Measles continues to pop up across the US: The Centers for Disease Control and Prevention (CDC) has advised health care providers to stay alert for measles symptoms in their patients after a string of cases were confirmed, largely in kids who had not been vaccinated against the disease, in early 2024.
In Philadelphia, nine people recently tested positive for measles after an outbreak began at a children’s hospital and spread to a daycare center. In January public health officials in Virginia warned that a person with a confirmed case of measles had traveled through northern areas of the state, including major airports, after returning from an international trip. Washington state, New Jersey, and Georgia health officials also reported measles cases in January.
The viral infection also seems to be surging abroad, especially in Europe, according to the World Health Organization (WHO). In a statement released late last year, the WHO called the trend “alarming,” as reported cases in the region jumped from 941 in 2022 to more than 30,000 in 2023.
In 2000, measles was officially “eliminated” from the United States, meaning the disease is no longer consistently present—but, as we’ve seen more and more, the virus still pops up and causes concerning outbreaks. Given that measles is a highly contagious disease that can cause gnarly symptoms, it’s understandable if you have questions about how to stay safe. “Booster” vaccines are common practice for viral illnesses like the flu and COVID-19, so should you ask about the same for measles? Here’s what to keep in mind if there’s a cluster of cases near you.
First, a little bit about how the MMR vaccine works.
The measles, mumps, and rubella (MMR) vaccine is an attenuated live virus vaccine. That means it contains weakened viruses that cause a harmless infection in a person receiving the shot. This can trigger few (if any) symptoms before the viruses are eradicated from the person’s body, as the CDC explains. During this process, your immune system works hard to produce specific infection-fighting antibodies, so if you happen to come across the virus that causes measles in the future, your body remembers how to respond to it swiftly.
“This is a remarkably effective vaccine,” William Schaffner, MD, an infectious disease specialist and professor of preventive medicine at the Vanderbilt University School of Medicine in Nashville, tells SELF. Just one dose of the shot is 93% effective against measles, while the recommended two doses offer 97% protection.
The MMR vaccine should be baked into your childhood immunization schedule. It’s recommended that kids get the first dose between the ages of 12 to 15 months and the second between the ages of four and six. “If you attend public school in the US, you typically need to have had the MMR vaccine,” Dr. Schaffner says. However, some private schools do not require the MMR vaccine, and it’s possible to reach adulthood without receiving it, he notes.
Do certain people need a measles booster?
If you’re fully vaccinated—again, two doses—you should have lifelong protection against measles. “There’s no recommendation for boosting individuals during outbreaks,” Amesh A. Adalja, MD, infectious disease specialist and senior scholar at the Johns Hopkins Center for Health Security, tells SELF.