Performance of an extended triage questionnaire to detect suspected cases of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in obstetric patients: Experience from two large teaching hospitals in Lombardy, Northern Italy

Objectives: 1. To assess the performance of an extended questionnaire in identifying cases of SARS-CoV-2 infection among obstetric patients. 2. To evaluate the rate of infection among healthcare workers involved in women’s care. Study design: A prospective cohort study of obstetric patients admitted to MBBM Foundation and Buzzi Hospital (Lombardy, Northern Italy) from March 16th to May 22nd, 2020. Women were screened on admission by a questionnaire investigating major and minor symptoms of infection and high-risk contacts in the last 14 days. SARS-CoV-2 assessment was performed by RT-PCR on nasopharyngeal swabs. Till April 7th, a targeted SARS-CoV-2 testing triggered by a positive questionnaire was used; from April 8th, a universal testing approach was implemented. Results: There were 1,177 women screened by the questionnaire, which yielded a positive result in 130 (11.0%) cases. SARS-CoV-2 RT-PCR was performed in 865 (73.5%) patients, identifying 51 (5.9%) infections. During the first period, there were 29 infected mothers, 4 (13.8%) of whom had a negative questionnaire. After universal testing implementation, there were 22 (3%, 95% CI 1.94% - 4.04%) infected mothers, 13 (59.1%) of whom had a negative questionnaire; rate of infection among asymptomatic women was 1.9%. Six of the 17 SARS-CoV-2-positive women with a negative questionnaire reported symptoms more than 14 but within 30 days before admission. Isolated olfactory or taste disorders were identified in 15.7% of infected patients. Rate of infection among healthcare workers was 5.8%. Conclusions: An exhaustive triage questionnaire can effectively discriminate women at low risk of SARS-CoV-2 infection in the context of a targeted and a universal viral testing approach. In 15.7% of infected women, correct classification as a suspected case of infection was due to investigation of olfactory and taste disorders. Extension of the assessed time-frame to 30 days may be worth considering to increase the questionnaire’s performance.