Wastewater monitoring being used to track India variant, says Hancock

Wastewater monitoring is being used to identify cases of the India variant and track its spread, the health secretary, Matt Hancock, has said.

Although coronavirus predominantly infects cells lining the respiratory tract, it is also shed in the faeces of some infected individuals. By collecting sewage samples from wastewater treatment plants, scientists can use PCR (Polymerase chain reaction) machines to detect and quantify the amount of RNA from Sars-CoV-2 in different areas – including new variants, such as the B.1.617.2 variant first detected in India, which is now spreading across the UK.

The wastewater scheme was piloted last summer, and has since been expanded to include hundreds of sites across England, Wales, Scotland and Northern Ireland.

Speaking during the Queen’s speech debate earlier on Wednesday, Hancock told MPs that testing and vaccinations were being surged in six areas because wastewater analysis had identified places where the India variant was being transmitted.

He said: “Mobility data shows how often people travel from one area to another, and we look at this in deciding where the virus is likely to spread. And we analyse now wastewater, in 70% of the country, and we can spot the virus, and the variants in the water, to identify communities where there is spread.”

Although wastewater monitoring is not accurate enough to tell us how many individuals are infected with Covid in any given area at any given time, it can be used to understand where specific variants are circulating, and to provide an early warning of escalating cases in specific geographical areas.

This can be followed up with additional community testing and messaging, or the sewage equivalent of surge testing – where manhole covers are lifted up and samples taken from sewers in specific areas to try to narrow down the source of the outbreak.

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