Children’s MMR vaccine rate drops 2%, 250,000 kindergarteners vulnerable to measles: CDC

(NEW YORK) — National MMR coverage has dropped 2% from the 2019-2021 school year to the 2022-2023 school year, which means approximately 250,000 kindergartners are at risk for measles infection around the country, according to the Centers for Disease Control and Prevention.

The 93.1% rate during the 2022–23 school is 2% lower than the 95% rate in the 2019-2020 school year and leaves measles coverage below the national target of 95% for the third consecutive year.

Doctors said this nationwide trend is a concerning backdrop to measles outbreaks in Florida and Philadelphia so far this year.

Exemptions for school vaccines are also at an all-time high. Ten states now report exemptions that exceed 5%, which leaves both vaccinated and unvaccinated children vulnerable to disease outbreaks like measles, experts say.

As of Feb. 15, a total of 20 measles cases were reported by 11 jurisdictions across Arizona, California, Georgia, Maryland, Minnesota, Missouri, New Jersey, New York City, Ohio, Pennsylvania, and Virginia, according to the CDC.

A current outbreak at an elementary school in Florida has led to six kids testing positive for measles so far, school officials said. Thirty-three out of 1,067 students at the school have not received any of the two doses of the MMR vaccine, Dr. Peter Licata, the Broward County Public Schools Superintendent, noted Wednesday during a board meeting. Health care professionals were first notified of a measles case, a third grader with no travel history, on Friday February 16.

“The absence of travel history in the measles cases suggests we are likely seeing local transmission, underscoring the serious risk to the community,” Dr. John Brownstein, epidemiologist and Chief Innovation Officer at Boston Children’s Hospital and ABC News contributor, told ABC News. “Measles is highly contagious, and with its long incubation period of 11 to 12 days, there’s a high likelihood that more children are infected without showing symptoms yet. This situation is alarming and requires immediate public health intervention to prevent further spread.”

If an unvaccinated child is exposed to measles, an MMR (measles, mumps and rubella) vaccine should be given as soon as possible. It is not harmful to get MMR vaccine after being exposed to measles and doing so could prevent later disease, according to the CDC. When the MMR vaccine is given within 72 hours of initially being exposed to measles, it may provide some protection against the disease, or help someone have milder illness.

Measles can be prevented with MMR vaccine, according to the CDC. The vaccine protects against three diseases: measles, mumps, and rubella. Two doses of MMR vaccine are about 97% effective at preventing measles; one dose is about 93% effective. The first shot is recommended for kids 12-15 months old and the second is given at 4-6 years of age.

CDC data shows that an overwhelming majority of measles cases are typically among unvaccinated people. Nearly 90% of the 1,249 measles cases in 2019 – greatest number of cases reported since 1992 – were unvaccinated.

Dr. Jade A Cobern, MD, MPH, is a physician board-certified in pediatrics and preventive medicine, is a fellow of the ABC News Medical Unit.