As colleges across the U.S. scramble to ensure the safety of their students amid the COVID-19 pandemic, the University of Arizona revealed this week that an unusual test may have allowed it to stop an outbreak before it began. The special specimen? Sewage.
Wastewater, for those unfamiliar with the term, is water that has been contaminated through human use, leaving behind things like food, oil, chemicals and human waste. Wastewater base epidemiology, as the technique of studying it is called, is a fairly new concept, which has been used to explore things like human exposure to toxins or to help locate cases of polio.
Now, thanks to a sophisticated RNA testing process, multiple colleges have begun quietly performing wastewater analysis in hopes of circumventing smaller COVID-19 outbreaks before they happen.
The University of Arizona, one of the first to discuss its analysis publicly this week, has been doing routine wastewater testing since March, analyzing the sewage of 20 different buildings, including multiple dorms. This week, after the wastewater from one dorm showed copies of SARS-CoV-2 (the scientific name of the virus that causes COVID-19), administrators tested all 311 individuals who lived there and discovered two asymptomatic cases.
Related: Is coronavirus sewage testing the key to slowing COVID-19?
In a press conference Friday afternoon, Ian Pepper, an environmental microbiologist and director of the university’s Water and Energy Sustainable Technology Center, told reporters it’s a perfect example of what the test can do — predict an outbreak before it occurs. “It’s a leading indicator,” Pepper says of the wastewater. “The virus shed by individuals happens seven days prior to visible symptoms, and so you have seven precious days in which you can undergo intervention, and it’s particularly useful for detecting the onset of a pandemic.”
Aaron Best, chair of the biology department at Hope College in Holland, Mich., has been carrying out the same tests on his campus. He says the process is complicated, requiring his team to monitor multiple sewers, pull and pump samples every 20 minutes using a device called an autosampler, and then produce a composite to be tested.
But this testing mechanism doesn’t just tell him if someone is positive, but how many people are positive. “So instead of just getting a yes-no answer, you get a ... how many copies of the virus did I detect in this sample?” Best tells Yahoo Life. Like Pepper, he notes that one of the advantages is that the shedding often occurs before symptoms have emerged, meaning there is still time before an outbreak begins.
“It’s possible that the signal that you see in the wastewater is actually a leading indicator of when you would actually see cases come up in a clinical setting ... and it might even tell you about things when they never would have known,” says Best. “So the idea is that there is possibly this lead time — could be anywhere from four days to 10 days ... so you could say, ‘I’m going to have an outbreak going on in 10 days from now where I’m seeing it. What can I do now to mitigate that?’”
Best is quick to note that the test isn’t some miracle fix that could replace other testing protocols. “I wouldn’t consider it to be a panacea,” he says. “I think this has to be part of a comprehensive testing strategy that would include ... asymptomatic testing, some kind of surveillance level, wastewater testing, symptomatic testing and of course then the correct follow-up procedures such as contact tracing. It’s kind of pool testing of sorts — sort of the same concept. It’s just your starting sample isn’t saliva or a nasal swab, it’s sewage.”
Dr. Michael Mina, assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health, applauds the concept. “I think it’s very valuable — it’s a really creative and true public health approach to this virus,” says Mina. But although he commends the creativity, he’s not optimistic about widespread applicability. “We have seen ... cases increase [a few months ago] in Massachusetts, and we saw that from the wastewater data that we were getting. So I think that it’s a terrific approach. But I think people have to understand that it’s not the most scalable thing at the moment. You can do it at a university, but then there have to be a lot of resources to put in place for how to act on it.”
For the latest coronavirus news and updates, follow along at https://news.yahoo.com/coronavirus. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.
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