The COVID-19 pandemic marks its 2nd anniversary this month, and weirdly, it alternatively feels to us like that day was either forever ago or just yesterday. As graduate students, one thing is for sure: the pandemic permanently transformed the way we work and live our lives. As it is also World Water Day today, we would like to share our knowledge and impressions related to this, the first (though, likely not the last) pandemic of the 21st century. As water professionals, our role in understanding and mitigating the risks associated with pandemics is more extensive than you might suspect.
Preventative measures play a vital role in managing a pandemic: washing hands, social distancing, using masks, adequate ventilation of indoor spaces, vaccination (when available) all help keep us healthy. When the strain on hospitals gets too heavy, quarantines help keep cases low and healthcare workers safe. Throughout it all, public health authorities rely on data to issue proper guidance. The most critical metrics they use are case counts obtained via clinical testing and the number of hospital admissions. However, in recent months, many countries have stopped mass diagnostic campaigns, cutting off their primary data source for assessing the spread of the disease in the population.
Thankfully, there is another method to monitor outbreaks that YWPs should be aware of: Wastewater-based epidemiology (WBE) consists of taking viral measurements in a community’s wastewater to track the spread of the disease. Not everyone can get tested these days, but luckily, most people still use toilets! Infected people excrete fragments of the SARS-CoV-2 virus in their feces, even if the infection is too recent to show symptoms or because someone is an asymptomatic carrier. WBE, therefore, is an excellent tool for collecting near real-time measures of community-level incidence and prevalence of SARS-CoV-2(Abdeldayem et al., 2022; McMahan et al., 2021; O’Keeffe, 2021; Xiao et al., 2022). Not only that, but it is also cost-effective since it only takes one sample to gauge the spread of the disease in an entire sewershed. Though this method isn’t new – it has been used before to track polio cases in low-resource areas, as well as drug use and exposure to pesticides in industrialized countries – WBE had never been deployed to the extent that it has for the COVID-19 pandemic in history.
Many monitoring and research studies started immediately upon the declaration of the pandemic in different countries. Over 200 universities, 2300 sampling sites, and 55 countries, including Canada, have not only collected WBE surveillance data for SARS-CoV-2, but they also released that data publicly through over 59 online dashboards that show the ebb and flow of outbreaks throughout the pandemic as waves of viral RNA in wastewater. This unprecedented monitoring effort allows jurisdictions worldwide to assess the situation in their communities and allocate resources to better deal with the challenges of the day, whether it be recruiting more contact tracers or securing more hospital beds (Control & Prevention, 2021; Sims & Kasprzyk-Hordern, 2020). Across Canada, wastewater testing for SARS-CoV-2 RNA has been performed in over 20 cities, many of which used this data to guide their decisions (O’Keeffe, 2021).
In Québec City, where we live and work, WBE surveillance has also occurred throughout 2021, spearheaded by our research group. Thanks to wastewater monitoring, public health authorities have detected possible outbreaks among at-risk populations, such as people frequenting homeless shelters or elders living in long-term care facilities. Equipped with wastewater measurements, public health authorities could make time-sensitive decisions, such as launching mass testing or vaccination campaigns, even before anyone had reported symptoms, keeping vulnerable members of our community safe. It is easy to feel overwhelmed and helpless when faced with a situation as all-encompassing as a worldwide pandemic. Still, WBE has created a way for water professionals to provide expertise and support to the global fight against the disease. Though that can make us feel empowered, it also comes with a burden of responsibility.
Managing the pandemic requires high-quality data, of course, and as you all know, wastewater is messy, and the data coming out of it often is, too. The complexity of the wastewater matrix, dilution of domestic sewage by rain and industrial effluents, the presence of inhibitory compounds and the decay of RNA inside the sewer network conspire to make WBE measurements challenging to collect and even trickier to interpret (Kumblathan, Piroddi, Hrudey, & Li, 2022). As governments and public health agencies begin to take over WBE monitoring from research institutions, research is still dearly needed to improve assay methods, data management and modelling to tackle the challenges presented by WBE. Canadian labs already contribute to this global effort with the development of an open data format to share WBE data and by conducting inter-laboratory studies that help standardize analytical methods. A recent example of the latter demonstrates the consistency of results within the participating laboratories for detecting SARS-CoV-2 variants in wastewater samples (Chik et al., 2021; Kumblathan et al., 2022).
Beyond pandemic surveillance, it is also critical for the water sector to adapt to the effects of the pandemic itself: we definitely can’t afford wastewater treatment plants taking sick days! New resources and approaches need to be adopted to handle emergencies in the wastewater treatment facilities for continuous operation, emergency responses, resiliency, and mitigation during the pandemic (Rahman et al., 2021).
Gamze KIRIM1,2, Jean-David THERRIEN1,2
1 modelEAU, Université Laval, 1065 avenue de la Médecine, Québec G1V 0A6, QC, Canada,
2 CentrEau, Quebec Water Research Centre, 1065 avenue de la Médecine, Québec G1V 0A6, QC, Canada
Abdeldayem, O. M., Dabbish, A. M., Habashy, M. M., Mostafa, M. K., Elhefnawy, M., Amin, L., Al-Sakkari, E. G., Ragab, A., Rene, E. R. (2022). Viral outbreaks detection and surveillance using wastewater-based epidemiology, viral air sampling, and machine learning techniques: A comprehensive review and outlook. Science of The Total Environment, 803, 149834.
Chik, A. H., Glier, M. B., Servos, M., Mangat, C. S., Pang, X.-L., Qiu, Y., D’Aoust, P. M., Burnet, J.-B., Delatolla, R., Dorner, S. (2021). Comparison of approaches to quantify SARS-CoV-2 in wastewater using RT-qPCR: Results and implications from a collaborative inter-laboratory study in Canada. journal of environmental sciences, 107, 218-229.
Control, C. f. D., & Prevention. (2021). National wastewater surveillance system (NWSS). Centers for Disease Control and Prevention. https://www. cdc. gov/coronavirus/2019-ncov/cases-updates/wastewater-surveillance. html.
Kumblathan, T., Piroddi, N., Hrudey, S., & Li, X. (2022). Wastewater Based Surveillance of SARS-CoV-2: Challenges and Perspective from a Canadian Inter-laboratory Study. Journal of Environmental Sciences (China).
McMahan, C. S., Self, S., Rennert, L., Kalbaugh, C., Kriebel, D., Graves, D., Deaver, J.A., Popat, S.C.Karanfil, T. (2021). COVID-19 wastewater epidemiology: a model to estimate infected populations. The Lancet Planetary Health, 5(12), e874-e881.
O’Keeffe, J. (2021). Wastewater-based epidemiology: current uses and future opportunities as a public health surveillance tool. Environmental Health Review, 64(3), 44-52.
Rahman, A., Belia, E., Kirim, G., Hasan, M., Borzooei, S., Santoro, D., & Johnson, B. (2021). Digital solutions for continued operation of WRRFs during pandemics and other interruptions. Water Environment Research, 93(11), 2527-2536.
Sims, N., & Kasprzyk-Hordern, B. (2020). Future perspectives of wastewater-based epidemiology: monitoring infectious disease spread and resistance to the community level. Environment international, 139, 105689.
Xiao, A., Wu, F., Bushman, M., Zhang, J., Imakaev, M., Chai, Duvallet, C., Endo, N., Erickson, T. B., Armas, F. (2022). Metrics to relate COVID-19 wastewater data to clinical testing dynamics. Water research, 118070.