How has the COVID-19 pandemic impacted wastewater-based epidemiology?

Wastewater-based epidemiology (WBE) was one of the areas of scientific knowledge that developed significantly with the COVID-19 pandemic, with robust worldwide application to monitor the circulation of the SARS-CoV-2 virus in urban communities at different scales and levels. This mini-review assesses how the COVID-19 pandemic may have influenced the WBE based on the investigation of 1305 scientific reports published (research, review, and conference papers) up to the end of 2022, considering the research objects, funding sources, actors, and countries involved. As a result, 71 % of all WBE-based publications occurred since the beginning of the pandemic, with 62 % addressing SARS-CoV-2, demonstrating the migration of WBE's relative importance in studies on drug abuse, pharmaceuticals consumption, and other disease-causing organisms to the constitution of a tool to support the monitoring of the coronavirus. Before the pandemic, WBE was a tool used for epidemiological surveillance of several diseases (54 % of studies), drug abuse (30 %), and pharmaceutical consumption (9 %). With the pandemic, these research topics lost to space, constituting only 37 % of the area's studies, and SARS-CoV-2 became the central object of studies. In addition, there has been a 4.7 % expansion of developing country participation in sewage surveillance publications and greater diversification of collaborators and funders, especially from government, businesses, and the water industry. International research partnerships had a reduction of 8 %, consequently, there was an increase in local and regional partnerships. With the COVID-19 pandemic, funding for research in WBE became approximately 6.5 % less dependent on traditional research funds. The future of WBE involves different approaches, including different focuses of research and technological advancements to improve the sensitivity, precision, and applicability of these investigations. The new WBE research arrangements are promising, although the post-pandemic challenges are likely to be in maintaining them and overcoming the trend toward a lack of diversity in study subjects.

20-Month monitoring of SARS-CoV-2 in wastewater of Curitiba, in Southern Brazil.

The COVID-19 pandemic resulted in the collapse of healthcare systems and led to the development and application of several approaches of wastewater-based epidemiology to monitor infected populations. The main objective of this study was to carry out a SARS-CoV-2 wastewater based surveillance in Curitiba, Southern Brazil Sewage samples were collected weekly for 20 months at the entrance of five treatment plants representing the entire city and quantified by qPCR using the N1 marker. The viral loads were correlated with epidemiological data. The correlation by sampling points showed that the relationship between the viral loads and the number of reported cases was best described by a cross-correlation function, indicating a lag between 7 and 14 days amidst the variables, whereas the data for the entire city presented a higher correlation (0.84) with the number of positive tests at lag 0 (sampling day). The results also suggest that the Omicron VOC resulted in higher titers than the Delta VOC. Overall, our results showed that the approach used was robust as an early warning system, even with the use of different epidemiological indicators or changes in the virus variants in circulation. Therefore, it can contribute to public decision-makers and health interventions, especially in vulnerable and low-income regions with limited clinical testing capacity. Looking toward the future, this approach will contribute to a new look at environmental sanitation and should even induce an increase in sewage coverage rates in emerging countries.