, headaches. They last about a day, sometimes bad enough that recipients miss work, and are more common after the second dose and in younger people.

These reactions are a sign that the immune system is on the rise. COVID-19 vaccines tend to cause more of those reactions than a flu shot, about what people experience with shingles vaccinations. But some resemble early symptoms of the coronavirus, one reason hospitals are shaky when their employees are vaccinated.


The FDA found no serious side effects among the tens of thousands who took part in studies of the two vaccines.

Yet problems so rare that they do not appear in even very large studies sometimes occur when a vaccine is more widely used and without the strict rules of a clinical trial.

The first allergy notifications from England involved people with a history of severe allergies, and the UK authorities warned people with severe previous experience to delay vaccination as they determine which ingredient could be a problem.

US health authorities give more nuanced advice. People are always asked about allergies before any vaccinations are given, and instructions for the Pfizer-BioNTech injection say avoid it if you are severely allergic to any of the ingredients or have had a severe reaction to a previous dose. Health professionals can peruse the ingredient list.

The Centers for Disease Control and Prevention advises people to stay for 15 minutes after vaccination and those with a history of other allergies for 30 minutes so they can be treated immediately if they have a reaction.

The Alaska health worker, who doctors say had no history of allergies, followed that advice and was promptly cared for a particularly serious reaction called anaphylaxis. She recovered after a night of observation in the hospital, but was not given a second dose of vaccine.

Doctors in Alaska have warned US authorities, who will continue the required monitoring to tell how common these types of reactions really are. This will be especially important as there is enough vaccine coming in for injections to be administered outside of health care facilities that have a lot of experience in dealing with these types of reactions.

Balancing potential risks with the benefits of the vaccine in the pandemic is an ongoing process, warned Dr. Jay Butler of the CDC Wednesday.


The challenge is determining whether the vaccine caused a health problem or whether it was a coincidence. Don’t be too quick to conclude that there is a connection, health authorities stress.

The way to tell: comparing all reports of possible side effects with data showing how often the same condition occurs routinely in the population.

The government has several ways to do that. Physicians are required to report any problems patients have. But the FDA is investigating huge databases of insurance claims for early warning signs that health problems are more common in newly vaccinated people than everyone else.

On the list to check is Bell’s palsy, a temporary facial paralysis that occurred in a handful of people in both vaccine studies. The FDA said it’s likely a coincidence, but will definitely follow.

Vaccine recipients can help with additional safety monitoring. The program, called “v-safe”, automatically sends a daily text asking how people are feeling the first week after each vaccine dose, and then a weekly text for the next five weeks. Any responses that indicate a concern ask for a phone call for more information.


The Associated Press Department of Health and Science is supported by the Howard Hughes Medical Institute’s Science Education Department. The AP is solely responsible for all content.