Coronavirus disease 2019 population-based prevalence, risk factors, hospitalization, and fatality rates in southern...

To assess population-based prevalence, risk factors, hospitalization, and infection fatality rates (IFR) associated with COVID-19.

We conducted two household surveys among the non-institutionalized adult population from May 30 to June 17, 2020, in Lajeado, an 84,000-inhabitant industrial city in southern Brazil. Primary outcome was prevalence of SARS-CoV-2 infection. Secondary outcomes were COVID-19-related hospitalizations and deaths occurring up to June 20, 2020. We summarized prevalence rates across surveys with meta-analysis. We assessed age-range IFR and hospitalization rate and regressed these rates over age strata using nonlinear (exponential) coefficients of determination (R²).

Summarized overall prevalence was 3.40% (95% CI, 2.74-4.18), 34% lower in older adults ≥60 years. Prevalence was 14.3 and 5.4 times higher among household contacts and meat-precessing plant (MPP) workers, respectively. IFR ranged from 0.08% (0.06-0.11) to 4.63% (2.93-7.84) in individuals 20-39 years and ≥60 years, respectively. R² for hospitalization rate and IFR over age were 0.98 and 0.93 (both p-values <0.0001), respectively.

This is the first population-based study in Brazil to estimate COVID-19 prevalence, hospitalization, and fatality rates per age stratum. Rates were largely age-dependent. Household contacts and MPP workers are at higher risk of infection. Our findings are valuable for health-policy making and resource allocation to mitigate the pandemic.