Watch hereInfections of SARS-CoV-2, the causative virus of COVID-19, go undetected in a large percentage of the population because many people are asymptomatic or experience only mild symptoms. Undiagnosed, infected individuals are contagious and play a role in the rapid transmission of the virus. Confirmed clinical cases of COVID-19 are a significant underestimate of the total number of SARS-CoV-2 infections, particularly in areas with limited testing capabilities. Fecal viral shedding presents the opportunity to use wastewater-based epidemiology (WBE) to monitor and track the spread of SARS-CoV-2 infection by testing for the virus in wastewater. Infections can be monitored using wastewater samples because they reflect a pooled urine and fecal sample of an entire community. Wastewater monitoring is an additional tool to monitor COVID-19 infection dynamics at a community scale to inform the allocation of healthcare resources and social distancing policies.
Houston Water treats an average of 250 million gallons of wastewater per day, and services over 2.1 million people at 39 wastewater treatment plants. In collaboration with Houston Health Department, Houston Water, and Baylor College of Medicine, we have been collecting, processing, and analyzing weekly untreated wastewater samples from all 39 wastewater treatment plants in Houston. SARS-CoV-2 has been detected in wastewater samples from every wastewater treatment plant. Our data suggests that vial loads of SARS-CoV-2 in wastewater lead nasal positivity rates by one- to two-weeks in Houston. Viral load data generated each week is used to identify geographic areas that are experiencing high infection burdens and areas that may be experiencing an outbreak (sharp increases in viral loads week over week). The Houston Health Department COVID-19 team uses the wastewater viral detection trends produced to deploy strike teams (testing units and contact tracers) to areas where an outbreak is expected. This talk will summarize the methods being using to measure SARS-CoV-2 in wastewater samples, the statistical models developed by our team to analyze wastewater data, and how the data is being used by the Houston Health Department.
