Number of COVID-19 cases required in a population to detect SARS-CoV-2 RNA in wastewater in the province of Alberta, Canada: Sensitivity assessment

Wastewater-Based Surveillance Is an Effective Tool for Trending COVID-19 Prevalence in Communities: A Study of 10 Major Communities for 17 Months in Alberta

“… 26 We found that the number of new COVID-19 cases per 100000 required to detect SARS-CoV-2 RNA in wastewater at defined probabilities of detection (50%, 80%, and 99%) was higher in smaller communities with <50000 residents than in larger communities with ≥100000 residents. 29 Lethbridge and High River have populations of 100000 and 17000 in their corresponding sewersheds, respectively. A low occurrence of new COVID-19 cases would increase the asymmetry of data between COVID-19 cases and SARS-CoV-2 RNA levels in wastewater, i.e, fewer data points in pairs, likely prompting the relatively low r values.…”

An efficient method to enhance recovery and detection of SARS-CoV-2 RNA in wastewater

“…Several studies have even reported successful detection of SARS-CoV-2 and variants in wastewater up to 14 days prior to clinically reported cases ( Karthikeyan et al, 2022 ; Vo et al, 2022 , Xie et al, 2022 ). Sensitivity analysis showed that the viral RNA could be detected in wastewater at 99% probability if there were higher than 38 new cases (range 17-97) per 100,000 people in the community ( Le, 2023 ; Li et al, 2023 ).…”

Sensitivity of wastewater surveillance: What is the minimum COVID-19 cases required in population for SARS-CoV-2 RNA to be detected in wastewater?

“…Despite the importance and large number of published studies on the detection of SARS-CoV-2 RNA in wastewater, the minimum number of COVID-19 cases required in a population to produce a detectable viral RNA signal in wastewater was largely unknown. Li et al (2023) reported a study in Journal of Environmental Sciences to fill this important knowledge gap.…”

“…To address the fundamental question of the threshold of COVID-19 cases required in a population for SARS-CoV-2 RNA to be detected in wastewater, Li et al (2023) obtained and analyzed a unique and large dataset comprised of high numbers of diagnostic testing for COVID-19 and wastewater analyses spanning the first three waves of COVOD-19 in Alberta, Canada. Wastewater surveillance was initiated two months after the first case of COVID-19 was identified in Alberta.…”

“…The Li et al (2023) study used larger datasets and covered earlier and longer period of the COVID-19 pandemic in comparison with many other studies of RT-qPCR detection of SARS-CoV-2 RNA in wastewater. The datasets also captured the first wave when the numbers of infected individuals in the communities served by WWTPs were small.…”