SARS-CoV-2 titers in wastewater foreshadow dynamics and clinical presentation of new COVID-19 cases

Abstract

<jats:p>Current estimates of COVID-19 prevalence are largely based on symptomatic, clinically diagnosed cases. The existence of a large number of undiagnosed infections hampers population-wide investigation of viral circulation. Here, we use longitudinal wastewater analysis to track SARS-CoV-2 dynamics in wastewater at a major urban wastewater treatment facility in Massachusetts, between early January and May 2020. SARS-CoV-2 was first detected in wastewater on March 3. Viral titers in wastewater increased exponentially from mid-March to mid-April, after which they began to decline. Viral titers in wastewater correlated with clinically diagnosed new COVID-19 cases, with the trends appearing 4-10 days earlier in wastewater than in clinical data. We inferred viral shedding dynamics by modeling wastewater viral titers as a convolution of back-dated new clinical cases with the viral shedding function of an individual. The inferred viral shedding function showed an early peak, likely before symptom onset and clinical diagnosis, consistent with emerging clinical and experimental evidence. Finally, we found that wastewater viral titers at the neighborhood level correlate better with demographic variables than with population size. This work suggests that longitudinal wastewater analysis can be used to identify trends in disease transmission in advance of clinical case reporting, and may shed light on infection characteristics that are difficult to capture in clinical investigations, such as early viral shedding dynamics.</jats:p>

Surveillance of wastewater revealed peaks of SARS-CoV-2 preceding those of hospitalized patients with COVID-19

“…Few studies have reported longitudinal monitoring of SARS-CoV-2 in wastewater over several months. One study from Massachusetts followed the amount of virus in wastewater between March and May 2020 and could show some fluctuations with an increase of viral genomes until mid-April and thereafter a declining trend ( Wu et al, 2020a ). In this study we found a correlation between the increase in concentrations of viral genomes in wastewater and the number of newly hospitalized patients with COVID-19 with the former preceding the latter by three to four weeks.…”

Monitoring SARS-CoV-2 circulation and diversity through community wastewater sequencing

“…This has led to the recognition of the potential of wastewater-based epidemiology as a valuable tool to assess the spread of the disease at a community level. Recently, the Water Research Institute (KWR) in the Netherlands, as well as others, have demonstrated temporal correlations between SARS-CoV-2 RNA titers in sewage and the number of cases in a particular city or county, where the titers in sewage seem to correlate with the number of reported cases in the population, suggesting a potential role for sewage surveillance as an early warning tool 18,[20][21][22] . Therefore, sewage testing is currently considered globally as an adjunct to patient-based surveillance, and has promise as an early warning indicator of increasing virus circulation.…”

COVID-19 Wastewater Epidemiology: A Model to Estimate Infected Populations

“…4 Both symptomatic and asymptotic individuals shed SARS-CoV-2 in their feces, and studies have demonstrated detection of SARS-CoV-2 genes in raw sewage and primary sewage treatment sludge. [5][6][7][8][9][10][11][12] Before WBE can be widely adapted for COVID-19 prevention and management, a method is needed to estimate the number of active infections from the viral RNA load detected in wastewater. To capture the infection dynamics of COVID-19, we employed a Susceptible-Exposed-Infectious-Recovered (SEIR) model, which has been previously used to predict SARS-CoV-2 transmission.…”