MMR Booster for Adults: Is It Necessary?
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Is an MMR Booster for Adults Necessary?

As measles cases continue to surge, you may be wondering if you’re sufficiently protected or if you could benefit from an MMR vaccine booster.
Is an MMR Booster for Adults Necessary?
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With the current measles outbreak showing no sign of letting up, you may be wondering: If I’m fully vaccinated, am I at risk?

The short answer is no. If you’ve received the measles, mumps, and rubella (MMR) vaccine, you’re likely protected for life.

 “Most people who have received two doses of the MMR vaccine do not need a measles booster shot, but some specific individuals may benefit,” says Deborah Fuller, PhD, a professor of microbiology and a vaccine researcher at the University of Washington School of Medicine in Seattle. Also, if you’ve had measles, current scientific evidence suggests you can’t get it again.

Still, Fuller says it’s vital to know your vaccination and health history, and whether you may benefit from an MMR vaccine booster if you’re in a vulnerable group.

U.S. Measles Outbreak: What’s the Latest?

Because measles is one of the most transmissible of all known infections, concerns are running high now as an outbreak in the United States continues to grow.

In Texas, which has been the epicenter of the current measles outbreak, the case count has risen by at least 22 since February 25 to a total of 146, according to the most recent data available. Twenty of those patients have been hospitalized, and one “school-aged child” who was not vaccinated has died of the illness.

 The casualty is the first measles death in the United States in a decade.

Of those people infected, 116 have been children younger than 17 — the majority of those (79) were unvaccinated, while 62 have unknown vaccination status.

In the latest update from the Centers for Disease Control and Prevention (CDC), the case total nationwide has hit at least 164, with infections now reported in Alaska, California, Georgia, Kentucky, New Jersey, New Mexico, New York City, Rhode Island, and Washington.

Who Should Consider an MMR Booster?

Public health authorities recommend consulting with your healthcare provider to check if you might be among those who could benefit from a booster or revaccination. Those who might consider a booster include:

  • People Who Have Had Just One Measles Shot A single dose of the MMR vaccine is around 93 percent effective at preventing measles, whereas two doses are considered fully protective at about 97 percent effectiveness.

    Public health officials specifically underscore that healthcare workers, college students, some people with HIV, and family members and close contacts of people with compromised immune systems also receive a second dose if they have received only one dose.

  • People 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. Still, adults born during or after 1957 who received at least one dose of live measles virus-containing vaccine (MMR) on or after their first birthday should be protected against measles in most cases. (Note: People born before 1957 are likely to have been infected and are presumed to be protected against measles, mumps, and rubella.)

  • People Vaccinated Between 1963 and 1967 Adults may have been vaccinated during these years with either inactivated (killed) measles vaccine or measles vaccine of unknown type. They should be revaccinated with at least one dose of live, attenuated measles vaccine (MMR). A killed measles vaccine available during this time and given to a small percentage of the population was not as effective.

  • People Who Are Unsure of Their Vaccination Status Saahir Khan, MD, PhD, an infectious disease specialist with Keck Medicine of USC in Los Angeles, advises getting a two-dose series of MMR vaccine if you are unsure of your vaccine status. “There is no increased risk from additional doses,” says Dr. Khan.
The CDC cautions that some people should not receive the vaccine, including people who have had a severe allergic reaction to a previous dose or a vaccine component, individuals who have severe immunodeficiency (HIV patients and certain cancer patients), those who are pregnant, and most babies under 6 months of age.

Why Is the MMR Vaccine Important for Preventing Measles?

This week the secretary of the U.S. Department of Health and Human Services (HHS), Robert F. Kennedy Jr., issued a “call to action,” noting the importance of the MMR vaccine in protecting children and those who cannot get vaccinated, as well as for promoting immunity in communities. Kennedy has historically questioned the safety of some vaccines, including the MMR vaccine.

“As healthcare providers, community leaders, and policymakers, we have a shared responsibility to protect public health,” Kennedy wrote in a FoxNews.com op-ed that was also posted to the HHS site. “This includes ensuring that accurate information about vaccine safety and efficacy is disseminated. We must engage with communities to understand their concerns, provide culturally competent education, and make vaccines readily accessible for all those who want them.”

Vaccination has been highly effective at stopping measles spread, and thanks to a widely followed immunization program, the United States declared the disease officially eliminated 25 years ago. Elimination means the virus had not been actively spreading in the United States, and cases were identified only in people who got the disease abroad and returned to the country.

Of the cases identified so far this year, 95 percent have been among those who were unvaccinated or with unknown vaccination status.

“An unimmunized person exposed to measles has a 90 percent chance of getting sick, but an immunized person after two doses of MMR vaccine has a 97 percent chance of being protected,” says Patsy Stinchfield, NP, the immediate past president of the National Foundation for Infectious Diseases.

In its first statement regarding the outbreak, the CDC stressed that measles does not have a specific antiviral treatment, and vaccination remains the best defense against infection.

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Measles Outbreaks in the U.S. Highlight the Importance of Vaccination. Johns Hopkins Bloomberg School of Public Health. February 26, 2025.
  2. Measles, Mumps, and Rubella (MMR) Vaccination: What Everyone Should Know. Centers for Disease Control and Prevention. January 26, 2021.
  3. Measles Frequently Asked Questions. NYC Health.
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  5. Measles Outbreak. Texas Health and Human Services. February 28, 2025.
  6. Smith J. Daily briefing: An unvaccinated child is first US measles death in a decade. Nature. February 27, 2025.
  7. Measles Cases and Outbreaks. Centers for Disease Control and Prevention. February 28, 2025.
  8. First Measles Case of 2025 in Washington State Identified in a King County Infant. King County. February 27, 2025.
  9. Routine Measles, Mumps, and Rubella Vaccination. Centers for Disease Control and Prevention. January 26, 2021.
  10. History of Measles. Centers for Disease Control and Prevention. May 9, 2024.
  11. Measles Vaccination Recommendations. Colorado Department of Health & Environment.
  12. Yang Y. The Perils of RFK Junior's Anti-Vaccine Leadership for Public Health. The Lancet. January 11, 2025.
  13. Measles Outbreaks Reported in Nine States. Trust for America’s Health. March 3, 2025.
  14. National Update on Measles Cases and Outbreaks — United States, January 1–October 1, 2019. Centers for Disease Control and Prevention. October 11, 2019.
  15. CDC Statement on Measles Outbreak. Centers for Disease Control and Prevention. February 27, 2025.

Emily Kay Votruba

Fact-Checker
Emily Kay Votruba has copyedited and fact-checked for national magazines, websites, and books since 1997, including Self, GQ, Gourmet, Golf Magazine, Outside, Cornell University Press, Penguin Random House, and Harper's Magazine. Her projects have included cookbooks (Padma Lakshmi's Tangy Tart Hot & Sweet), self-help and advice titles (Mika Brzezinski's Know Your Value: Women, Money, and Getting What You're Worth), memoirs (Larry King's My Remarkable Journey), and science (Now You See It: How the Brain Science of Attention Will Transform How We Live, Work, and Learn, by Cathy Davidson). She started freelancing for Everyday Health in 2016.

Don Rauf

Author

Don Rauf has been a freelance health writer for over 12 years and his writing has been featured in HealthDay, CBS News, WebMD, U.S. News & World Report, Mental Floss, United Press International (UPI), Health, and MedicineNet. He was previously a reporter for DailyRx.com where he covered stories related to cardiology, diabetes, lung cancer, prostate cancer, erectile dysfunction, menopause, and allergies. He has interviewed doctors and pharmaceutical representatives in the U.S. and abroad.

He is a prolific writer and has written more than 50 books, including Lost America: Vanished Civilizations, Abandoned Towns, and Roadside Attractions. Rauf lives in Seattle, Washington.