The Pandemic's Echo: A Population-Based Assessment of MMR Rates and Associated Factors in the Wake of COVID-19
Authors:Ensheng Dong, Samee Saiyed, Andreas Nearchou, Yamato Okura, Lauren M. Gardner
Objectives: 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.
