SARS-CoV-2 Infection Hospitalization Rate and Infection Fatality Rate Among the Non-Congregant Population in Connecticut

Mahajan, Shiwani; Caraballo, César; Li, Shu-Xia; Dong, Yike; Chen, Lian; Huston, Sara K.; Srinivasan, Rajesh; Redlich, Carrie A.; Ko, Albert I.; Faust, Jeremy S.; Forman, Howard P.; Krumholz, Harlan M.

BACKGROUND: Infection fatality rate and infection hospitalization rate, defined as the proportion of deaths and hospitalizations, respectively, of the total infected individuals, can estimate the actual toll of COVID-19 on a community as the denominator is ideally based on a representative sample of a population, which captures the full spectrum of illness, including asymptomatic and untested individuals. OBJECTIVE: To determine the COVID-19 infection hospitalization rate and infection fatality rate among the non-congregate population in Connecticut between March 1 and June 1, 2020. METHODS: The infection hospitalization rate and infection fatality rate were calculated for adults residing in non-congregate settings in Connecticut before June 2020. Individuals with SARS-CoV-2 antibodies were estimated using the seroprevalence estimates from the recently conducted Post-Infection Prevalence study. Information on total hospitalizations and deaths was obtained from the Connecticut Hospital Association and the Connecticut Department of Public Health. RESULTS: Before June 1, 2020, nearly 113,515 (90% CI 56,758–170,273) individuals were estimated to have SARS-CoV-2 antibodies and there were 7792 hospitalizations and 1079 deaths among the non-congregate population. The overall COVID-19 infection hospitalization rate and infection fatality rate was 6.86% (90% CI, 4.58%–13.72%) and 0.95% (90% CI, 0.63%–1.90%) and there was variation in these rate estimates across subgroups; older individuals, men, non-Hispanic Black individuals, and those belonging to 2 of the counties had a higher burden of adverse outcomes, though the differences between most subgroups were not statistically significant. CONCLUSIONS: Using representative seroprevalence estimates, the overall COVID-19 infection hospitalization rate and infection fatality rate were estimated to be 6.86% and 0.95%, respectively, among community residents in Connecticut.