Maryland is well protected from measles, mumps and rubella, despite some declines in vaccination rates compared to the beginning of the pandemic.

The data comes from a new study from Johns Hopkins University that shows a 2.7% decrease in vaccination rates for the diseases across 33 states.

The decreases bring the average vaccination rate from about 94% to about 91.3%, raising concerns about the potential for outbreaks.

“Measles is very infectious and requires what’s called a herd immunity threshold of around 95%,” said Lauren Gardner, director of Johns Hopkins University’s Center for Systems Science and Engineering. “That means you want about 95% of a population to be protected through vaccination to prevent outbreaks of measles happening in that location.”

The study looks at vaccination rates by county. All of Maryland’s counties hit the 95% threshold. However, that was not the case in many jurisdictions across the nation.

Gardner said some counties’ rates dropped as much as 15% since before the pandemic.

“Hawaii had coverage that was pretty good, hovering around 95%,” Gardner said. “The average rate after COVID, is hovering closer to 80% which is obviously far below the herd immunity threshold that we would want.”

This year several cases of measles have been reported in Maryland. All of those incidents were due to residents traveling internationally.

However, places like Texas have seen large outbreaks. The total U.S. count for measles this year is over a thousand cases.