ABSTRACT
Background and ObjectivesCase-based surveillance of pediatric COVID-19 cases underestimates the prevalence of SARS-CoV-2 infections among children and adolescents. Our objectives were to: 1) estimate monthly SARS-CoV-2 antibody seroprevalence among children aged 0-17 years and 2) calculate ratios of SARS-CoV-2 infections to reported COVID-19 cases among children and adolescents in 14 U.S. states. MethodsUsing data from commercial laboratory seroprevalence surveys, we estimated monthly SARS-CoV-2 antibody seroprevalence among children aged 0-17 years from August 2020 through May 2021. Seroprevalence estimates were based on SARS-CoV-2 anti-nucleocapsid immunoassays from February to May 2021. We compared estimated numbers of children infected with SARS-CoV-2 by May 2021 to cumulative incidence of confirmed and probable COVID-19 cases from case-based surveillance, and calculated infection: case ratios by state and type of anti-SARS-CoV-2 nucleocapsid immunoassay used for seroprevalence testing. ResultsAnalyses included 67,321 serum specimens tested for SARS-CoV-2 antibodies among children in 14 U.S. states. Estimated ratios of SARS-CoV-2 infections to reported confirmed and probable COVID-19 cases among children and adolescents varied by state and type of immunoassay, ranging from 0.8-13.3 in May 2021. ConclusionsThrough May 2021, the majority of children in selected states did not have detectable SARS-CoV-2 nucleocapsid antibodies. Case-based surveillance underestimated the number of children infected with SARS-CoV-2, however the predicted extent of the underestimate varied by state, immunoassay, and over time. Continued monitoring of pediatric SARS-CoV-2 antibody seroprevalence should inform prevention and vaccination strategies.
ABSTRACT
BackgroundDuring the 2020-2021 academic year, many institutions of higher education reopened to residential students while pursuing strategies to mitigate the risk of SARS-CoV-2 transmission on campus. Reopening guidance emphasized PCR or antigen testing for residential students and social distancing measures to reduce the frequency of close interpersonal contact. Connecticut colleges and universities employed a variety of approaches to reopening campuses to residential students. MethodsWe used data on testing, cases, and social contact in 18 residential college and university campuses in Connecticut to characterize institutional reopening strategies and COVID-19 outcomes. We compared institutions fall 2020 COVID-19 plans, submitted to the Connecticut Department of Public Health, and analyzed contact rates and COVID-19 outcomes throughout the academic year. ResultsIn census block groups containing residence halls, fall student move-in resulted in a 475% (95% CI 373%-606%) increase in average contact, and spring move-in resulted in a 561% (441%-713%) increase in average contact. The relationship between test frequency and case rate per residential student was complex: institutions that tested students infrequently detected few cases but failed to blunt transmission, while institutions that tested students more frequently detected more cases and prevented further spread. In fall 2020, each additional test per student per week was associated with a reduction of 0.0014 cases per student per week (95% CI: -0.0028, -0.000012). Residential student case rates were associated with higher case rates in the town where the school was located, but it is not possible to determine whether on-campus infections were transmitted to the broader community or vice versa. ConclusionsCampus outbreaks among residential students might be avoided or mitigated by frequent testing, social distancing, and mandatory vaccination. Vaccination rates among residential students and surrounding communities may determine the necessary scale of residential testing programs and social distancing measures during the 2021-2022 academic year.
