RESUMEN
The coronavirus disease 2019 (COVID-19) pandemic has disproportionately affected seniors living in congregate living settings. The evolving surveillance context has led to novel use of wastewater surveillance to monitor levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in these settings. This study presents a pilot of upstream congregate living wastewater surveillance of SARS-CoV-2 for the detection of COVID-19 outbreaks and the effects of early public health interventions. We monitored localized wastewater SARS-CoV-2 levels from four congregate living settings March 15, 2021 to October 1, 2022 and correlated these levels with suspected and confirmed COVID-19 outbreaks determined by other methods. We identified five wastewater signals that correlated with confirmed outbreaks and three wastewater signals that did not correlate with subsequent outbreaks. In the five confirmed outbreaks, the wastewater signal was detected 2-10 days (median, five days) prior to confirmation of the outbreak by case testing. This pilot demonstrates upstream sampling for SARS-CoV-2 in wastewater may effectively detect outbreaks prior to their detection through symptomatic case testing and could support a balanced approach to outbreak response in congregate living settings, leading to increased wellbeing of these residents.
RESUMEN
Background: The ongoing coronavirus disease 2019 (COVID-19) pandemic has necessitated novel testing strategies, including the use of rapid antigen tests (RATs). The widespread distribution of RATs to the public prompted Peterborough Public Health to launch a pilot RAT self-report tool to assess its utility in COVID-19 surveillance. The objective of this study is to investigate the utility of RAT using correlations between RAT self-report results and other indicators of COVID-19. Methods: We investigated the association between RAT results, PCR test results and wastewater levels of nmN1N2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genes (to infer COVID-19 levels) using Pearson's correlation coefficient. Percent positivity and count of positive tests for RATs and polymerase chain reaction (PCR) tests were analyzed. Results: The PCR percent positivity and wastewater were weakly correlated (r=0.33, p=0.022), as were RAT percent positivity and wastewater nmN1N2 levels (r=0.33, p=0.002). The RAT percent positivity and PCR percent positivity were not significantly correlated (r=-0.035, p=0.75). Count of positive RATs and count of positive PCR tests were moderately correlated (r=0.59, p<0.001). Wastewater nmN1N2 levels were not significantly correlated with either count of positive RATs (r=0.019, p=0.864) or count of positive PCR tests (r=0.004, p=0.971). Conclusion: Our results support the use of RAT self-reporting as a low-cost simple adjunctive COVID-19 surveillance tool, and suggest that its utility is greatest when considering an absolute count of positive RATs rather than percent positivity due to reporting bias towards positive tests. These results can help inform COVID-19 surveillance strategies of local public health units and encourage the use of a RAT self-report tool.
