Tracking COVID-19 through the sewers

A team of geneticists from New Zealand are sampling wastewater for information on the spread and containment of corona virus in their cities. The high proportion of asymptomatic carriers reported in Italy and South Korea have shown how difficult it is to know for sure if the virus has been eliminated, or if it is just hiding in plain sight. With a vaccine at least 18 months away, the world is leaning heavily on time-consuming testing regimes to track the spread of the virus. According to this team, however, a better solution might just be in our sewers.

If the toilet paper shortages have reinforced anything it’s that ‘everyone poops’, so why not use that to our advantage? SARS-CoV-2 is a hearty virus, surviving happily in wastewater for 2 to 4 days before dying off. This means that daily samples from wastewater treatment plants could provide updates on the presence of the virus in our communities. “The aim is to monitor the presence, and potentially the abundance, of the virus in our communities,” Professor Neil Gemmell has said of the research, “Depending on what we find we could then make some predictions about which communities would be able to come out of lockdown or go back into lockdown because Covid-19 was circulating.”

For now, the study is still in the pilot phase with Neil expecting that adjusting the sensitivity of the test, and ensuring overall reliability is expected to “take months, not days.” The process involves comparing the viral load in swabs and faecal samples of COVID-19 patients against the load in the untreated sewage. All things considered, the process doesn’t sound enticing, but Neil and his team are enthusiastic about the work and its potential for providing clarity in this murky situation. “It can add an extra element, perhaps helping to identify virus circulating in asymptomatic carriers,” Neil says, “Likely as cases get lower this is where virus may persist and we might determine that, ‘Nobody’s reported sick in this community but there’s still Covid circulating so we have to go in and have a look’.”

In this ever-evolving situation, information is our best weapon and testing is our holy grail. This trail through the sewer isn’t meant to eliminate the swab-tests that you might get from your doctor, but it could go a long way in supporting it. Once this is over, and it will be eventually, this could be the final test to show that corona virus is gone once and for all.

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