UCSD reports 'unprecedented' spike in wastewater COVID viral load
Speaker 1: (00:00)
Researchers at UC San Diego say that a COVID surge this winter is not just a possibility it's already here and they're basing their projection on the amount of virus detected in the county's wastewater. Researchers have been monitoring the viral levels in wastewater for months now, and they say the amount detected this weekend is the highest. Since last February preliminary molecular testing indicates the wastewater contains both the Delta and Omicron variants. Joining me is San Diego union Tribune, biotech reporter Jonathan Wilsonn. Jonathan. Welcome. Good to be with you from your report. It sounds like the amount of virus discovered was shocking to the researchers. Is that a fair statement?
Speaker 2: (00:45)
It is a fair statement that it might actually be an understatement though, to be honest. So this announcement from UC San Diego came out at around 10:40 AM on a Saturday. Uh, you know, universities usually don't make weekend announcements, but the language in there was pretty clear and pretty concerning the university called the amount of virus that they were seeing. Unprecedented. It's definitely the highest level they've seen in wastewater since February, possibly since, since further back than that, although it would take some extra analysis for them to be sure of that I've spoke with Dr. Christopher Longhurst who's, UC San Diego health, uh, chief in for information officer who basically said, you know, we have this major search coming and to buckle up and be ready for that. Also spoke with Rob Knight. Who's a gut bacteria and microbiome expert at U C S D. And one of the leaders of that wastewater surveillance effort, uh, P had some pretty stark language too. He said, you know, there's gonna be an unprecedented in cases, it's already in motion, but he felt that there was still an opportunity to keep, uh, what they're seeing in the wastewater and out of the hospitals, if we're able to respond quickly enough and, and, uh, strongly enough,
Speaker 1: (01:57)
Jonathan, can you remind us why the coronavirus can be detected in wastewater?
Speaker 2: (02:02)
Well, the short answer is it the virus infects your gut as well? You know, we usually talk about COVID 19 as being a respiratory disease and people having shortness of breath and severe pneumonia in certain cases, but it infects all different types of cells in your body, including the cells that line your intestine. So actually diarrhea is one of the symptoms that some people with COVID you have. Um, so in other words, if you're infected and you go to the restroom, you know, that virus that's in your gut is gonna be passing through, uh, your stool through your, your ex experiment as well. And so that's what researchers are detecting, uh, in this latest report.
Speaker 1: (02:38)
And where does UC San Diego, where do they collect these wastewater samples?
Speaker 2: (02:42)
So they get them from the point Loma waste water treatment plant. That's the facility in the county to process wastewater for about two thirds of San Diegos, essentially. That's what they've been getting their samples from and doing their analysis on since July of 2020.
Speaker 1: (02:57)
How did the research team detect Delta and Omicron variants in the viral load? I mean, doesn't that usually take longer take a week or so,
Speaker 2: (03:06)
Right. So usually you would need genetic sequencing to know what variant you're looking at. And that was one of the issues that U C S D was dealing with late Friday evening to, because they had seen just that overall levels of virus were, you know, shockingly high, but they didn't know if that had to do with Omicron, if it had to do with Delta, if it had to do with both, if there was something else going on there and they didn't wanna wait, you know, a week or two for the sequencing that to come through. So instead they relied on a different specific, the molecular tests that can distinguish one variant from another. So they've used this in the past to distinguish alpha from Delta and are now using it to separate Delta from OCN. So they were able to do some experiments, actually pretty early Saturday morning, you know, folks ran into the lab and were able to run some quick tests to see that it was both the Delta variant, which has been circulating for a while and the relatively new OCN variant. So, uh, Dr. Robert Knight actually was talking about this a sort of a two pronged pandemic at this point where you get these two variants that are spreading pretty quickly in our community.
Speaker 1: (04:14)
What's the length of time between detecting virus and wastewater, and perhaps seeing a wave of people actually getting sick.
Speaker 2: (04:22)
The folks I spoke with at U C S D said, it's typically about a week or two, uh, it can be up to three weeks in advance where you can see that much of a lag between a wastewater peak and virus and actual infections coming through. So that would roughly mean that sometimes I'm around early January, the start of the new year, you know, we would expect to see cases go up in a pretty, pretty significant way.
Speaker 1: (04:48)
What are the researchers at U C S D advising San Diegos to do about this?
Speaker 2: (04:53)
You know, they're saying if you're not vaccinated that you absolutely need to be, and we have about 400,000 folks in San Diego who are eligible for a vaccine, but have yet to get one, they're saying that if you are vaccinated, but haven't gotten a booster that you need that too, based on the data that's coming out on Omicron and on the power of boosters and giving you a higher level of protection against that variant. So there probably are many other folks who could get a booster at this point. You Haven on that. Uh, and then one of the other things you're saying is that regardless of who you are, uh, think carefully during the holidays about going to big indoor gatherings, where people are unmasked, and then, you know, Chris Longhurst at U C S D uh, added additional note, which was really to test test tests. So if you are feeling any kind of symptom, if you're planning on traveling, if you're planning on going to gatherings, if you think that testing might be a good idea, uh, then go ahead and do that because that's gonna allow us to get a better handle on what's going on in the weeks ahead.
Speaker 1: (05:56)
I've been speaking with San Diego union Tribune, biotech reporter, Jonathan Rosen, Jonathan. Thanks.
Speaker 2: (06:01)
An "unprecedented" spike in COVID-19 viral load in wastewater collected from San Diego County's primary wastewater treatment facility has been noted by UC San Diego School of Medicine researchers.
The amount of COVID-19 virus detected in wastewater has predicted the region's COVID-19 caseload up to three weeks ahead of clinical diagnostic reports, the researchers said Saturday. Since people with COVID-19 shed the virus in their stool even before they experience symptoms, wastewater screening acts as an early warning system.
"The wastewater screening results reported on Friday are unlike any the team has seen before," said Jackie Carr of UC San Diego Health.
Both delta and omicron variants of the virus were detected in the wastewater.
"This confirms prior county reports that omicron is already here and circulating in our community," said Dr. Wilma Wooten, San Diego County's public health officer.
"This is the steepest curve in viral load we've seen since we began screening wastewater in the summer of 2020, and it's continuing to get worse faster than ever before," said Rob Knight, professor and wastewater screening leader at UC San Diego School of Medicine.
Researchers and public health officials said they hoped the warning would encourage the local community to step up efforts to help mitigate the expected surge. In addition to wearing face masks in indoor public spaces, as recently mandated by California, they urged people to get their vaccines or boosters if they haven't already done so.
They also recommended downloading the CA Notify exposure notification system to smartphones, limiting time spent indoors or unmasked with others, and taking steps to improve indoor ventilation and air filtration.
"In addition, every person in San Diego County needs to have a low threshold for testing right now," said Christopher Longhurst, chief medical officer and chief digital officer at UC San Diego Health. "Don't wait. If you feel the slightest symptoms, if you think you might have had contact with someone with COVID-19, if you've gathered in crowds without masks, if you're planning a get together — test, test, test."
COVID-19 PCR tests are available at UC San Diego Health, various San Diego County sites, other health providers and community pharmacies. At-home rapid antigen tests are available from retail pharmacies and online vendors. Anyone who tests positive for COVID-19 should consult their health care provider.
San Diego County has only one primary wastewater treatment facility, in the Point Loma neighborhood. All excrement flushed away by nearly two-thirds of the county's residents, including those on the UC San Diego campus, ends up there.
UCSD researchers pick up wastewater samples that had been collected and stored for them by lab technicians at the treatment plant. They bring the samples to a lab at the La Jolla campus to test them for the COVID-19 virus, along with wastewater samples collected from more than 350 campus buildings. All positive samples are sequenced to track viral variants.
The team can detect even a single infected, asymptomatic person living or working in a large building of more than 500 people on the UCSD campus. They have found that notifying the occupants of each building with positive wastewater increases COVID-19 testing rates by as much as 13-fold. The approach has enabled early detection of 85 percent of COVID-19 cases on UCSD's campus, officials said.
And this information is important to people like Dr. Jess Mandel, chief of pulmonary and critical care medicine at UC San Diego Health. He said this data confirms what they’ve been expecting.
"We’re really preparing ourselves for the next wave of COVID infections that we’ve been expecting for some time," he said. "And with the emergence of the omicron variant, in where the timetable I think has shifted up but this is a very infectious variant and we expect to see a spike very soon."
This forecasted surge couldn’t be hitting at a worse time, Mandel said.
"I think the troubling thing for us is that this occurs on a backdrop of the hospital being extremely busy with non-COVID patients as well," he said. "And so you know the system is already being strained a little bit by everything else that’s going on and now we’ll probably have a big upsurge in COVID on top of it."
Hospitals are already seeing a steady rise in cases but most of the serious infections continue to be among the unvaccinated, Mandel said.
Despite local hospitals having plenty of personal protective equipment and other supplies on hand, Mandel and other doctors are worried about omicron being a game-changer.
"Really what we’re most concerned about is having enough people," he said. "Really the human resources because this variant is so infectious we expect that doctors, nurses and other folks will get infected along with others in the community and that really impacts our readiness and our ability to field the team."
So they are urging their staff to be extra vigilant
"We’re all in this together. That's what gotten us through and that’s what carries the day," Madel said. "But really, again, asking all of our folks to be incredibly careful, to, you know, mask like lives depend on it because they really do."