Don’t expect Utah to monitor wastewater for monkeypox anytime soon.
“I think it will be quite a while before we know how reliable that information would be,” said Utah’s state epidemiologist, Dr. Leisha Nolen, even though the state is already regularly testing sewage samples for COVID-19 and may soon do the same for polio, after New York reported the nation’s first case in nearly a decade.
The reason? Well, it has to do with whether monkeypox can be counted to show up in what’s flushed down a toilet or washed down a drain. Nolen said it’s not yet known if the monkeypox virus is excreted in urine and feces, like COVID-19 and other diseases.
“As you can imagine, for wastewater surveillance to be useful for disease, that disease has to get into the wastewater. So, for SARS-CoV-2 (COVID-19), it was very good because we know people poo out the virus, right? That’s the blatant way to say it. And it gets into our sewage system,” she said.
If that’s not true for monkeypox, Nolen is concerned signs of at least some infections might never make it to the sewage system, although she said the virus, which results in a rash that turns into fluid-filled pustules, could still find its way into wastewater depending on where the pustules are located.
In places that have detected monkeypox through wastewater surveillance, Nolen said it’s unclear if that’s because those were cases with lesions in the groin area, so the virus was passed into the sewer system along with body waste. Cleansers may make it difficult for the virus to appear in wastewater from sinks or showers.
“This is really in the very beginning,” she said, adding, “if we detect it in wastewater, we can say, ‘OK, clearly somebody in the community has it.’ But if we don’t detect it in the wastewater, we have no idea what that means. Does it mean nobody has it? Or does it mean nobody has it right around where they stool and urinate?”
Monkeypox was discovered for the first time in wastewater in the United States in June, in San Francisco after researchers at the Sewer Coronavirus Alert Network, or SCAN, started tracking the virus in samples from communities in California, Idaho, Colorado and more than a dozen other states nationwide with plans to expand.
The network — led by scientists at Stanford University in California and Emory University in Georgia as well as Verily Life Sciences, a subsidiary of Google’s parent company — is considered a leader in wastewater monitoring, but some places are conducting their own surveillance, including Utah.
Nolen questioned whether testing wastewater for monkeypox is needed in Utah, at least in the parts of the state where it has already been identified. As of Aug. 25, the Utah Department of Health and Human Services reported there have been 92 cases of monkeypox in the state since May, compared to nearly 17,000 nationwide.
“Right now, we know that it’s in our community,” the epidemiologist said.
Nearly three-quarters of the cases identified are in Salt Lake County, with the rest in Davis, Summit, Tooele and Utah counties, as well as in areas served by the local health departments for Weber and Morgan counties, and for Daggett, Duchesne and Uintah counties.
In those places, “collecting that kind of data is not super useful. I guess in some other areas where they haven’t had cases detected, then wastewater could help us,” Nolen said, although public health officials are already reaching out to those viewed as most likely to contract monkeypox, men who have sex with men.
More than 3,000 Utahns have been vaccinated against monkeypox, according to the state. The shots are not available to the general public, but are being offered to individuals who’ve had intimate contact with someone who has monkeypox or men who have had multiple male sex partners in recent weeks, particularly in group settings.
Nolen said other Utahns should be on the lookout for any rashes that develop if they’ve been in close contact with people who could be infected with monkeypox, such as rubbing up against strangers in a crowd, although transmission requires significant skin-to-skin contact.
“It’s not people they’re shaking a hand with. It’s not a person they’re sitting next to and they accidentally bump arms,” she said. “For most Utahns, it’s not something that we need to have in mind at this point. I don’t want to promise it’s going to go there, but I think right now, it’s not something I want people to worry about.”
Jim Vanderslice, a University of Utah School of Medicine professor in the public health division of the Department of Family and Preventive Medicine, said when it comes to monitoring wastewater for diseases, monkeypox is lower on the list.
“It’s a matter of priorities. I think it could be interesting but I don’t see it as much of a priority,” Vanderslice said, describing the ongoing testing for COVID-19 as “important. I think polio would be useful. And again, it comes down to time and effort and money to do so.”
Vanderslice, who along with other academic experts helped the state start up wastewater monitoring for COVID-19 shortly after the start of the pandemic in March 2020, said the general aim of such surveillance is to identify whether something is present.
“It’s pretty sensitive to tell you no, and it’s pretty sensitive to tell you yes. So you can start getting a sense of, OK, is this in this population or not,” he said. “Once it’s in the population the relationship between what’s the concentration that you see in the wastewater and the burden in the community is a lot more difficult to establish.”
That’s because there’s a lot of variability in how much virus an individual sheds or for how long, Vanderslice said, as well as in other factors like sewage system conditions, that make it difficult to equate what’s found in the samples to a specific number of cases.
Trends, however, “tends to be something that’s a little bit easier to detect, because going up, going down, is easier to observe than an actual number,” he said, adding that with wastewater surveillance, “how good it works really depends on what you’re trying to use it for.”