STOCKHOLM — A technology institute in Sweden has found large concentrations of the coronavirus in Stockholm’s sewage system, saying it “has doubled in the last weeks and is now back at the same levels as in May 2020.”

In a statement, the KTH Royal Institute of Technology said the increased number of cases of COVID-19 in recent weeks is reflected in the wastewater and thus not due to more people being tested.

“My interpretation is that this latest increase is definitely about an increased number of infected people in society,” said Cecilia Williams, a professor at the institute in Stockholm.

Sweden, which has opted for a much debated COVID-19 approach of keeping large parts of the society open, has reported 94,283 cases and 5,895 deaths.