Testing sewage for Covid could detect outbreaks early, scientists say

Sandra Laville
·3 min read
<span>Photograph: urbanbuzz/Alamy Stock Photo</span>
Photograph: urbanbuzz/Alamy Stock Photo

Scientists conducting tests for coronavirus in sewage to spot early warnings of where outbreaks are occurring say the approach is working and has helped reveal areas with high infection rates.

The programme has been piloted in the south-west of England since June. The sewage sampling data showed a spike in coronavirus content even though a relatively low number of people in the area had taken tests.

According to the government, the information was passed on to NHS test and trace and the local council, who were able to alert local health professionals to the increased risk and warn people in the area of the increase in cases.

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The programme has proved that fragments of genetic material from the virus can be detected in wastewater, the government added. Ministers said the information could provide local authorities with information to take early action to slow the spread of the virus.

Testing has been rolled out across more than 90 wastewater treatment sites in the UK, covering approximately 22% of the population in England, with plans to expand in the future, said the Department for Environment, Food and Rural Affairs.

Sampling is now being carried out at 44 sites in England, 24 in Wales and 28 in Scotland.

The environment secretary, George Eustice, said: “This is a significant step forward in giving us a clearer idea of infection rates both nationally and locally, particularly in areas where there may be large numbers of people who aren’t showing any symptoms and therefore aren’t seeking tests.

“NHS test andtrace is able to use the science to ensure local health leads are alerted and can take action.”

The government denied that the presence of the virus in untreated wastewater was a risk to humans, citing a study by Bangor University study that found the risk of transmission via faeces to be very low.

The World Health Organization view is that the likelihood of coronavirus being transmitted via sewerage systems is extremely low or negligible. There have been no reports of faecal−oral transmission of Covid-19 to date, according to the WHO.

However, a recent paper by scientists at the University of Stirling warned that the potential spread of the virus via sewage “must not be neglected” in the battle to protect human health.

News of the sewage testing method comes at a time of growing concern over the scale of the release of untreated sewage by water companies into rivers and seas.

Data obtained by the Guardian revealed in 2019 water companies discharged untreated sewage into rivers 204,134 times covering a period of 1.5m hours.

Hugo Tagholm, of Surfers Against Sewage, who are campaigning to stop the release of untreated sewage via storm overflows into rivers and seas, said testing for Covid-19 at sewage works was further evidence that water companies should take urgent action to prevent the huge number of sewage spills into our rivers and ocean that they preside over every year.

“Whilst transmission of the virus via sewage has not yet been clearly demonstrated, nor has it been ruled out,” he said. “This also shows why real-time information about sewage spills at popular recreational beaches and rivers is so important to safeguard public health.”