Long COVID Prevalence among U.S. Adults: A State-level Ecological Analysis of the Contribution of COVID-19 Incidence, Severity of Acute Illness, COVID-19 Vaccination, and Chronic Conditions

BackgroundLong COVID has emerged as a major public-health concern in the United States, yet geographic variation in its prevalence remains poorly understood. This study examines how state-level differences in COVID-19 vaccination, SARS-CoV-2 incidence, COVID-19 hospitalization, and chronic disease burden relate to adult Long COVID prevalence in the United States. MethodsWe conducted an ecological analysis using data from the 2023 Behavioral Risk Factor Surveillance System (BRFSS), from which we estimated state-level prevalence of self-reported Long COVID among adults. These estimates were linked with publicly available data on SARS-CoV-2 incidence, COVID-19 hospitalizations, COVID-19 vaccine coverage, and a multimorbidity indicator (>= 3 chronic conditions e.g., diabetes, obesity, chronic kidney disease) associated with higher risk for severe SARS-CoV-2. Multivariable linear regression models were fitted to assess the contribution of each factor adjusted for age and sex distribution, incorporating Rubins rules to account for uncertainty in prevalence estimates. ResultsAll examined factors--including SARS-CoV-2 incidence, hospitalization rates, and multimorbidity, vaccine coverage--varied by state. When modeled simultaneously and adjusting for age and sex distribution, only COVID-19 vaccine coverage and SARS-CoV-2 incidence were significantly associated with Long COVID prevalence. COVID-19 vaccine coverage showed a strong protective association, while SARS-CoV-2 incidence showed a modest positive association. Multimorbidity and hospitalization rates were not independently associated with adjustment. ConclusionsState-level variation in Long COVID burden appears most strongly driven by COVID-19 vaccine coverage and SARS-CoV-2 incidence. Promoting COVID-19 vaccination remains essential to reduce long-term impacts from SARS-CoV-2 infections.