Universal SARS-CoV-2 Testing Among Obstetrical Patients (UNIVERSE-OB) in Ottawa, Canada

ABSTRACT

Objectives: Universal testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within birthing units is an effective strategy to contain infection and estimate community prevalence. Given the high-prevalence of COVID-19 cases in Ontario, the objective of this study was to determine the prevalence of active and recovered SARS-CoV-2 infection among pregnant individuals in Ottawa through universal SARS-CoV-2 and serology testing. Methods: From October 19th to November 27th, 2020, pregnant individuals admitted to triage assessment units at The Ottawa Hospital (TOH) were consented for SARS-CoV-2 testing. Swab and serology samples were analyzed using digital droplet polymerase chain reaction (ddPCR) and enzyme-linked immunosorbent assays, respectively. SARS-CoV-2 seropositivity was defined as a positive result for immunoglobulin (Ig) G, either alone or in combination with IgM and/or IgA. Results: From the 395 enrolled participants, 284 swab and 353 serology samples were collected. We found that 18 of 395 (4.6%) participants had evidence of SARS-CoV-2 exposure 2/284 (0.70%) were positive for SARS-CoV-2 and 16/353 (4.5%) were positive for anti–SARS-CoV-2 IgG. Seropositive participants were similar to seronegative participants in terms of demographics, clinical characteristics, and pregnancy outcomes. Conclusions: The prevalence of SARS-CoV-2 ddPCR positivity and seropositivity in the obstetrical population at TOH was 0.70% and 4.5%, respectively in the fall of 2020. According to local public health data, the infection rate peaked at 0.6% during the study time period. Universal SARS-CoV-2 testing programs may help approximate community prevalence, however, justification of this strategy depends on testing capabilities and the local context of COVID-19 infection. Keywords pregnancy;COVID-19;SARS-CoV-2;universal testing;seroprevalence