Measles and Cancer Treatment: How to Stay Protected

Measles and cancer treatment are a bad combination for two reasons. Measles is one of the most contagious infections known. And many cancer treatments weaken the immune system that would normally fight it off. During an outbreak, measles becomes a real planning concern for people in treatment, not just a news story.

The good news is that protection is mostly logistics: vaccination for the people around you, avoiding exposures during vulnerable stretches, and acting fast if an exposure happens.

The CDC's numbers explain the concern. Suppose a person has measles. Up to 90 percent of the non-immune people close to them will also become infected. The virus spreads when an infected person coughs or sneezes. It can live for up to two hours in an airspace. So you can catch it from a room the sick person has already left.

Timing makes it harder to dodge. An infected person can spread measles from 4 days before their rash appears through 4 days after. In other words, people are contagious before they know they are sick.

NCI explains that some cancer treatments, especially chemotherapy, lower the number of white blood cells. Those are the cells that help your body fight infection. Neutrophils, a key type, drop during treatment cycles. NCI is direct about the stakes. Infections during cancer treatment can be life threatening, and they require urgent medical attention.

A vaccine given years ago may still help. But your care team is the right judge of how protected you are now. Some treatments blunt the immune system more than others. If it is worth knowing, immunity can be checked with a blood test.

The MMR vaccine is highly effective. CDC reports that two doses are 97 percent effective against measles, and one dose is 93 percent effective.

But MMR is a live vaccine, made from weakened virus. CDC says people who have a weakened immune system due to disease or medical treatments should not get it. For many people in active treatment, that closes the direct route to protection for now. Whether and when a vaccine fits around your treatment is a decision for your cancer team.

NCI adds a related caution. Avoid crowds, and stay away from people who have just had a live vaccine, such as one for chicken pox, polio, or measles. Is someone in your household due for a live vaccine? Ask your team how to handle it rather than guessing.

When you cannot be vaccinated, your protection is built from the immunity of the people around you. CDC says household members and other close contacts of people who are immunocompromised should have evidence of MMR vaccination.

So families have a concrete question for the care team. Which household members need MMR, and how many doses? Ask how that applies to your household. Then add the everyday layers NCI recommends during treatment. Wash hands often and well with soap and warm water, especially before eating. Stay away from people who are sick, above all when your counts are low.

CDC says to call your healthcare provider immediately if you think you were exposed. Call your cancer team right away. Two facts set the clock:

• CDC notes that people at high risk of severe disease may be given a medicine called immune globulin (IG) within 6 days of being exposed to measles.
• MMR vaccine within 72 hours of exposure may give some protection to people who can receive it. During immune-suppressing treatment, that option is generally off the table. That makes the IG window the one that matters.

Call your cancer team before going anywhere in person. They can decide whether you need IG and arrange testing. They can also plan any visit so you are not sharing a waiting room in the meantime.

Watch the calendar afterward. CDC says measles symptoms appear 7 to 14 days after contact with the virus. They typically start with high fever, cough, and runny nose. A rash follows 3 to 5 days after symptoms begin.

Some situations cannot wait for a routine call. Use these rules to decide how fast to act.

• Call your cancer team immediately, any hour, if your temperature reaches 100.4 °F (38 °C) or higher during treatment. NCI's infection page uses 100.5 °F, but 38 °C is 100.4 °F, so act at 100.4. The threshold exists because infections during treatment can turn serious quickly. The same immediate call applies if someone in your home has a fever and rash.
• Call your cancer team right away if you learn you were exposed to measles, even with no symptoms at all. The 6-day immune globulin window closes fast.
• Say so first if you have a fever with a rash and are heading to any clinic or emergency department. Calling ahead lets staff keep you from exposing others and protects you from shared waiting areas.
• Do not wait out new cough, runny nose, and fever in the days after a possible exposure. Report them and let your team decide.

• How Measles Spreads — Centers for Disease Control and Prevention
• Measles Signs and Symptoms — Centers for Disease Control and Prevention
• Measles Vaccination — Centers for Disease Control and Prevention
• Infection and Neutropenia During Cancer Treatment — National Cancer Institute