Background: The persisting Coronavirus disease 2019 (COVID-19) pandemic and limited vaccine supply has led to a shift in global health priorities to expand vaccine coverage Relying on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) molecular testing alone cannot reveal the infection proportion, which could play a critical role in vaccination prioritization We evaluated the utility of a combination orthogonal serological testing (COST) algorithm alongside RT-PCR to quantify prevalence with the aim of identifying candidate patient clusters to receive single and/or delayed vaccination Methods: We utilized 108,505 patients with suspected COVID-19 in a retrospective analysis of SARS-CoV-2 RT-PCR vs IgG-nucleocapsid (IgGNC) antibody testing coverage in routine practice for the estimation of prevalence Prospectively, an independent cohort of 21,388 subjects was simultaneously tested by SARS-CoV-2 RT-PCR and IgGNC to determine the prevalence We used 614 prospective study subjects to assess the utility of COST (IgGNC, IgM-spike (IgMSP), and IgG-spike (IgGSP)) in establishing the infection proportion to identify a single-dose vaccination cohort Results: Retrospectively, we observed a 6 3% (6871/108,505) positivity for SARS-CoV-2 RT-PCR, and only 2 3% (2533/108,505) of cases had paired IgGNC serology performed Prospectively, IgGNC serology identified twice the number of COVID-positive cases in relation to RT-PCR alone COST further increased the number of detected positive cases: IgGNC+ or IgMSP+ (18 0%);IgGNC+ or IgGSP+ (23 5%);IgMSP+ or IgGSP+ (23 8%);and IgGNC+ or IgMSP+ or IgGSP+ (141/584 = 24 1%) Conclusion: COST may be an effective tool for the evaluation of infection proportion and thus could define a cohort for a single dose and/or delayed vaccination
Expanding COVID-19 Vaccine Availability: Role for Combined Orthogonal Serology Testing (COST)