Measles cases are on the rise. Here’s what Mass. residents need to know

Measles is exceedingly rare in Massachusetts. Not a single case was reported for four of the last five years. But in late February, state officials had identified two cases in Massachusetts residents — one child and one adult.

Both people were infected outside the state.

Measles outbreaks are growing in other parts of the country and around the globe. The U.S. Centers for Disease Control and Prevention identified 1,136 cases of measles in the first two months of this year, mostly in South Carolina, Utah and Florida. The vast majority of those cases were among unvaccinated people, according to federal data.

Measles spread is most dangerous in places where the population is less likely to be vaccinated, but the impacts are not limited to those places.

“The more cases there are globally, the more chances are that we're going to continue to be affected by them,” said Dr. Catherine Brown, the state epidemiologist for Massachusetts.

In 2025, there were 2,281 confirmed cases of measles in the U.S. and three deaths due to the disease. The death rate is much higher in lower-income countries with lower vaccination rates. And nearly a third of cases lead to serious — and sometimes long-term — complications.

The growing spread of this preventable, highly contagious disease comes as Trump administration officials have undermined confidence in routine childhood vaccines, weakened recommendations and sought to restrict access.

Here’s what to know about the resurgence of measles:

Didn’t we eliminate this disease?

Officially – yes. In 2000, the U.S. reached measles elimination status, a designation that signifies no large outbreaks or uncontrolled spread of the disease. That status is now under threat.

“Something that we have so effectively addressed as a public health problem — it’s hard to see it come back,” Brown said, “particularly when we know that it can be such a severe disease.”

Who does measles affect?

Children are most at risk — particularly, young infants, because the first dose of vaccine typically is not given until a child’s first birthday. People who are immunocompromised or elderly are also at higher risk of severe disease, said Dr. Daniel Kuritzkes, senior physician in the division of infectious diseases at Mass General Brigham.

The measles vaccine is very effective at preventing disease over the course of a person’s lifetime, he said. If a vaccinated person does get measles? “They’re much less likely to have a severe case,” Kuritzkes said.

What are the signs of measles?

It can seem like a cold at first, with symptoms including fever, runny nose and cough. After a few days, a rash develops, spreading from the face downward through the body.

Measles can be mild. But about 30% of infected people get complications like pneumonia, immune suppression, brain swelling or, more rarely, lasting brain damage.

The measles virus is also extremely contagious. Nine out of 10 unvaccinated people who come in contact with an infected person will contract measles. It spreads through tiny particles that can remain in the air for up to two hours after an infected person leaves a room. People can spread measles before they know they are sick.

“Unlike influenza or COVID, we don’t have any specific treatment for measles,” Kuritzkes said. “All we can do is help people feel more comfortable.”

What is the risk to Massachusetts residents?

In Massachusetts, the overall risk remains low because the vast majority of residents are vaccinated against measles.

Generally, experts say vaccination rates must be at least 95% to prevent outbreaks. Data from the state Department of Public Health shows 98% of Massachusetts children have received a measles vaccine, called the MMR. The shot also protects against two other diseases, mumps and rubella. The state vaccination rate is higher than the U.S. average of 92%.

However, vaccination rates can vary across communities, and even in Massachusetts, pediatricians say more parents are becoming skeptical of vaccines.

Will we see additional cases?

More cases of measles are certainly possible, given the increasing numbers of cases in other states. The level of measles in the U.S. now is the highest in more than three decades.

But Kuritzkes said he would be surprised to see a local outbreak given Massachusetts’s relatively high vaccination rates.

“We just have to be vigilant and watch carefully,” he said.

What’s the best way to protect against measles?

Public health officials and doctors say vaccination is the best protection. The American Academy of Pediatrics recommends children receive one dose of MMR vaccine when they’re 12 to 15 months old, and a second dose between age 4 and 6. Babies sometimes receive a first dose of the MMR vaccine before 12 months if they’re scheduled to travel to places where they might be exposed.

The MMR vaccine is 97% effective at preventing measles. (Another option is the four-combination MMRV, which also protects against chickenpox.)

The shots are considered safe for most adults, too. Adults who are uncertain of their vaccination status can request a blood test to check their immunity, said Brown, of the Department of Public Health. People born before 1957 are likely to have immunity from getting measles as children.

“For individuals who are vaccinated, and their whole family is vaccinated, the risk is really quite minimal,” Brown said.

“Most people in Massachusetts don’t have to do anything,” she added, “except have a background level of awareness about the fact that these diseases that we had pretty much eliminated from circulation in the U.S. are creeping back up.”