Traces of omicron found in Southern California sewage, scientists say

This means the next coronavirus outbreak or new variant could be first detected in our wastewater, scientists say.

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Thursday, December 9, 2021
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Scientists are reporting traces of the COVID-19 variant omicron in sewage from multiple cities across the state of California, including in the Bay Area.

SAN FRANCISCO -- Scientists are reporting traces of the COVID-19 variant omicron in sewage from multiple cities across the state of California, including in Southern California.

This means the next coronavirus outbreak or new variant could be first detected in our wastewater.

"Even if a person doesn't even know they are infected, or hasn't gone to get tested in a laboratory, we can detect the signal from the infection in the wastewater. The detection method is very sensitive. We can detect as few as one infection in 100,000 people," said Kara Nelson, a professor of civil and environmental engineering at UC Berkeley.

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For the past 14 months, Dr. Nelson's team at UC Berkeley has been monitoring the genetic material of COVID in wastewater.

They're getting their samples from 15 different sewage facilities across the state. Late last week, they sequenced a sample with traces of the omicron variant.

"We currently monitor at 10 different wastewater locations in the Bay Area and at five sites in the Central Valley and Southern California. At one of the Bay Area sites and one of the Southern California sites, we have detected the potential presence of omicron," said Nelson.

The exact location of the site weren't immediately disclosed.

The Bay Area sample was detected outside of San Francisco, suggesting this process of detection could be faster than clinical samples.

So what is the plan to find other variants?"

"In addition to looking for a specific variant with quantitative PCR, we are also sequencing the wastewater and that allows to look for any mutations that are there even new mutations that we don't know about yet," said Nelson. "It's quite possible that we can detect a new variant in the waste water that hasn't been detected in clinical samples."

The research team, known as the Sewer Coronavirus Alert Network, is working 24/7 measuring daily samples of wastewater.

Their latest findings are also pointing to a detection of omicron in multiple cities.

"We have processed over 60 samples of waste water from the Greater Bay Area. The vast majority of those have been non-detect for omicron. We had not detected it, but in three samples, two from Sacramento and one from Merced, we did detect omicron at very low levels," said Alexandria Boehm, a professor of Stanford's Department of Civil and Environmental Engineering.

Both groups are hoping early detection of variants could help prepare communities to respond before an outbreak.

"What we saw with the delta mutation in wastewater is that it just steadily increased over time, and there was this really strong increase in trend and in its concentration. So we are looking to see if we observe the same thing with the omicron mutation," said Boehm.

Both professors agree there's no risk of COVID in water.

"The virus that causes COVID-19 is very wimpy. It becomes non-infectious very quickly in the wastewater. There is no evidence to indicate that the waste water itself presents a risk for transmission," said Nelson.