Swiss cut Covid-19 wastewater monitoring by half

Wastewater samples will continue to be taken and tested three times a week to determine the SARS-⁠CoV-⁠2 viral load at 50 plants, the Federal Office of Public Health (FOPH) says. © Keystone / Gaetan Bally

The number of waste treatment plants used to monitor the spread of Covid-19 in wastewater in Switzerland has been cut by half following a cost-benefit analysis. This comes after a decision by parliament to end free Covid tests in Switzerland from January 1, 2023.

Currently around 100 waste treatment plants belong to a wastewater monitoring network providing regular detailed assessments of Covid’s evolution nationwide. From January 1, 2023, the network will be reduced to 50 facilities, covering 44% of the population compared to 70% at present.

Wastewater samples will continue to be taken and tested three times a week to determine the SARS-⁠CoV-⁠2 viral load at the 50 plants, the Federal Office of Public Health (FOPH) said on Thursday, confirming an earlier storyExternal link by Heidi.news.

According to the news site, the reasons behind the cut are more financial than health-related.

“This 50% reduction comes after an assessment of the cost-benefit ratio of such monitoring by the FOPH,” Heidi.news wrote.

A FOPH spokesperson said the health office constantly monitors the cost-benefit ratio of infectious disease monitoring projects, adding that parliament is responsible for budgetary decisions.

The decision to reduce the network was taken to get an “optimal estimation of the epidemiological situation with the resources and waste treatment plants available”, the spokesperson added.

Wastewater sampling will continue to be carried out in every canton while allowing coverage of the largest proportion of the Swiss population as possible, the health office said. Cantons are free to expand the monitoring network if they bear the costs.

The progression of Covid in Switzerland will continue to be monitored using four indicators: wastewater monitoring, reporting of official test cases, the Sentinella reporting system [of 150-250 Swiss GPs], and the monitoring of viral variants via sequencing, the FOPH said.

The decision to cut the national wastewater monitoring network by half comes after parliament decided Covid tests will no longer be reimbursed by the federal authorities for people with symptoms from January 1, 2023. This was criticised by a top medical official as misguided, sending the “wrong signal” this winter.

A new wave of coronavirus infections and hospital admissions emerged in Switzerland in September; numbers have since stabilised at a high level. A total of 16,362 new Covid cases were reported on December 13 for the previous seven-day period, down 12% on the previous week. Health officials nonetheless say there are a high number of unreported new infections.