The UK government has said analysing sewage to help identify coronavirus cases in areas where there has been limited testing for the virus can act as a valuable early warning signal of rising infections.
More than 90 wastewater sites are currently being tested across England, Scotland and Wales to detect the disease in the effluent from toilets.
Around 70% of Wales’s population is being tested currently using analysis of wastewater and 22% of the population in England, said the government, though these numbers are set to rise.
Data retrieved is sent to the NHS test and Trace system and also other regional bodies, which use them in deciding how to respond to outbreaks.
The advantage of testing wastewater is that it can pick asymptomatic carriers of the virus, which helps to fill in a gap in the UK testing system as most people who get tested have symptoms.
“We aren’t really testing for asymptomatic people,” Professor Davey Jones who is running the programme in Wales and the North-West of England told Sky News.
Schoolchildren who might have the virus, in particular, can be missed through the current testing regime.
Advocates believe the testing of wastewater can spot where spikes in infections are developing and globally will enable outbreaks to be caught early in places where there is not the infrastructure in place for mass testing.
“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,” Environment Secretary George Eustice said.
Countries such as the Netherlands already test widely using wastewater and plans are in hand to expand the UK scheme further, said Eustice.
Coronavirus traces in wastewater are not believed to be infectious.