Philadelphia measles outbreak sparks false claims about vaccine efficacy

Five children and one adult in Philadelphia have been infected with measles. The outbreak began at Philadelphia’s top children’s hospital and spread after an infected patient attended a daycare center where some children were too young to receive the MMR (measles-mumps-rubella) vaccine, despite quarantine requirements. Some commenters on articles about the outbreak falsely claimed that the MMR vaccine is unnecessary and ineffective.

Risk level: Low

Recommendation: These types of comments may discourage patients in the Northeast from vaccinating their children against measles. It is recommended doctors in the Northeast be prepared to answer questions about the efficacy and necessity of the MMR vaccine. Talking points may emphasize that measles can cause serious complications, especially in children, including pneumonia, encephalitis, hospitalization, and death. Two doses of the MMR vaccine are about 97 percent effective at preventing measles. The CDC recommends that children receive their first dose of the MMR vaccine at 12 to 15 months old and their second dose at four to six years old.