The Strange New COVID Vaccine Side Effect That's Confusing Even Doctors

This odd side effect hits you right away and can last for several days, experts say.

The three COVID vaccines approved in the U.S.—from Pfizer, Moderna, and Johnson & Johnson—can come with quite a few side effects, which doctors say just mean that your body is having a strong immune response. Of course, that doesn't make them any less uncomfortable. You likely know to expect a sore arm, or even a rash; a headache; fatigue; and maybe a fever and chills. But recently, some people have been reporting a strange new side effect from the vaccine that is confusing even doctors. To find out more about this rare side effect that could crop up in your mouth, read on, and to see which side effect is good news, check out This One Side Effect Signals a "Very Robust" Vaccine Response, Doctor Says.

People have reported experiencing a metallic taste in their mouth as a side effect of the vaccine.

Young woman is looking on her tongue in the mirror

Recently, people have reported experiencing an intense metallic taste in their mouth after getting the COVID vaccine. The taste is "like having nickels in your mouth," a South Carolina patient named John Howard told NBC News. "It's certainly not debilitating or anything like that, but I do hope it goes away. I would like my coffee to taste normal."

Howard is not the only one to report such an experience—doctors have confirmed they are seeing it crop up too. Infectious disease expert and the director of the Vanderbilt Vaccine Research Program at the Vanderbilt University, Buddy Creech, MD, told NBC News he's seen a few individuals report the unpleasant taste following their COVID vaccination. And Tania Mucci-Elliott, MD, clinical instructor of infectious disease and internal medicine at NYU Langone, said she's seen a handful of cases of metallic taste post-vaccine, but, she told Popsugar, "it seems to be rare."

Doctors aren't 100 percent sure what causes it.

older white man looking at the camera and sticking his tongue out

"Metallic taste is interesting because we really don't know the biological basis for it," Nancy Rawson, PhD, vice president of the Monell Chemical Senses Center in Philadelphia, told NBC News. "There is no metallic taste receptor."

John A. Sellick, Jr., DO, professor of medicine in the Division of Infectious Diseases at University at Buffalo-SUNY, ventured a guess, however. "I suspect it's part of a 'vagal' response—the same one that gives you sweats, flushing, and lightheadedness in anticipation of an injection [or] procedure," he told Popsugar.

To see which side effect you're more likely to have from the Pfizer shot, check out The One Side Effect That's Much More Common With Pfizer, Data Shows.

This side effect has come up with other treatments and vaccines.

Teenager boy being vaccinated

Although rare, developing a metallic taste as a side effect from a treatment is not completely unheard of, according to NBC News. They report that it's come up with other vaccines, antibiotics, and pain medications.

While it may seem strange, Creech notes the metallic taste is not a side effect to be concerned about. It does not "indicate anything that would prevent getting the second dose of vaccine," he said.

But if you're worried, Mucci-Elliott told Popsguar that "there's no harm in reaching out to your doctor and letting them know."

To see if you're more susceptible to an intense vaccine response, check out This Is Why Half of People Have Stronger Vaccine Side Effects, CDC Says.

The taste comes within minutes of getting the vaccine.

A young female nurse gives a middle-aged man a COVID vaccine in his arm.

According to NBC News and Popsugar, those who experienced the metallic taste following vaccination said it came on within minutes of their first dose. Unlike other COVID vaccine side effects that sometimes take hours to appear, it seems that if you don't experience the taste rather immediately, it's unlikely to show up at all.

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The side effect can last up to several days.

Man not eating upset because he lost his sense of taste

One man who talked with NBC News, Paul Wartenberg of Florida, said the metallic taste persisted for several hours after his vaccination but finally dissipated after he ate dinner. Howard said he tried to get rid of the taste with coffee, then mouthwash, but it didn't go away for days. Dave Bischel of California told NBC News that the taste stayed with him for a few days as well. Creech and Mucci-Elliott also said the patients they've seen mostly dealt with the metallic taste for several days.

But Sellick noted that if you experience this symptom a few days after your COVID vaccine, it may be due to a COVID infection as opposed to a side effect. "If it happens days later, especially if in combination with loss of smell, it's a fairly solid sign of SARS-CoV-2 infection," he told Popsugar.

But if you are in fact dealing with a metallic taste in your mouth as a COVID vaccine side effect, Rawson suggests drinking a lot of water to help your saliva return to its "optimal composition to clear things out of your mouth."

And if you don't have a strong reaction to your shot, check out This Is What It Means If You Have No Vaccine Side Effects, Doctors Say.

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