Prevalence of current and past COVID-19 in Ohio adults

Purpose To estimate the prevalence of current and past COVID-19 in Ohio adults. Methods We used stratified, probability-proportionate-to-size cluster sampling. During July 2020, we enrolled 727 randomly-sampled adult English- and Spanish-speaking participants through a household survey. Participants provided nasopharyngeal swabs and blood samples to detect current and past COVID-19. We used Bayesian latent class models with multilevel regression and poststratification to calculate the adjusted prevalence of current and past COVID-19. We accounted for the potential effects of non–ignorable non–response bias. Results The estimated statewide prevalence of current COVID-19 was 0.9% (95% credible interval: 0.1%–2.0%), corresponding to ∼85,000 prevalent infections (95% credible interval: 6,300–177,000) in Ohio adults during the study period. The estimated statewide prevalence of past COVID-19 was 1.3% (95% credible interval: 0.2%–2.7%), corresponding to ∼118,000 Ohio adults (95% credible interval: 22,000–240,000). Estimates did not change meaningfully due to non–response bias. Conclusions Total COVID-19 cases in Ohio in July 2020 were approximately 3.5 times as high as diagnosed cases. The lack of broad COVID-19 screening in the United States early in the pandemic resulted in a paucity of population-representative prevalence data, limiting the ability to measure the effects of statewide control efforts.