Universal SARS-CoV-2 testing on admission to the labor and delivery unit: Low prevalence among asymptomatic obstetric patients

Prior to this intervention, multiple infection control strategies in addition to those routine in our facilities had been implemented in response to the COVID-19 pandemic: (1) symptom and exposure screening of all patients with implementation of immediate isolation if symptom screen is positive and testing for SARS-Cov-2, (2) universal masking of employees, patients, and visitors on facility premises,3 (3) daily employee symptom attestation with exclusion from work and referral for testing if symptom screen positive; and (4) deferral of all nonessential in-person visits and elective procedures. Among asymptomatic women, 9 of 618 (1.5%) tested positive (Fig. 1). [...]9 of 20 patients positive for SARS-CoV-2 at admission (45%) had no symptoms of COVID-19 at presentation. Notably, the 1%–2% incidence of asymptomatic infection in our population more closely mirrors asymptomatic infection rates in other areas.4,5 Several theories may explain the lower prevalence of asymptomatic infection in Boston compared to New York City: (1) we began testing >30 days after physical distancing orders were placed by the state and hence were sampling at a time with declining community transmission, (2) the overall population density of greater Boston is lower than New York City, perhaps leading to less community-based transmission, and (3) some New York hospitals transiently stopped or considered stopping birth partners from attending deliveries, which could have led to some women underreporting symptoms.