Wastewater as an indicator of COVID-19

monitoring of mass gatherings in a city of Legal Amazon on the North of Brazil

Abstract

One of the biggest challenges on health surveillance during COVID-19 pandemic was surveillance and detection of new cases of infection with the objective of stopping fast disease propagation. Mass gatherings are receiving attention from public authorities, considering their roles in circulating COVID-19 virus on an extensive contingent of people. Considering the limitation for mass laboratory tests, high rates of sub-notification and asymptomatic infections, some complementary surveillance strategies were implemented in many countries, such as sewage epidemiological surveillance. This study aimed to detect the presence of SARS-CoV-2 on sewage of the Araguaína-TO, Brazil, community during a mass gathering; a traditional agricultural exposition that gathered many people in a few weeks. Quantification of SARS-Cov-2 through sewage was performed by RT-qPCR and the detected viral loads were normalized using the population served by the studied sewage points. Data generated were compared to the city’s epidemiological data of clinical and laboratory trials of COVID-19 displaying a sub-notification of infections. Amidst vaccination progression, reduction of symptomatic infections and return of events, sewage monitoring presented itself as a fast alert system, exposing virus circulation in the city before and after an increase in case notifications. Results demonstrated a tool to aid surveillance, indirectly testing hundreds of people through a single sample, therefore, enhancing the health system to give assistance to new cases.

Keywords: SARS-CoV-2; Environmental surveillance; Sewage-based epidemiology; People gathering.