Measles, also called rubeola, is a highly contagious illness caused by a virus. It starts with fever that gets worse over several days, cough, runny nose, and watery, red eyes. After a few days a rash develops and lasts up to a week. Then it gets better by itself. Some people get a more serious case of measles which can cause diarrhea, middle ear infection, pneumonia (lung infection) or encephalitis (brain infection).

Measles illness during pregnancy can cause early labor, miscarriage, and low birth weight infants. Measles in people with AIDS or weak immune systems can be very severe. In the United States, 2 out of 1000 people who get measles will die from it, usually from the complications of the pneumonia or encephalitis caused by the infection.

Measles is prevented through vaccination. Before there was a vaccine, it is estimated that there were over 3 million measles cases every year in the US, and 500 deaths due to measles. The vaccine that we use today, called MMR, for measles, mumps and rubella, is highly effective. Measles vaccination protects not just the person being vaccinated, but the community around them, including babies less than 12 months old who are too young to be vaccinated.