Implementation of an epidemiological surveillance strategy for COVID-19 focused on groups at high risk of SARS-CoV-2 infection

ESANDI MARÍA DEL CARMEN; MARINOVICH JOEL; BERGÉ IGNACIO; GARCÍA NICOLÁS; GERMÁN LORENA; AYALA PEÑA VICTORIA; SIERRA FERMIN; SERRALUNGA GABRIELA; ESANDI MARÍA EUGENIA; DEL VALLE MARTA; BOUZAT CECILIA

Congreso; LXVI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2021

SAIC

The COVID-19 pandemic has been a challenge to implement strategies to mitigate thetransmission of the SARS-CoV-2 virus. Asymptomatic transmission among healthcare workers(HCWs) at the front line of care is particularly concerning due to the potential emergence ofoutbreaks at healthcare centers. With the final goal of early identification and isolation ofasymptomatic infected HCWs, we validated a pooled-sample screening and assessedimplementation outcomes and results of an epidemiological surveillance strategy carried outduring a 12-month period at public health institutions in Bahía Blanca. To develop and validate acoronavirus detection method, RNA was extracted from nasopharyngeal swabs and identificationof the viral E gene was done by an “in-house” RT-qPCR using Taqman probes and the human geneRNAseP as a control. Validation against a commercial kit demonstrated high sensibility andspecificity of our test (95%, IC 95%: [85%-100%]). To increase our testing capacity, we validatedsample pooling (n= 5) prior to RNA extraction. The results showed a sensibility of 73% (IC 95%:[46%-99%]) and specificity of 100% against individuals. A tailor-made software called “VIGI-COVID”was designed to properly manage data. A prospective cohort study was conducted since 15/09/20to 15/09/21. 860 HCWs were included in the epidemiological surveillance and 1765 swabs wereperformed. The annual cumulative incidence was 2,30% IC95% [1,26% - 3,39%] (20/860), and 43%of the 860 HCWs were swabbed more than once. Our study demonstrated the utility ofcomprehensive screening of asymptomatic HCWs during the COVID19 pandemic. Earlyidentification and isolation of infected HCWs prevent the onward transmission of SARS-CoV-2,reducing the risk of healthcare-associated outbreaks.