- Measles cases are rising across the United States.
- Doctors provide guidance for those who may have been exposed to the virus.
- Additionally, insights from infectious disease specialists about measles.
Health officials in New Jersey, Massachusetts, and Colorado have recently issued alerts regarding travelers infected with measles passing through crowded airports and other locations. Given how quickly measles can spread, it’s quite reasonable to be concerned about it.
“Measles is extraordinarily infectious—if you’re susceptible,” explains Thomas Russo, M.D., who is a professor and chief of infectious diseases at the University at Buffalo in New York.
Typically, a few measles cases appear here and there each year. Yet, this past year has seen a significant change. Nearly 2,100 individuals across 44 states have been affected by measles in 2025, according to data from the Centers for Disease Control and Prevention (CDC). This marks the highest number of cases in the last 25 years. Unfortunately, new cases keep coming in.
There keep being warnings about potential exposures, raising questions about what this might mean for you. Infectious disease doctors address some of the most pressing inquiries regarding measles, as well as what steps to take if you’ve been exposed.
Why is measles so contagious?
Many people aren’t fully aware of measles, although outbreaks happen yearly. Known as rubeola, measles is a highly contagious respiratory virus, as stated by the CDC. Symptoms can include a cough, runny nose, red and watery eyes, high fever, and spots inside the mouth.
Moreover, measles can lead to serious health issues like pneumonia and encephalitis (brain inflammation), according to the CDC.
Regarded as one of the most contagious diseases globally by the World Health Organization (WHO), the virus remains active and capable of spreading in the air or on surfaces for up to two hours. One person with measles could potentially infect up to 18 others.
The virus spreads through coughing or sneezing from an infected person, Dr. Russo explains. Infected particles can be inhaled or land on surfaces, and then, if individuals touch their eyes, nose, or mouth, they may become infected.
Infectious individuals can spread measles for four days before and after the characteristic rash appears, based on WHO information.
How can I prevent getting measles?
The measles, mumps, and rubella (MMR) vaccine prevents measles. It’s included in the childhood vaccination schedule and is given in two doses. One dose is 93% effective in preventing measles, while two doses raise that effectiveness to 97%, according to the CDC. (The MMR vaccine remains recommended for all children, despite recent updates to the CDC’s vaccination schedule.)
The first dose is typically administered between 12 and 15 months, with the second dose given between ages four and six, or when children enter school, as noted by the American Academy of Pediatrics (AAP). Adults can also receive the MMR vaccine, but the doses must be spaced 28 days apart, according to the AAP.
As a live attenuated vaccine, the MMR vaccine contains a weakened form of the virus, which helps the immune system prepare against future exposure to measles, explains John Sellick, D.O., an expert in infectious diseases and professor at the State University of New York at Buffalo.
Dr. Russo says, “The vaccine is not perfect, but it’s really pretty good.”
(However, be aware that individuals born between 1963 and 1967 received an ineffective measles vaccine during childhood, according to the CDC. If that’s you, the CDC recommends getting vaccinated again.)
Ultimately, it is possible to contract measles even if you’re fully vaccinated, but it’s not common. The vaccine is effective for about 97% of people, so around three out of 100 vaccinated individuals might still get infected. Dr. Russo mentions that some vaccinated individuals contracted the virus in recent outbreaks. Yet if you have some level of protection, you’re less likely to experience severe illness.
What to do if you’ve been exposed to measles
If you’ve been in contact with someone diagnosed with measles, try not to panic. People born before 1957 are generally considered to have “presumptive immunity,” suggesting they likely encountered the virus in childhood, according to Dr. Russo. “If you have presumptive immunity or have been vaccinated, you shouldn’t worry about measles exposure,” he notes.
Amesh A. Adalja, M.D., another infectious disease expert, also agrees: “There’s no action needed.”
If you were born after 1957 and haven’t been vaccinated or are only partially vaccinated, you still have options. While there’s no specific treatment for measles, you can receive the vaccine after exposure or an injection of immune serum globulin to provide protection against severe disease. This immune serum globulin treatment is the only option available for pregnant women, infants, and immunocompromised individuals, since the vaccine is a live virus which isn’t recommended for them, Dr. Russo explains.
If you’re unsure about your immunity but know you’ve been exposed, Dr. Russo suggests that getting vaccinated is the safest route. Dr. Sellick concurs, stating, “It’s safe to receive another dose, even if you were previously vaccinated or are already immune.”
What to do if you get measles
If you start showing symptoms of measles, reach out to your doctor (but don’t go to the office to avoid spreading it). There’s no specific treatment for measles, but your doctor might recommend immune serum globulin and supportive care such as acetaminophen for fever and fluids, along with keeping an eye out for serious complications. Ultimately, it’s best to consult a healthcare provider for guidance.
