As measles infections become the new normal in America, with outbreaks occuring around the United States and cases reported in 44 states in 2025, you may be wondering: Can I get measles if I’m vaccinated?
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“You can still get measles if vaccinated, but it’s very rare,” says Walter Orenstein, MD, associate director of the Emory Vaccine Center in Atlanta.
Still, some people who are vaccinated may need a booster shot. Here’s what to know.
How Effective Is the Measles Vaccine?
The full two-dose MMR vaccine (a combo shot that protects against measles, mumps, and rubella) is 97 percent effective at preventing measles, typically for life. A single vaccine dose is about 93 percent effective.
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In 2025, 93 percent of reported U.S. measles infections were among people who were unvaccinated or of unknown vaccination status.
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A person who contracts measles despite being vaccinated usually experiences milder illness and is less contagious.
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Dr. Orenstein adds that MMR shots are very safe, and most people experience no side effects. Those that do report minor symptoms, including soreness at the injection site, slight fever, or rash.
What if You’re Unsure of Your Vaccination Status?
If you’re uncertain whether or not you’ve received the measles shot and can’t find your medical records, check to see if your city or state has a centralized registry of vaccine records.
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If that doesn’t yield the information you need, check with your current healthcare provider and possibly prior providers.
If you’re uncertain of your status and think you may be in a situation where you are exposed to measles, there’s no harm in getting an extra vaccine dose, Orenstein says.
Does Anyone Need a Measles Booster?
For most people who have received two doses of the MMR vaccine, there is no need for a measles booster shot, says Deborah Fuller, PhD, a professor of microbiology and a vaccine researcher at the University of Washington School of Medicine in Seattle.
But there are some groups who could benefit. Dr. Fuller says you should talk to your healthcare provider about a booster if:
- You’ve only had one measles shot. A second dose is particularly important for healthcare workers, college students, some people with HIV, and people close to anyone with a compromised immune system. (Immunocompromised people themselves may not be eligible for vaccination.)
- You were vaccinated between 1968 and 1989. “There may be some gap in immunity, as during that time only one dose was recommended,” says Catherine Troisi, PhD, a professor of management policy and community health at the UTHealth Houston School of Public Health.
- You were vaccinated between 1963 and 1967. During these years, some vaccines used an inactive virus, which was not as effective as the current vaccine, which is a live, attenuated (weakened) type. Dr. Troisi says that, to be safe, adults in this group should get at least one booster with the current vaccine.
Why Measles Vaccination Matters
Measles is highly contagious. Among the unvaccinated, 9 out of 10 will come down with measles if they are exposed to an infected person.
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The virus can also linger even after an infected person has left the room, says Peter Chin-Hong, MD, an infectious disease specialist and professor of medicine at the University of California San Francisco School of Medicine. “It can persist as airborne tiny droplets for two hours in an enclosed space,” he says.
Dr. Chin-Hong says measles can lead to some very serious health issues, including pneumonia (a severe lung infection) and encephalitis (inflammation of the brain), which can cause disability and long-term complications.
Even a mild case of measles can lead to lingering damage to the immune system known as immune amnesia, making a person more vulnerable to other diseases ranging from flu to tuberculosis.
“It is measles’ impact of causing long-lasting immunosuppression that gives me the most pause, and is perhaps the most invisible and not easily captured in metrics,” Chin-Hong says. Having a weakened immune system raises the risk of other infections and even death, “months to years after the original measles diagnosis.”
Declining Vaccination Is Driving Measles Outbreaks
Measles broke U.S. records in 2025, with 2,225 confirmed cases nationwide — the highest number in over three decades.
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The situation could improve if more Americans would get the measles vaccine. “When almost everyone gets vaccinated, you can eliminate measles transmission in a country, and that’s a big deal,” says Adam Ratner, MD, a pediatric infectious disease specialist and vice chairperson of the committee on infectious diseases at the American Academy of Pediatrics.
Experts largely attribute the ongoing surge in measles to a steady decline in the number of children getting vaccinated.
The latest data show that kindergarten MMR vaccination coverage fell to about 92.5 percent for the 2024-2025 school year — down from 95 percent in 2019-2020.
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At least 95 percent coverage is needed to prevent outbreaks, scientists say.
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“We’ve had confusing messaging from the federal government and changes to the vaccine schedule that are not based on science, and I think that that has confused parents and made people more likely to opt out of vaccination,” says Dr. Ratner.
