Most adults who were vaccinated as children don’t need to get the MMR vaccine again, with few exceptions. If you’re not sure whether you got the vaccine, talk to your doctor first.
Nearly 25 years ago, public health officials declared that measles had been eliminated in the United States. Today, however, due to declining vaccination rates, measles is spreading again.
Mini Kamboj, MSK’s Chief Medical Epidemiologist, explains what people with cancer and their caregivers need to know about measles and the MMR (measles, mumps, and rubella) vaccine.
Mini Kamboj
Measles spreads easily.
Measles spreads through the air when an infected person breathes, coughs, or sneezes. Symptoms include fever, rash, red eyes, and breathing problems. Measles can spread for several days before and after the rash appears.
Measles is making a comeback in the United States.
As of early March 2025, the United States is facing a large measles outbreak. Over 160 cases have been reported in 9 states, including a few cases in New Jersey and New York. More than 93% of cases are linked to an outbreak in Texas. One unvaccinated child in Texas died — the first U.S. measles-related death in more than a decade — and about 20% of patients have needed hospital care. Health officials warn that more cases are likely.
Measles is especially dangerous for people with cancer.
If you have cancer and a weakened immune system, measles can lead to serious health problems. The most serious risks are if the disease spreads to the brain (encephalitis) or to the lungs (pneumonitis). There is no proven treatment for measles.
Measles symptoms can be different for people with cancer.
The main symptoms of measles are fever, cough, runny nose, rash, and red watery eyes. But if you have a weakened immune system, you might not have a fever or only have a mild one. The rash can also be different — either more or less severe.
MMR vaccine in childhood gives long-term protection against measles.
The MMR vaccine has been a routine childhood vaccination in the United States since 1968 and can prevent people from ever getting measles, with a few exceptions. You’re also protected for life if you had measles as a child. Most people born before 1957 (before the current vaccine was available) are likely to have had measles in childhood and are considered immune.
The MMR vaccine is very effective. One dose is about 93% effective, and 2 doses (which are recommended) are 97% effective at preventing measles. It’s very uncommon for fully vaccinated people to get measles. If they do, the illness is more mild and less likely to spread to others.
Most people with cancer can’t get the MMR vaccine.
If you are actively undergoing chemotherapy or about to start treatment or have certain types of cancer on observation only, you cannot get the vaccine. The MMR vaccine is a live vaccine, which means that it contains a weakened version of the measles virus and builds immunity by creating a very mild form of infection in the body. For those with a weakened immune system, this can be risky.
People who were treated for cancer usually don’t need the vaccine again.
Most adults who were vaccinated as children don’t need to get the MMR vaccine again, with few exceptions. If you’re not sure whether you got the vaccine, talk to your doctor first. They can help you understand your risk and see if the vaccine is safe for you. People with certain types of cancer may be able to get the vaccine if they are no longer on active therapy and their immune system has recovered. You should always check with your MSK care team before you get a vaccine.
People who have had a bone marrow or stem cell transplant do need to get vaccinated again, because they lose immunity to vaccines they previously received. The MMR vaccine is generally given no sooner than 2 years after a transplant but can be even longer in some patients.
If you can’t get vaccinated, there are still ways to protect yourself from measles.
If you have cancer and a weakened immune system, you should avoid traveling to places with ongoing measles outbreaks. Wash your hands often and avoid being around people who are sick with fever, rash, cough, runny nose, or red eyes.
Because people with cancer might not be able to get the MMR shot, it’s important that everyone around them is vaccinated. This helps keep them safe. Whether they are traveling or staying home, all close contacts of people with cancer should be up to date on the MMR vaccine to help protect the patient.
Household members can safely get the MMR vaccine.
It is safe for people with cancer to be around caregivers, children, or grandchildren who just got the MMR vaccine. Even though MMR is a live vaccine, the strain used in the vaccine does not spread between people. You do not need to avoid contact.
It’s important to stay informed.
Check the Centers for Disease Control and Prevention (CDC) and your state’s health department websites for the latest updates.
