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COVID-19 vaccine guide: What to know if you have allergies, cancer, autoimmune disease

Some people may have to wait or proceed with caution.
Certain patients must consider the risk-benefit ratio and discuss it with their doctor.
Certain patients must consider the risk-benefit ratio and discuss it with their doctor.TODAY Illustration / Getty Images
/ Source: TODAY

People dealing with cancer, severe allergies and other health conditions may have extra questions about getting the COVID-19 vaccine even as it promises to end the coronavirus epidemic.

Health care workers and nursing home residents are already receiving the Pfizer shot, while Moderna’s version is expected to get authorization for emergency use soon.

The data from the clinical trials “looks terrific,” said Dr. Larry Corey, an expert in virology, immunology and vaccine development, and professor in the vaccine and infectious disease division at the Fred Hutchinson Cancer Research Center in Seattle.

The Pfizer-BioNTech vaccine was 95% effective at preventing symptomatic COVID-19 after the second dose, with Moderna announcing similar results for its candidate.

“At the moment, we're looking that everybody in the country warrants vaccination,” Corey told TODAY.

“In the end, the entire adult population, and… once the dose and the safety is established in kids — the entire kid population.”

People at highest risk are first in line, with the general population getting access to the shot in the coming months. It’s meant for people with underlying medical conditions, including diabetes and heart disease, that could lead to the severe form of COVID-19.

Right now, it’s hard to know who should not get the vaccine, Corey noted. Certain patients must consider the risk-benefit ratio and discuss it with their doctor. Some may have to wait or proceed with caution.

Here’s what to keep in mind:

People with allergies

A health care worker in Alaska was among several people who’ve had a severe allergic reaction to the Pfizer vaccine.

Anyone experiencing such a reaction to any component of the shot should not be vaccinated, the Centers for Disease Control and Prevention warned.

Dr. Anthony Fauci also recently said people who’ve had Guillain-Barre syndrome, a rare neurological reaction to either influenza or the flu vaccine, should not get the COVID-19 vaccine “because you might trigger a similar, serious response." That’s a very small number of people, Fauci added.

GBS is an autoimmune disorder in which a person’s immune system damages the nerves, causing muscle weakness and sometimes paralysis. The exact cause is not known, but researchers have studied vaccines as a possible trigger in rare cases.

Fauci’s recommendation was made out of an abundance of caution, Corey noted.

People who have had a history of severe allergic reactions to any other vaccine or injectable medicine can still get the COVID-19 vaccine, but should be counseled about the risks and weigh them with the benefits, the CDC advised. If they decide to proceed with the shot, they should be observed for 30 minutes afterwards.

“If you have allergies, you want to get vaccinated in a place that knows how to take care of someone who has an allergic reaction,” Corey said.

Those with mild allergic reactions to any other vaccine or who have food, pet, venom or latex allergies have the green light to get the COVID-19 vaccine, but should be watched for 15 minutes afterwards, the CDC said.

Since the Pfizer-BioNTech and Moderna vaccines are similar, the precautions will likely be the same for both, Corey noted.

People with weakened immune systems

Immunocompromised persons, including cancer patients undergoing chemotherapy and people with HIV, may still receive the COVID-19 vaccine but should be counseled that doctors don’t yet know how safe or effective the shot is for them, the CDC advised.

They may have a reduced immune response and should continue to take measures including wearing masks and social distancing.

The National Cancer Institute is starting to do studies in this group, Corey noted, advising these patients to wait or proceed with caution. "Whether they will qualify or anybody would give them the vaccine is another issue,” he added.

People with autoimmune diseases

Again, the risks and benefits should be considered. One of Corey’s older relatives has lupus, an autoimmune disease, and he’s still recommending vaccination.

“The risk of COVID, because of its circulation and its attack rate, is very high, so I think that's worth the risk-benefit ratio, but recognize that we all have to make those kind of informed choices,” he said.

Pregnant and breastfeeding women

The COVID-19 vaccine has not been tested in pregnant women but studies in this population are planned, according to the American College of Obstetricians and Gynecologists.

Experts believe messenger RNA vaccines — like the Pfizer-BioNTech and Moderna shots — are unlikely to pose a risk for pregnant women, so they may choose to be vaccinated, the CDC noted.

Pregnant women “should be free to make their own decision in conjunction with their clinical care team,” ACOG agreed.

Both agencies had the same advice for women who are breastfeeding.

“That is an individual choice,” Corey said. “Women should discuss it with their physicians.”


Fewer children get sick with COVID-19 than adults, but they can spread the virus to others.

The Pfizer-BioNTech vaccine is authorized for people 16 and older. Healthy teens in this range wouldn’t qualify to get the shot for a while since it’s being prioritized for the most vulnerable populations, Corey said.

Pfizer has received approval from the Food and Drug Administration to test its vaccine on children as young as 12 and Moderna is planning to do a study of its vaccine in kids 12-17 years old.

The results for adolescents may be in by spring. Younger children need their own testing, with the results potentially coming later next year.