How the measles vaccine keeps kids from getting sick

The growing measles outbreak that has sickened at least 198 people and led to 1 child’s death is happening in one of Texas’s least vaccinated counties. Only 82% of kindergartners in Gaines County are up-to-date on their measles-mumps-rubella (MMR) vaccines, according to state health records , compared to 94.3% statewide . That’s likely an overestimate, experts say, since it doesn’t include children who are homeschooled or attend private schools. Before American scientist John Enders and colleagues developed the measles vaccine in 1963, the virus was a common childhood infection in the US. Caused by a morbillivirus, measles spreads rapidly and causes symptoms such as fever, rash, sore throat, and bronchitis. While the condition can be relatively mild, 1 in 5 of those infected will require hospitalization, and 1 in 20 develop pneumonia . A smaller proportion can develop brain swelling known as encephalitis. Approximately 1 to 3 out of every