The Pandemic’s Echo: A Population-Based Assessment of MMR Rates and Associated Factors in the Wake of COVID-19

We generate a high-resolution data set on MMR vaccination coverage in the U.S. before and after the COVID-19 pandemic. We use this data to conduct a spatiotemporal analysis of vaccination patterns and uncover the associations between MMR vaccination rates and key factors such as socioeconomic conditions, COVID-19 impact, vaccine policy and other health-related variables.

Methods

We collect county-level 2-dose MMR vaccination rates for kindergarten children from 2017 – 2024 for 2,266 U.S. counties, compare coverage patterns and trends before and after the COVID-19 pandemic, and implement multivariable weighted logistic regression models to identify factors associated with low and declining MMR vaccination rates in U.S. counties.

Results

We reveal a nationwide decline in MMR rates following the COVID-19 pandemic, with declines observed in 1,688 of the counties evaluated. We find state-level non-medical exemption (NME) policies to be the strongest associated factor with low and declining MMR rates at the county level post-pandemic. We also identify a positive association between county-level MMR rates and uptake of other vaccine types, the minority proportion in a county and Republican-aligned counties. In contrast, county-level MMR rates are negatively associated with post-secondary education rates. In addition to NMEs, MMR rate declines are positively associated with the proportion of rural population and a higher religious diversity at the county level, and negatively associated with household income and the proportion of Latinx people.

Conclusions

The significant association between NMEs and low and declining MMR rates suggest these state-level policies are harmful and lead to reduced vaccination coverage post-pandemic. The positive associations among vaccine types suggest spillover effects in vaccine seeking behavior. The association between MMR rates and Republican-aligned counties contrast COVID-19 vaccination patterns, highlighting the complex nature of political polarization on vaccine-related behavior.