If you've already been vaccinated for measles, do you need to get a booster now that it's spreading in the US?

Amid one of the largest measles outbreaks in the United States in nearly a decade, anti-vaccine activists are promoting false claims that shots are ineffective in stemming the spread of the virus or that they could cause the disease.

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

The United States declared measles eradicated in 2000 because the disease was no longer spreading locally (most cases in the following years were linked to travel to countries whe