Doctors Explain Who May Need a Measles Booster

U.S. health officials report 2,777 confirmed measles cases across 47 states and territories as of Aug. 20, the highest annual total since 1991. The rise follows two deaths in Pennsylvania, the first measles fatalities in the state in 35 years. The disease can cause severe complications, especially in young children, adults over 20, pregnant individuals and those with weakened immune systems.

Infectious disease specialists say the standard two-dose measles, mumps and rubella (MMR) series provides about 97% protection and does not require routine boosters for healthy adults. > "If you’re fully vaccinated with the two-dose MMR schedule, you’re good to go," said Dr. Thomas Russo, chief of infectious diseases at the University at Buffalo. > "Measles immunity doesn’t wane the way pertussis or COVID immunity does," added Dr. Amesh Adalja, senior scholar at Johns Hopkins Center for Health Security.

Additional MMR doses may be considered for people who received an inactivated measles vaccine between 1963 and 1967, those born before 1989 who likely received only one dose, or individuals at higher risk due to travel, healthcare work, or residence in outbreak areas. People born before 1957 are presumed immune because of widespread natural infection before the vaccine era.

For those uncertain of their vaccination history, doctors recommend checking pediatric or state immunization records, or obtaining a blood test for measles antibodies. An extra MMR dose is considered safe even if immunity is already present. The vaccine can be administered by primary-care physicians, many pharmacies, or local health departments without a referral or prior lab work.

Overall, experts advise fully vaccinated individuals to continue normal activities, while encouraging anyone with unclear vaccination status to consult a healthcare provider about an additional MMR dose.