Blood donor surveillance of SARS-CoV-2 seroreactivity

ABSTRACT

Background/Case Studies Blood donor based serosurveillance is a convenient and cost-effective strategy to monitor the extent of the COVID-19 pandemic and allows the detection of asymptomatic and recovered cases. The RESPONSE (REDS-IV-P Epidemiology, Surveillance and Preparedness of the Novel SARS-CoV-2 Epidemic) study conducted monthly cross-sectional serosurveys of 1000 routinely obtained donor samples in 6 metropolitan regions (see table). Study Design/Methods: Samples were captured monthly from March or April through June 2020. Siteswere selected based on reports of epidemic activity or as low prevalence control regions. Donations from COVID- 19 convalescent plasma donors were excluded. Coded samples, with routinely collected demographic data and zip code of residence, were tested for SARS-CoV-2 antibodies using the Ortho VITROS anti-SARS-CoV-2 S1 Total Ig (data reported below) with planned confirmation of reactivity on Roche Elecsys® NC Anti-SARS-CoV-2 and a pseudovirus-based neutralization assay. Results/Findings: Table 1 shows donor seroreactivity with 95% CI. For all sites, seroreactivity was <1.0% (range 0.1%-0.9%) at the beginning of the surveillance period. Donor seroreactivity in New York City (NYC) was about 10-fold higher in April through June as compared to March and was much higher than in other locations. There were modest increases in seroreactivity over the study timeframe for all other sites. Conclusions: Modest increases in seroreactivity from baseline were found in all sites, with the largest increase in NYC. SARS-CoV-2 antibody testing of routinely obtained blood donor samples allows for detection of asymptomatic and recovered COVID-19 cases and enables future estimation of infection incidence by geographic and other demographic parameters. This approach will be used in a significantly expanded CDC National serosurveillance study involving all 50 states over 18 months.