Dataset Shows MMR Vaccination Rates Declined Since Start of COVID Pandemic

Researchers with Johns Hopkins University have produced a national dataset showing a countrywide “decline in the measles, mumps, and rubella (MMR) vaccination rate among children since the start of the COVID-19 pandemic.” CIDRAP has the news.

The study comes in the midst of one of the U.S.’s largest measles outbreaks in the post-elimination era, “with more than 1,100 cases reported since the first of the year,” as HPN has reported on.

The dataset “considered annual county-level vaccination rates for kindergarten-age children during the 2017-2018 and 2023-2024 school years. In states in which that data wasn’t available, the authors used the most comparable proxy, either 2-dose MMR vaccination rates for kindergarten through grade-12 students or 5- to 6-year-old's completion rates for a combined vaccine series that included the 2-dose MMR vaccine.” Across the 2,066 counties within 33 states, the “county-level mean vaccination rate decreased from 93.92% (5.71%) prepandemic to 91.26% (6.95%) postpandemic, a mean decline of 2.67%.” Of those counties, “1,614 (78%) showed a decline in MMR coverage.”

The authors said the dataset could be used “to identify factors associated with low or declining MMR rates in US counties and help inform targeted vaccination strategies to reduce the risk of measles outbreaks.”