Wastewater monitoring finds high COVID-19 levels in Valley

The California Surveillance of Wastewater Systems Network (Cal-SuWers) and the U.S. Centers for Disease Control and Prevention (CDC) National Wastewater Surveillance System (NWSS) announced Tuesday that wastewater testing has found “high” levels of the COVID-19 virus in the San Joaquin Valley.

Wastewater monitoring is a technique used by various health departments to monitor and respond to the spread of infectious diseases. Water samples are taken throughout the day at wastewater treatment plants to combine into a 24-hour sample. The process is then repeated multiple times weekly.

Wastewater monitoring allows water samples to be analyzed in as few as five to seven days after waste enters the sewer, providing fast analysis on the spread of communicable diseases.

Data from the CDC revealed that, compared the week ending July 15, 2023, the state’s wastewater monitoring has detected levels nearly four times higher as of July 13, 2024.

Following the announcement, the Fresno County Department of Public Health (FCDPH) reminded residents that despite vast reductions in hospitalizations and severe cases, COVID-19 still circulates throughout communities and poses a threat to many including older adults and individuals with weakened immune systems.

“COVID-19 vaccines remain one of the most effective tools to reduce the spread of COVID-19 and prevent severe illness,” FCDPH said in a Tuesday press release. “The FCDPH recommends all individuals 6 months and older get vaccinated.”

While wastewater surveillance is effective in determining the presence of COVID-19, the technique did not provide detailed information on the specific strains detected – the California Department of Public Health (CDPH) does identify and track specific variants at a state level using whole genome sequencing.

“As of June 2024, two new subvariants of the Omicron strain, known as FLiRT, have been predicted to be the subvariants with the highest and fastest growing proportion,” the FCDPH said in a statement to The Business Journal.

In addition to tracking COVID-19 infections, wastewater surveillance is also efficient in tracking a variety of bacteria and viruses including influenza and RSV, according to the department.

The department urges residents to contact their primary care physicians, the Fresno County Department of Public Health – Immunization program at (559) 600-3550, or by visiting My Turn to find nearby vaccination sites.

The FCDPH urges high-risk residents to seek testing or treatment.