DETROIT – Researchers are still seeking ways to screen for coronavirus (COVID-19).
The testing of wastewater for evidence of COVID-19 is showing promise. A new paper suggests it could provide a very early warning of an impending outbreak.
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The main way epidemiologists have followed the growth of the pandemic is through testing individuals. Those results will be delayed from the date the person actually first becomes infected. Wastewater testing will detect a problem much sooner.
If you are infected with the coronavirus, there’s a good chance it will show up in your poop. Early on in the outbreak, it was found that the SARS-CoV-2 virus is shed from the intestinal tract. Many infected people develop intestinal complaints.
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Researchers at both Michigan State University and the University of Michigan have already started looking at how wastewater testing could be used to detect COVID-19 outbreaks on their campuses.
The idea of screening wastewater for evidence of viral outbreaks isn’t new. It’s proved useful before in identifying polio resurgences before they grew out of control.
Yale University researchers have found wastewater can effectively be used to give an early warning of an increase in COVID-19. They evacuated samples of wastewater sludge for the presence of SARS-CoV-2 genetic material and compared the amount found in the waste to community data on infection rates.
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The research found viral RNA counts in sewage increased two days before an increase in positive specimens collected from people, but more importantly a full six to eight days before those results became available due to delays in nasal swab processing. It also preceded an increase in hospital admissions by one to four days.
By monitoring the amount of SARS-CoV-2 genetic material in sewage it is possible to get warning of an increase in infection about a week earlier. Even before individual tests return positive because of potential processing delays.
This only gives an indication of changes in the amount of coronavirus that is present in the entire group of people whose sewage is being collected. It doesn’t give any individual information.