“If I were a person that had an underlying allergic tendency, I might want to be prepared that I might get a reaction, and therefore be ready to treat it,” Dr. Fauci said, in a webcast moderated by Dr. Sanjay Gupta of CNN, sponsored by Harvard and The New England Journal of Medicine.
Dr. Fauci acknowledged that the problem could turn out to affect a lot of people.
“That’s one of the reasons why it’s important to cover the waterfront with different vaccine platforms,” he said, adding, “If in fact we do find out that there is a consistent issue of a certain subset of people like those with allergic reactions, you’ll always have other vaccine platforms that you can use and hopefully you will not see that with those other platforms.”
Should people with allergies avoid Pfizer’s vaccine?
Dr. Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia, said the initial, broad recommendation in Britain mentioning severe allergic reactions seemed to be an overreaction that could needlessly scare many people away from a desperately needed vaccine in the middle of a raging pandemic.
Millions of people in the United States are allergic to foods like eggs or peanuts, as well as medicines or bee stings, and have had reactions that were serious enough to lead doctors to advise them to carry epinephrine injectors. But that does not necessarily mean the vaccine is risky for them, he said. About five percent of children and four percent of adults in the United States have food allergies, according to the National Institute of Allergy and Infectious Diseases.
Fewer than one in a million recipients of other vaccines a year in the United States have an anaphylactic reaction, Dr. Offit said.
The Road to a Coronavirus Vaccine ›
Answers to Your Vaccine Questions
As the coronavirus vaccine get closer to U.S. authorization, here are some questions you may be wondering about:
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- If I live in the U.S., when can I get the vaccine? While the exact order of vaccine recipients may vary by state, most will likely put medical workers and residents of long-term care facilities first. If you want to understand how this decision is getting made, this article will help.
- When can I return to normal life after being vaccinated? Life will return to normal only when society as a whole gains enough protection against the coronavirus. Once countries authorize a vaccine, they’ll only be able to vaccinate a few percent of their citizens at most in the first couple months. The unvaccinated majority will still remain vulnerable to getting infected. A growing number of coronavirus vaccines are showing robust protection against becoming sick. But it’s also possible for people to spread the virus without even knowing they’re infected because they experience only mild symptoms or none at all. Scientists don’t yet know if the vaccines also block the transmission of the coronavirus. So for the time being, even vaccinated people will need to wear masks, avoid indoor crowds, and so on. Once enough people get vaccinated, it will become very difficult for the coronavirus to find vulnerable people to infect. Depending on how quickly we as a society achieve that goal, life might start approaching something like normal by the fall 2021.
- If I’ve been vaccinated, do I still need to wear a mask? Yes, but not forever. The two vaccines that will potentially get authorized this month clearly protect people from getting sick with Covid-19. But the clinical trials that delivered these results were not designed to determine whether vaccinated people could still spread the coronavirus without developing symptoms. That remains a possibility. We know that people who are naturally infected by the coronavirus can spread it while they’re not experiencing any cough or other symptoms. Researchers will be intensely studying this question as the vaccines roll out. In the meantime, even vaccinated people will need to think of themselves as possible spreaders.
- Will it hurt? What are the side effects? The Pfizer and BioNTech vaccine is delivered as a shot in the arm, like other typical vaccines. The injection won’t be any different from ones you’ve gotten before. Tens of thousands of people have already received the vaccines, and none of them have reported any serious health problems. But some of them have felt short-lived discomfort, including aches and flu-like symptoms that typically last a day. It’s possible that people may need to plan to take a day off work or school after the second shot. While these experiences aren’t pleasant, they are a good sign: they are the result of your own immune system encountering the vaccine and mounting a potent response that will provide long-lasting immunity.
- Will mRNA vaccines change my genes? No. The vaccines from Moderna and Pfizer use a genetic molecule to prime the immune system. That molecule, known as mRNA, is eventually destroyed by the body. The mRNA is packaged in an oily bubble that can fuse to a cell, allowing the molecule to slip in. The cell uses the mRNA to make proteins from the coronavirus, which can stimulate the immune system. At any moment, each of our cells may contain hundreds of thousands of mRNA molecules, which they produce in order to make proteins of their own. Once those proteins are made, our cells then shred the mRNA with special enzymes. The mRNA molecules our cells make can only survive a matter of minutes. The mRNA in vaccines is engineered to withstand the cell’s enzymes a bit longer, so that the cells can make extra virus proteins and prompt a stronger immune response. But the mRNA can only last for a few days at most before they are destroyed.
Those reactions are treatable, and much easier to control than a severe case of Covid-19, he said.
Many people with allergies to foods, bee stings or medicines have received multiple vaccines without problems.
As a member of the F.D.A. advisory panel that met on Thursday, Dr. Offit voted in favor of authorizing the Pfizer vaccine. But during the panel’s discussion of allergic reactions, he said, “this issue is not going to die until we have better data.”
