Measles is a virus infection that causes symptoms much like that of a bad cold or flu such as a cough, fever, runny nose and a rash. In some cases, it can cause ear infections, pneumonia or encephalitis (brain swelling) and death. It can spread easily because the virus can linger in the air for up to two hours after an infected person coughs or sneezes. Plus, people are infectious up to four days before they even know they have it.
The CDC recommends routine vaccination for measles in the form of the MMR (measles, mumps and rubella) vaccine with the first dose given at ages 12 to 15 months, and a second dose between ages 4 and 6. The vaccine is 97% effective when both doses are received. When everyone gets vaccinated, it protects those who are vulnerable to complications from this infection, such as children too young to get vaccinated, the elderly and those with a medical condition that prevents them from receiving the vaccine.
Being properly vaccinated is particularly important for travelers. Measles is a common disease in many other countries and a contributing factor to the resurgence of the disease is unvaccinated international travelers.