Japan eyes sewage monitoring pilot project to understand spread of COVID-19

The Yomiuri Shimbun

15:57 JST, June 3, 2022

The government will launch a major pilot project this summer to monitor the presence of the novel coronavirus in sewage, aiming to develop an early-warning system to detect the spread of the virus and implement effective pandemic measures.

Testing will be conducted at about 40 test sites at facilities nationwide, including wastewater treatment plants, schools and elderly care homes. As coronavirus can be detected in the feces of infected people, by checking virus levels in the sewage system, it is possible to determine the infection situation in a particular region or location.

Wastewater surveillance, which does not require testing people individually, can also be used to detect asymptomatic cases, making it possible to swiftly mitigate the spread of infections and the emergence of clusters.

However, such monitoring has yet to become fully established because the accuracy of results is dependent on various factors, including the volume of sewage and the sampling duration.

According to the Cabinet Secretariat, more applications than expected were received from entities that wished to participate. It plans to narrow down the candidates from the applications received so far.

In the pilot project, data will be collected at wastewater treatment plants to determine the number of infections per week and the infection trends in the respective areas. If the virus is detected in wastewater at facilities such as schools and care homes, follow-up PCR tests will be conducted to check the consistency of results from sewage surveillance.

Such methods have already been utilized to monitor COVID-19 cases in countries including the United States and the Netherlands.

In Japan, however, sewage surveillance is still in the testing phase, with projects being conducted by universities, local governments and companies. A research group comprising Tohoku University and other entities posts weekly estimates of infection cases in Sendai. The group tests sewage samples collected from a wastewater treatment plant in the city and uses a calculation method to predict the number of infection cases.

In the week ending May 29, 1,786 coronavirus cases were officially confirmed in Sendai. According to estimates released by the group, sewage surveillance indicated that there could have been as many as 2,172 cases in the city that week.