Temporal Variations in Seroprevalence of SARS-CoV-2 Infections by Race and Ethnicity in Arkansas

To estimate SARS-CoV-2 infection rates in Arkansas, a small rural state, using SARS-CoV-2 antibody prevalence as an indicator of infection. We collected residual serum samples from adult outpatients seen at hospitals or clinics in Arkansas for non-COVID-19-related reasons. A total of 5,804 samples were identified over three time periods: August 15-September 5 (time period 1), September 12-October 24 (time period 2), and November 7-December 19, 2020 (time period 3). The age, sex, race, and ethnicity standardized SARS-CoV-2 seroprevalence extrapolated the increase in infection during each period, from 2.6% in time period 1 to 4.1% in time period 2 and 7.4% in time period 3. No statistically significant difference in seroprevalence was found based on age, sex, or residence (urban vs. rural). However, we found higher seroprevalence rates in each time period for Hispanics (17.6%, 20.6%, and 23.4%, respectively) and non-Hispanic (NH) Blacks (4.8%, 5.4%, and 8.9%, respectively) relative to NH Whites (1.1%, 2.6%, and 5.5%, respectively). Our data imply that the number of Arkansas residents infected with SARS-CoV-2 rose steadily from 2.6% in August to 7.4% in December 2020. There was no statistical difference in seroprevalence between rural and urban locales. Hispanics and Blacks had higher rates of SARS-CoV-2 antibodies than Whites, indicating that SARS-CoV-2 spread disproportionately in racial and ethnic minorities during the first year of the COVID-19 pandemic.