About three out of 100 people who get both doses of the MMR vaccine will still get measles if they’re exposed to the virus, according to the CDC. “If someone does get measles after vaccination, the disease is typically milder than if someone who is unvaccinated acquires the infection,” Dr. Kulkarni says.

Vaccination provides long-lasting 97% protection against measles infection. Most people who have been vaccinated do not need to be vaccinated again.

A recent outbreak of measles is prompting questions about the life-threatening disease and how to prevent it. Here's what to know.