SARS-CoV-2 Seroprevalence Compared with Confirmed COVID-19 Cases among Children, Colorado, USA, May-July 2021

Abstract

To compare SARS-CoV-2 antibody seroprevalence among children with seropositive confirmed COVID-19 case counts (case ascertainment by molecular amplification) in Colorado, USA, we conducted a cross-sectional serosurvey during May-July 2021. For a convenience sample of 829 Colorado children, SARS-CoV-2 seroprevalence was 36.7%, compared with prevalence of 6.5% according to individually matched COVID-19 test results reported to public health. Compared with non-Hispanic White children, seroprevalence was higher among Hispanic, non-Hispanic Black, and non-Hispanic other race children, and case ascertainment was significantly lower among Hispanic and non-Hispanic Black children. This serosurvey accurately estimated SARS-CoV-2 prevalence among children compared with confirmed COVID-19 case counts and revealed substantial racial/ethnic disparities in infections and case ascertainment. Continued efforts to address racial and ethnic differences in disease burden and to overcome potential barriers to case ascertainment, including access to testing, may help mitigate these ongoing disparities.

Keywords: 2019 novel coronavirus disease; 2019 novel coronavirus infection; 2019-nCoV; COVID-19; Colorado; SARS-CoV-2; SARS-CoV-2 infection; United States; antibody testing; coronavirus disease; diagnostic testing; pandemic; respiratory infections; serologic testing; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.

Figure 1

Days between first positive diagnostic test result and sample collection for serology testing for SARS-CoV-2 IgG, Colorado, USA, May 12–July 13, 2021. N, nucleocapsid; S, spike.

Figure 2

Boxplots showing number of previous tests, by racial/ethnic and age groups, among 829 children included in seroprevalence and case ascertainment analyses, Colorado, USA, May 12–July 13, 2021. NH, non-Hispanic.