Development of wastewater pooled surveillance of SARS-CoV-2 from congregate living settings

Abstract

Wastewater-based monitoring for SARS-CoV-2 holds promise as tool to inform public health-decision making. Testing at individual building-level could be an efficient, passive means of preventing early detection of new cases in congregate living settings, but this approach has not been validated. Sample collection protocols were developed and refined during preliminary sampling from a hospital and a local municipal wastewater treatment plant. Molecular diagnostic methods were compared side-by-side to assess feasibility, performance and sensitivity. Optimized sample collection and processing protocols were then used to monitor two occupied dormitory complexes (n=105 and 66) over eight weeks. Wastewater results were validated using known case counts from external clinical testing of building occupants. Results confirm that ultracentrifugation from a 24 hour composite collection had a sensitivity of 95% and a specificity of 100%. However, if the detection of convalescent shedding is considered a false positive then the sensitivity would be 95.2% but the specificity would drop to 52%. We determined a highly sensitive method for detecting SARS-CoV-2 shedding in building wastewater however our methods could not distinguish new infectious cases from persistent convalescent shedding of SARS-CoV-2 RNA. Future work must focus on methods to distinguish new infections from convalescent shedding to widely deploy this promising wastewater surveillance tool.

High frequency, high throughput quantification of SARS-CoV-2 RNA in wastewater settled solids at eight publicly owned treatment works in Northern California shows strong association with COVID-19 incidence

“…Numerous independent COVID-19 WBE efforts have covered monitoring at a range of scales, from the building level to country-wide implementation 7,9,10 . The methods employed have also varied, with the vast majority focusing on the liquid fraction of municipal wastewater.…”

Evaluating recovery, cost, and throughput of different concentration methods for SARS-CoV-2 wastewater-based epidemiology

“…Importantly, it does not require individuals to opt-in, thereby capturing both symptomatic and asymptomatic individuals. The potential of WBE to inform public health measures by offering trend tracking and prevalence estimates is already of growing interest to local governments and has been put to use by universities to proactively prevent COVID-19 outbreaks in campus housing (Colosi et al, 2020; Stadler et al, 2020).…”

Averting an outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in a university residence hall through wastewater surveillance

“…Students who are deemed no longer infectious, but still classified as convalescing, are normally approved to return to their assigned accommodations. Convalescent shedding of SARS-CoV-2 can persist for weeks to months, thus universities planning to use WBE need to consider this as part of their quarantine plans (Colosi et al, 2021).…”

“…Indeed, to yield most benefit, strategic sampling within a sewershed targeting neighbourhoods, schools or congregate living facilities provides finer spatial resolution that can result in actionable public health responses to limit or halt COVID-19 transmission (Hassard et al, 2021). Amongst early adopters of this approach have been colleges and universities throughout North America, many of whom are using WBE to monitor residence halls for early evidence of COVID-19 infection as an integral component of campus screening programs Barich and Slonczewski, 2021;Betancourt et al, 2021;Colosi et al, 2021;Gibas et al, 2021;Harris-Lovett et al, 2021;Karthikeyan et al, 2021;Reeves et al, 2021;Scott et al, 2021;Travis et al, 2021). In fact, by the completion of the 2020-21 academic year, >200 postsecondary institutions in North America, and >250 worldwide were involved in some form of wastewater surveillance on campus (Naughton et al, 2021 monitoring triggered a public-health response that may have averted an actual outbreak (Betancourt et al, 2021;Gibas et al, 2021).…”