Prevalence of SARS-CoV-2 Infection among Children and Adults in 15 US Communities

Abstract

During January–August 2021, the Community Prevalence of SARS-CoV-2 Study used time/location sampling to recruit a cross-sectional, population-based cohort to estimate SARS-CoV-2 seroprevalence and nasal swab sample PCR positivity across 15 US communities. Survey-weighted estimates of SARS-CoV-2 infection and vaccine willingness among participants at each site were compared within demographic groups by using linear regression models with inverse variance weighting. Among 22,284 persons >2 months of age and older, median prevalence of infection (prior, active, or both) was 12.9% across sites and similar across age groups. Within each site, average prevalence of infection was 3 percentage points higher for Black than White persons and average vaccine willingness was 10 percentage points lower for Black than White persons and 7 percentage points lower for Black persons than for persons in other racial groups. The higher prevalence of SARS-CoV-2 infection among groups with lower vaccine willingness highlights the disparate effect of COVID-19 and its complications. As of May 2023, ≈104 million confirmed SARS-CoV-2 cases had been reported in the United States (1). That case count is certainly an underestimate, given the occurrence of asymptomatic disease; self-testing and unreported cases; and limited initial diagnostic testing, especially among children. The true case count may be gleaned from SARS-CoV-2 seroprevalence studies. In most parts of the world, including the United States, many prevalence estimates have been based on convenience samples of adults (2), including samples from healthcare settings (3) or from US commercial laboratories (4). According to those approaches, seroprevalence has varied from 10% to 58%, depending on the type of serologic test used, calendar time in relation to the pandemic, population sampling strategy, and characteristics of the population (e.g., demographic, clinical, and healthcare seeking) (3,4). Population-based seroprevalence estimates from nonclinical general populations have been few (5), reflecting challenges posed by the COVID-19 pandemic with regard to rigorous sampling strategies for reaching representative populations (6–9). Some strategies have used social media to recruit diverse populations but lacked a well-defined sampling frame (10), and regional studies with random sampling schemes have lacked diverse participation (11–13). In addition, many seroprevalence studies have not included detailed demographic and socioeconomic information about the participants despite the association of those factors with SARS-CoV-2 infection (14–17). We report the results of the Community Prevalence of SARS-CoV-2 Study (COMPASS), which was conducted in the first half of 2021 to assess prevalence of prior and current SARS-CoV-2 infection among the general population of adults and children in largely urban communities surrounding established clinical research sites in the United States. We based determination of infection on antibody and PCR positivity. We also describe the population-level factors associated with increased risk for SARS-CoV-2 infection. COMPASS used time/location sampling (TLS) as a rigorous method of nonprobability sampling of public venues near the participating research sites to enroll persons from the community (18,19). To improve the representativeness of the general population sample given the mobility restrictions of the pandemic, COMPASS also recruited a clinical cohort from outpatient healthcare facilities and a nursing home cohort from residential facilities for older adults.