As the new dominant covid variant called BQ, one emerges, scientists
are looking beyond traditional methods to track it spread the newest
tool in their arsenal. Wastewater. Special correspondent Cat Wise
traveled to California, one of the first states to test wastewater
for Covid.
Every day more than 100 million gallons of wastewater flows into
this treatment facility in Santa Clara County, California It's the
largest in the San Francisco Bay area, serving more than one million
residents in Silicon Valley.
Sewage spewing out from these tanks is something most people want
to avoid.
Extract the RNA from the wastewater. But Stanford University environmental
and civil engineering professor Alexandria Behm sees a public health
goldmine. Can we look at all the
Together.
In March of 2020. Just weeks after one of the first coronavirus cases
in the country was confirmed here in Santa Clara County
and her colleagues began testing wastewater samples. We found that
we could detect Sarah's Cove a to R n a in wastewater, and then we
found that we could measure its concentration and see how it could
change over time and how that matched
With data from reported cases. I was running with my cell phone,
and I got in the first set of results, and I could see right then
and there that the changes in concentration where similar to what
was happening with the cases and I was like, Oh, my gosh, I can't
believe this is going to work.
Using wastewater to monitor viruses is not new. For decades, scientists
around the world have used wastewater to track polio outbreaks.
But it had never been used to track a respiratory disease. People
infected with Covid can shed the virus in their waste days or weeks
before they may have symptoms, which bombs says can provide an early
warning for public health officials. Wastewater surveillance is
Um, just it could be like a complete revolution in the way that we
track infectious disease and communities. And the uptake of this
like technology is really unprecedented. We've gone from 0 to 100
in like two years. In November of 2020. She and her colleagues launched
a program to track covid at eight Northern California treatment plants.
It is now expanded to 70 sites and as part of the CDC zone Wastewater
surveillance system, which generates data for more than 1000 sites,
make sure everything runs smoothly. San Jose Santa Clara Wastewater
facility operator Justin Sabila took us to an underground area where
he and his colleagues take samples of semi solid waste known as sludge
Every four hours. We usually try to get about 250 million liters.
Of sample.
Roughly
The samples are sent to a lab where they tested not only for Covid
but also influenza, respiratory, Sensational virus, or RSV and monkey
pox, known as M parks in California.
The results are sent to public health officials around the country,
including Dr Sara Cody, the head of Santa Clara's Public Health department.
What you really need to do is look at where are we, now in the wastewater
now has more than two years worth of data showing how closely covid
cases in her county correlated with virus levels in the wastewater,
Then this summer, Cody says. Fewer people were tested at clinics
and hospitals, but wastewater concentrations stayed high.
When I see this, I see why. Why? Over time we've had growing confidence.
That the wastewater is the truth. Um, and now we can certainly see
that the waste water levels are still elevated, and we trust that
we know the wastewater doesn't lie.
Cody says she now regularly relies on Stanford's data to make public
health decisions like recommending that residents continue to mask
indoors in public places. One downside to wastewater. Monitoring,
however, is time and money. But officials here say it only costs
about $100 every time a diseases tested that can vary elsewhere,
depending on location and population being tested.
If you take one sample of wastewater, you can get information about
in San Jose 1.5 million people or even at a small plant 10,000 people
multiply the cost of the wastewater tests by the number of people,
So in that sense, wastewater is not cost prohibitive. It is actually
really cheap and economical.
Still, there are concerns some communities will be left out as wastewater
testing expands the rural town of S. Pardo where nearly 50% of residents
are Latino.
Is now part of a program sampling treatment facilities across California's
Central Valley. Like many communities in the area, it was hit hard
by the pandemic, but didn't have access to wastewater testing early
on to track the spread.
This is something that becomes really important if we have wastewater
monitoring data to make that available for the public. Shell is a
civil and environmental engineer at UC Davis and one of the lead
researchers in the program, she says it's important wastewater testing
captures data for underserved communities. What we wanted to do was
help fill that data gap and really try to focus on increasing health
equity by increasing access to data across all of our communities
and
Really rural areas.
Agricultural areas and disadvantaged communities downgrade to our
medium levels. Remy Sison is YOLO counties public health officer.
She says wastewater surveillance can be especially helpful for tracking
disease and communities that may have limited access to testing.
Now we have this additional tool in our toolbox to be able to look
at what's happening in the entire community instead of relying on
the people who are able to get tested, But I can't make any individual
level decisions. I can't say. You know it was this household this
household that household and so that's a piece that we can tease
out in terms of who needs to get treatment who needs to isolate?
Back at Stanford bomb hopes wastewater testing will continue to expand
around the country.
I know and California that wastewater surveillance is probably here
to stay, and I hope that there is enough funding through the state
government and through the federal government to really make this
part of our infrastructure for health monitoring in the United States
infrastructure, she says. That could one day help prepare us for
the next pandemic.