Wastewater Monitoring of SARS-CoV-2 in Small Cities Reveals Ongoing COVID-19 Transmission During and After the Pandemic

The SARS-CoV-2 virus, the etiological agent of COVID-19, affected millions of people and caused major public health impacts. With the detection of viral RNA feces of infected individuals, several countries adopted wastewater-based epidemiology to track its circulation. However, most studies focused on large urban centers. This study analyzed the presence and persistence of SARS-CoV-2 in wastewater from two small Brazilian towns with low socioeconomic indices, located in northern Minas Gerais, during and after the pandemic. Wastewater samples were collected biweekly for 12 months from three points in the city of Salinas and one in Rubelita. SARS-CoV-2 RNA was detected at all sampling points via RT-qPCR, with peaks in May, June, October, November 2023, and January 2024, even after the pandemic ended or when no cases were reported. Results were shared with local decision-makers and the public via social media for scientific dissemination. This study highlights wastewater surveillance as an effective COVID-19 monitoring tool, emphasizing its potential to detect and prevent outbreaks in areas with limited testing, providing a valuable public health strategy.