SLO County uses wastewater samples to monitor COVID trends
Pandemic lockdowns may now be a thing of the past, but local public health officials are still keeping an eye on COVID-19 numbers. One way they do that is by analyzing wastewater samples.
Wastewater sampling has been used nationally since the 1970s as a way to identify levels of infection within communities. Now, it’s widely used to detect the virus of COVID-19, including here on the Central Coast.
San Luis Obispo County epidemiologist Jessie Burmester said samples are collected from multiple wastewater treatment sites around the county then sent to an off-site lab for testing.
“It’s when an asymptomatic or symptomatic individual uses the toilet, a shower or sink or anything that leads to a wastewater facility or sewage system and from there samples can get pulled,” she said.
Wastewater monitoring has some limitations. For example, detection of the virus means it’s present but does not indicate the severity of disease or how many people are infected, so Burmester said the data is mainly used to identify trends. She said they combine that with testing and hospitalization numbers to get a more complete picture of what’s happening in the community.
“Detection of SARS-CoV-2, the virus that causes COVID-19, is either going up, going down or kind of plateauing and staying the same,” she said.
How long SLO County will continue to monitor wastewater for the virus is unknown, but they are doing it now. Burmester said the numbers bounced around a bit this summer.
“Wastewater data in July was kind of noisy, so we were seeing some sites increase, others were decreasing, so there wasn’t a lot of consistency, but as we headed into the month of August, we definitely began to see that consistency among all of our sites where they were having increased detection of SARS-CoV-2,” she said.
Burmester said there was consistently higher wastewater detection in the month of August, but the levels are changing again, and she’s hoping for a downward trend.
“In the last two weeks, we’ve actually seen a decline in a lot of our wastewater sites or a plateau,” she said.
Burmester said COVID-19 continues to exist and should be treated like other diseases that circulate periodically in the community. She said to stay home if you’re sick, and get vaccinated when you can.
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