Since March 2020, RIVM has been working with the water boards in the Netherlands to monitor sewage for traces of the coronavirus SARS-CoV-2. The measurements are an important supplement to other COVID-19 studies. For that reason, it has been decided to extend the research and expand its scope. Today, the Ministry of Health, Welfare and Sport (VWS), the water boards and RIVM concluded agreements on these efforts that cover the next five years.
At this time, samples of untreated sewage from all of the over 300 sewage treatment plants in the Netherlands are taken twice a week and sent to RIVM for analysis, with the aim of closely monitoring the spread of the virus. Sampling frequency will increase this year. The logistics to facilitate daily sampling at all locations are currently being arranged. This is expected to be possible by the end of this year.
It will eventually be possible to link a signal value or early warning indicator to the measurements. If virus levels in sewage provide a different indicator than COVID-19 test results in the test lanes, then the Municipal Public Health Services (GGDs) will receive an early warning, so further investigation can take place to determine what is going on and whether additional actions are necessary and possible. As Minister Hugo de Jonge (VWS) said today during a working visit to a sewage treatment plant in Leiden, “The measurements are an important extra check on top of standard testing. This enables us to keep a close eye on the virus and all its variants, even if it seems to be spreading less rapidly for a time. Via sewage research, the virus can be detected even before people develop symptoms.”
Coronavirus monitoring in sewage research also makes it possible to identify different variants of the SARS-CoV-2 virus. All samples are stored. If a new strain of the coronavirus emerges, then it will be possible to check if it is already present in the Netherlands once the genetic code has been analysed.
Indicator of public health
RIVM, the Ministry of Health, Welfare and Sport and the water boards are also exploring options for expanding the scope of sewage research in the future. Sewage surveillance already monitors for the presence of pathogens, such as antimicrobial-resistant bacteria. Sewage research could also be expanded to other areas, such as measuring medication and drug residues, microplastics and pesticides. Through these efforts, sewage could serve as an indicator of public health.