Scientists are developing ways of using sewage to locate new infection hotspots and track a second wave of COVID-19.


An international group of waste water experts are researching new techniques that could identify the level of infection in a community without the need for testing individuals.

New standardised procedures could identify the virus in waste water and provide a picture of how coronavirus is spreading, the researchers said.

The group, who were brought together by the Water Research Foundation and include engineers from the University of Sheffield, are developing a range of best practices concerning the use of sewage.

These include collecting and storing waste water samples and using molecular genetics tools to identify levels of COVID-19 in sewage samples.

The scientists are also developing recommended approaches for using levels of coronavirus in waste water samples to inform trends and estimates of the spread of the virus in communities and developing strategies to communicate the implications of the results with the public.

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Professor Vanessa Speight, from the University of Sheffield’s Department of Civil and Structural Engineering, is researching techniques to reliably interpret the data collected from sewage samples.

Her results could help create a more accurate map of how the virus is spreading and show the emergence of a second wave of the pandemic.

She said: “There is great potential for waste water to provide valuable information about the occurrence of COVID-19 across communities.”

(Sewage samples could) track if the virus is more prevalent in some parts of the country than in others
Downing Street spokesman

On Monday, Prime Minister Boris Johnson said a new alert system to monitor the threat posed by coronavirus could eventually identify local flare-ups if COVID-19 is detected in the waste water from a local area.

The PM’s official spokesman said: “Some studies have been carried out overseas on this and I think it is something we are looking at as a possible way of seeing if you could track the rate of infections locally.”

The Downing Street spokesman said officials are investigating whether sewage samples would allow them to “track if the virus is more prevalent in some parts of the country than in others”.

A family in Bradford watch Britain's Prime Minister Boris Johnson give a televised message to the nation to announce a new alert system and a possible timeline for the gradual lifting of the lockdown on May 10, 2020 in Bradford, England. The UK is continuing with quarantine measures intended to curb the spread of Covid-19, but as the infection rate is falling government officials have been discussing the terms under which it would ease the lockdown. (Photo by George Wood/Getty Images)
A family in Bradford watch Britain's Prime Minister Boris Johnson give a televised message to the nation to announce a new alert system on Sunday © George Wood/Getty Images

Experts said some countries are testing waste water to see if there is an infection in the community.

And, while there is no evidence of the live virus being found in sewage or that the virus has been spread through sewerage systems, one study from the Netherlands found viral genetic material in waste water samples several weeks before the first case was detected.

A spokesman from the Department for Environment, Food and Rural Affairs (Defra) said: “We are actively engaging with the research community and Government scientific advisers to investigate whether monitoring waste water could be used as a way of tracking the prevalence of the virus.”


Last month, scientists from Newcastle University said they were collaborating with Spanish academics to monitor sewage in their local networks in both countries to estimate the prevalence of COVID-19 in north-east England and across Spain.

Reader Q&A: Why don’t viruses like the flu die off when no one is ill?

Asked by: Andrew Cirel, via email

Strictly speaking, viruses can’t ‘die off’ as they’re just inanimate strips of genetic material plus other molecules. But the reason that they keep coming back is because they’re always infecting someone somewhere; it’s just that at certain times of the year, they’re less able to infect enough people to trigger a full-blown epidemic.

Many viruses flare up during the winter because people spend more time indoors in poorly-ventilated spaces, breathing in virus-laden air and touching contaminated surfaces. The shorter days also lead to lower levels of vitamin D, and this weakens our disease-fighting immune system. Experiments also suggest that the flu virus in particular remains infectious for longer in low temperatures.

But even when conditions aren’t ideal, viruses will find enough people to infect to ensure their survival, until they can come roaring back in an epidemic.

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Alexander McNamaraOnline Editor, BBC Science Focus

Alexander is the former Online Editor at BBC Science Focus.