Measles vaccine rates of children fall in most counties, study shows

Measles vaccination rates among U.S. children have dropped in recent years, falling below the “herd immunity” threshold needed to prevent outbreaks, according to a new Johns Hopkins study. National coverage declined from nearly 94% in 2018 to just over 91% in the most recent school year. 

As health officials monitor the trend, the U.S. Centers for Disease Control and Prevention (CDC) has updated its travel guidance and now urges all international travelers to be vaccinated against measles, regardless of their destination.

Newly released study cites drop in vaccination rates 

The study used county-level data from 33 states, relying on publicly available information. The study found that MMR (measles-mumps-rubella) vaccination rates dropped among school-aged children. According to the data, vaccination rates between the 2017-2018 school year were 93.92%. The rates dropped to 91.26% in the 2023-2024 school year.