Public Health Interventions Guided by Houston's Wastewater Surveillance Program During the COVID-19 Pandemic

Abstract

Since the start of the COVID-19 pandemic, wastewater surveillance has emerged as a powerful tool used by public health authorities to track SARS-CoV-2 infections in communities. In May 2020, the Houston Health Department began working with a coalition of municipal and academic partners to develop a wastewater monitoring and reporting system for the city of Houston, Texas. Data collected from the system are integrated with other COVID-19 surveillance data and communicated through different channels to local authorities and the general public. This information is used to shape policies and inform actions to mitigate and prevent the spread of COVID-19 at municipal, institutional, and individual levels. Based on the success of this monitoring and reporting system to drive public health protection efforts, the wastewater surveillance program is likely to become a standard part of the public health toolkit for responding to infectious diseases and, potentially, other disease-causing outbreaks.

Keywords: COVID-19; SARS-CoV-2; public health interventions; wastewater; wastewater surveillance.

Figure 1.

SARS-CoV-2 wastewater monitoring dashboard in Houston, Texas, 2022. The main page displays a map of Houston and the surrounding area with the coverage area of the 39 wastewater treatment plants (WWTPs) and the point location of schools. The dashboard is interactive. Data update as the user selects locations or scrolls through time. The menu button leads to other parts of the dashboard, including heat maps of viral load levels and trends, detection of influenza in schools, detection of SARS-CoV-2 variants, and a zip code map of estimated viral load. The map illustrates the benefits of geospatial analysis: the trend in northwest WWTPs is decreasing (indicated by down arrows), while trends in other WWTPs are increasing (indicated by up arrows) or have plateaued (indicated by dashes).

Figure 2.

Use of SARS-CoV-2 wastewater monitoring dashboard, Houston, Texas, October 1, 2021, through June 10, 2022. The daily number of clicks on the dashboard is plotted alongside the City of Houston’s daily polymerase chain reaction (PCR)–positive case count, PCR-negative case count, and 14-day moving average PCR positivity rate. The daily number of dashboard clicks over time increases as the 14-day moving average PCR positivity rate increases, even if testing counts do not increase. This is seen in the Omicron wave of December 2021–February 2022 and again in May–June 2022.