Ask Dr. Hamblin: Is My Fear of Vaccine Allergies Overblown?

Despite alarming news reports, most allergies shouldn’t be an issue.

An illustration of someone getting a vaccine.
Julian Montague

Editor’s Note: Every Wednesday, James Hamblin takes questions from readers about health-related curiosities, concerns, and obsessions. Have one? Email him at

Dear Dr. Hamblin,

I had an anaphylactic reaction 25 years ago to a routine tetanus shot, and it was terrifying. After being shot full of adrenaline, I was told that that should be the last tetanus shot I ever got. Since then, I have never had any shots at all, since I am too scared.

Now I am reading that the National Health Service in the U.K. advised that people who have had such reactions to anything should not take the Pfizer vaccine. I had already wondered about getting the vaccine when it becomes available, but now I am even more disinclined to do so. Should I be?

Patricia S. Cole

Bluffton, South Carolina


The messaging about allergies and vaccination has the potential to be very misleading, so I feel your concern. But I’m extremely optimistic that you will be able to get vaccinated safely.

In the weeks since the rollout of the Pfizer/BioNTech vaccine to hundreds of thousands of people, eight serious reactions have so far been reported. The symptoms vary, and in some cases have required observation in the hospital. All of these people recovered, and none seem to have lasting issues.

Six of those cases happened in the United States, and the CDC has considered them cases of anaphylaxis—a severe allergic reaction that involves a full-body response, quickening the heart and narrowing the airways, not simply redness or itching or muscle pain. Reactions of the sort that have been reported always need to be taken seriously. As you’ve experienced, anaphylaxis requires immediate medical attention. When it happens, say, in response to a bee sting in the middle of the woods, anaphylaxis can be fatal. But in a medical setting, this sort of reaction is extremely manageable.

While these reports can sound scary—as can broad notes of caution that seem to implicate anyone with serious allergies to anything at all—they’re also a sign that the system is working. Around the world, roughly 2 million people have now received some form of the coronavirus vaccine. I’d be most concerned if that happened and we heard radio silence. Whenever millions of people get any medical treatment, or attempt to do anything, some will experience negative side effects or reactions. The real questions are just how unpleasant those effects will be, and how they compare with the disease we’re attempting to defeat. That comparison requires absolute transparency.

In these early days of COVID-19 vaccination, public-health agencies are under pressure to err on the side of recommending caution until more is known. This leads to advice similar to what you heard in the U.K.—that people with any sort of serious allergy should hold off on getting vaccinated. It’s sort of like evacuating a city block because a smoke alarm went off in one bathroom. Over time, the advice will get more precise as we come to understand exactly what triggered these reactions. Before the U.S. FDA advisory committee voted to authorize the Pfizer vaccine earlier this month, members noted that they needed to better understand any allergic potential before giving official guidance on whether people like you should wait to get vaccinated. (As of now, the FDA’s language is a stock warning about not vaccinating people with a “known history of severe allergic reaction to any component” of this vaccine.)

The FDA is currently convening a panel to scrutinize the reports of allergic reactions and attempt to understand their precise trigger. The prime suspect is the fatty nanoparticles that form an envelope around the fragments of viral genetic messaging code (mRNA) and help guide it to our cells. If we can identify what specific element of the vaccine may have triggered the allergic reactions so far, then other people who have similar allergies could be identified and monitored accordingly. Currently, the CDC recommends that anyone with a serious allergy of any sort should be monitored for 30 minutes after vaccination. If anaphylaxis is going to happen, it will be in that immediate period. So far, this approach seems to be effective.

Overall, the fact that these few cases are getting so much attention from regulators should be reassuring. No other new vaccine has been rolled out under such scrutiny, and scrutiny is the best safeguard. But the attention can also be a problem. Part of the reason these adverse reactions feel especially scary is the amount of press coverage that they get. When health officials in the U.K. reported that two people had anaphylactic reactions after getting vaccinated, it turned into a global news story. Then last week, The New York Times sent a push alert for a front-page story about a health-care worker in Alaska who had a serious allergic reaction and was under observation in a hospital. Stories like this, over time, make rare events seem more common than they are. They can stick in our head and skew our perception of risk, since we do not receive push alerts for each of the other 300,000 Americans who have been vaccinated uneventfully.

A sad fact about this pandemic is that most Americans have become numb to hearing that thousands of people die every day of COVID-19. Hundreds of thousands more are sickened, many of them seriously. Many have long-lasting symptoms. Now reports of negative reactions to vaccines are what’s new. But we can’t let novelty distract us from a sober risk assessment. Even if, in some hypothetical world, dozens of people had fatal reactions every day—again, this is not happening—that would pale in comparison with the damage the virus is doing.

A common fallacy when we are weighing options is thinking that high-risk inaction is better than low-risk action. Once vaccines are widely available, people will be asked to go out and do something that carries an apparently infinitesimal risk so that we can end a disease whose risk is far greater and is laid bare all around us daily. The pandemic does not end with the development of a vaccine. It ends only with herd immunity—when so many people are vaccinated that outbreaks, if they happen at all, are small and easily contained. The alternative to getting vaccinated isn’t “playing it safe.” The alternative to getting vaccinated is widespread death, endless masking, and distancing, and an indefinite pandemic.

In your specific case, with an illness such as tetanus, going without future doses of that vaccine might be a reasonable decision. The infection is very rare in most of the world. As long as you don’t work mending rusty fences or walk barefoot in scrap yards, you should be at low risk. That’s clearly not the case with the coronavirus. But with any vaccine-preventable disease, remember that the only reason a few people can pretty safely go without a shot is that so many other people didn’t.

“Ask Dr. Hamblin” is for informational purposes only, does not constitute medical advice, and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. By submitting a letter, you are agreeing to let The Atlantic use it—in part or in full—and we may edit it for length and/or clarity.