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With the end of other virus-tracking efforts, wastewater information is expected to become increasingly important in the coming months, scientists say.
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By Émilie Anthès
When the Covid-19 public fitness emergency expires in the United States on Thursday, the coronavirus will disappear. But many of the knowledge streams that have helped Americans monitor the virus will disappear.
The Centers for Disease Control and Prevention will avoid collecting network levels of Covid-19 and will no longer need secure data on hospital cases or laboratory testing data. have resorted to home verification, possibly it would be more eliminated from reality.
But experts who need to keep an eye out for the virus will have a valuable option: sewage.
People infected with the coronavirus are shedding the pathogen in their feces, whether they get a covid test or seek medical attention, allowing officials to track levels of the virus in communities over time and monitor the emergence of new variants.
This technique evolved during the pandemic. The National Wastewater Monitoring System, which the CDC established through the end of 2020, now includes information from more than 1,400 sampling sites in 50 states, 3 territories and 12 tribal communities, said Amy Kirthrough, program manager. Knowledge covers about 138 million people, or more than 40% of the U. S. population. “The U. S. government,” he said.
And as other monitoring efforts come to an end, some communities are rushing to install wastewater tracking systems for the first time, Dr. Anna Stuart said. Kirby. ” There is more and more interest in wastewater,” he said.
In the coming months, monitoring wastewater will become even more important, scientists say, and deserves to help the government spot some emerging outbreaks.
But many communities still lack wastewater monitoring, and more paints are needed for what began as an ad hoc emergency effort in a sustainable national system, Mavens said. And leaders will want to think about how they use knowledge as the pandemic continues to evolve.
“Wastewater wants to get better,” said David O’Connor, a virologist at the University of Wisconsin-Madison. “And we want to be a little wiser in interpreting what wastewater knowledge tells us. “
Over the past 3 years, tracking tewater has been proven time and time again. When testing was widely available, wastewater trends mirrored the official number of Covid-19 cases. When testing was scarce, spikes in viral levels in wastewater provided early warnings of increases to come, allowing officials to redeploy public health resources and hospitals to prepare for an influx of cases.
Wastewater sampling has helped scientists when new variants have reached specific communities and has helped doctors make more informed decisions about when to use certain treatments, which probably wouldn’t oppose all versions of the virus.
“For SARS-CoV-2, our wastewater tracking formula is now pretty robust,” said Marisa Eisenberg, an infectious disease epidemiologist at the University of Michigan. “We put it to the test. “
Houston, for example, now has an extensive wastewater tracking infrastructure, collecting samples weekly from the city’s 39 wastewater treatment plants, as well as from schools, shelters, nursing homes and prisons. The city has no plans to cut spending, said Loren Hopkins, environmental science lead for the Houston Health Department and a statistician at Rice University.
“We don’t know what covid will do,” he said. We will continue to monitor the wastewater to know how much virus there is. “
The C. D. C. will track deaths and hospitalizations, but they tend to be lagging indicators. Therefore, it is very likely that wastewater will remain a must-have early precaution formula for public servants and members of the public.
“This can help immunocompromised people, who may need to be very careful,” said Alexandria Boehm, an environmental engineer at Stanford University and principal investigator of WastewaterSCAN, a wastewater tracking initiative. A really crowded concert. “
As clinical trials wind, monitoring wastewater will also be a key strategy for being aware of new variants and assessing the risk they pose, the scientists said. For example, it would possibly justify building UPD surveillance.
However, knowledge will not be had everywhere. Since the existing wastewater tracking formula emerged randomly, with acceptance from the jurisdictions involved, the country’s politics are uneven. Wastewater sampling sites tend to be infrequent, or absent, in many rural spaces and parts of the South and West. .
And collecting wastewater information is just the first step. Understanding this could be more complicated, the scientists warned.
Among the demanding situations they cited: Now that many Americans have developed some immunity to the virus, spikes in wastewater may not necessarily lead to the same wave of hospitalizations that some services expect. And scientists don’t yet know if all variants will be similarly detectable. in wastewater.
In addition, simply detecting a new variant in wastewater does not necessarily portend a problem. For example, since 2021, Marc Johnson, a virologist at the University of Missouri, and his colleagues have discovered dozens of variants in wastewater samples in the United States.
Some of those variants are radically different from Omicron and, in theory, may pose a new public health risk. But so far, at least, those variants don’t appear to be spreading. Most likely, they come from individual patients who get rid of coronavirus infections for a long time. “Term,” Dr. Johnson said.
“Wastewater is smart because it can give you a complete view of what’s going on,” Dr. Johnson said. But there are times, he says, “when they can confuse you. “
And while a relief in tracking covid cases is likely inevitable, wastewater surveillance is more informative when combined with other public knowledge resources about fitness, the scientists said. “I like to think of it more as a complementary knowledge stream,” Dr. Eisenberg said. saying.
Wastewater tracking will continue to evolve, Dr. Kirby said. The CC is discussing with some states how to optimize their network of sampling sites, a procedure that may involve adding new sites and cutting them into spaces where sampling sites provide necessarily redundant data. .
“We expect some relief in the number of sites in some of those states,” Dr. Kirby said. “But we’ll work with them to be strategic about it, so we don’t lose information. “
Officials are also exploring other possibilities. As part of CDC’s Genomic Surveillance of Travelers program, for example, Ginkgo Bioworks, a Boston-based biotechnology company, has recently obtained wastewater samples from aircraft landing at the foreign terminal at San Francisco International Airport.
“It’s important to set up those oblique mechanisms that can give you insight into what’s going on in the world, as another testing bureaucracy starts to fall down,” said Andrew Franklin, director of business progression at Concentric through Ginkgo, the company. Biosafety and Public Health Branch.
The US bailout has provided enough investment to track wastewater in each and every state and territory through 2025, Dr. Kirby said.
But keeping track of wastewater will require continued longer-term funding, as well as continued buy-in from local authorities, some of whom would possibly lose interest as the emergency phase of the pandemic comes to an end. “dropouts based on fatigue,” said Guy Palmer, an infectious disease pathologist at Washington State University and chairman of the Wastewater Monitoring Committee of the National Academies of Sciences, Engineering and Medicine.
Proponents of wastewater tracking hope to demonstrate its continued usefulness, whether for Covid-19 and other diseases. Some jurisdictions already use wastewater to track influenza and other pathogens, and CDC expects to implement expanded testing protocols through the end of the year. Kirthrough said.
“It’s a component of our long-term surveillance portfolio,” Dr. Kirby said. “I think we’re going to see how difficult it can be once we get out of that emergency reaction period. “
Emily Anthes is a reporter at The Times, where she focuses on science and fitness and covers topics such as the coronavirus pandemic, vaccines, viruses and covid in children.
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