Numerous studies throughout the world are emerging, using sampling of wastewater to predict outbreaks or resurgence of the virus. While labs and testing centers around the country are overwhelmed with demand and challenges with false negatives, government officials are looking for new ways to make decisions about safely reopening their cities and towns. Relying on testing of individuals is often too slow and cost-prohibitive in most places.
Wastewater influent testing has been identified as a “canary in the coal mine” potential early warning system for predicting outbreaks. Similar wastewater epidemiology studies have previously been conducted to track outbreaks of adenovirus, norovirus, rotavirus, and even illicit drug use. In studies using the high sensitivity technique of reverse-transcriptase quantitative PCR, there is the potential to detect a single infected individual among up to 2 million people.
It’s important to note that detection of COVID-19 RNA in wastewater does not imply that the virus is viable and able to infect humans. The World Health Organization (WHO) stated that there is no evidence to date that COVID-19 virus has been transmitted via sewerage systems, with or without wastewater treatment. A panel of wastewater and public health experts determined in August that the occupational risk of COVID-19 infection for wastewater workers is low. More information can be found at here.
A CASE STUDY IN YOSEMITE
In Yosemite National Park, health officials started collecting wastewater samples in June. Although there had been no cases reported from swab testing at the health clinic, the wastewater samples revealed the presence of the virus in the park. The officials from Biobot, the testing company, were able to use the amount of virus detected to estimate that about 170 people were infected in Yosemite Valley.
Source: Paul Chin / The SF Chronicle.
With wastewater testing, detection of the virus can occur up to a week before a person tests positive with nasal swabbing. Testing wastewater also covers the entire population served by the wastewater treatment plant, reducing the burden on overwhelmed labs.
OTHER STUDIES USING WASTEWATER TO TRACK CORONAVIRUS
San Francicso Bay Area: Ali Boehm, Ph.D., a professor of civil and environmental engineering at Stanford University has been studying the virus in wastewater since February 2020. Her team at Stanford is analyzing wastewater samples from about 50 utilities, including many in the Bay Area. These agencies are hoping to get a better grasp on the spread of the virus in their backyards to guide response measures.
Netherlands: In five cities in the Netherlands, a clear increase in reported cases coincided with an increase in concentration of the virus in wastewater.
Syracuse University, NY: Scientists will test dormitory wastewater twice a week to try to detect early warning signs of an outbreak.
Utah: As of June 11, 2020, Utah public health officials had completed six-week trial of screening wastewater for the coronavirus and plan to scale up the program to sample at 40 additional treatment plants.
Source: The National Academies of Science, Engineering, Medicine.
For Further Information
Yosemite Park Article / The SF Chronicle
Wastewater Epidemiology for COVID-19 Monitoring