China discontinued its zero-COVID policy this winter, causing a rapid rise in infections. By testing wastewater on inbound flights from China, RIVM can detect any new variants of the virus that have not yet been identified in the Netherlands and elsewhere in the world.  Passengers and crew members infected with SARS-CoV-2 can excrete the virus, causing it to enter the wastewater from toilets on the aircraft. 

Coronavirus particles detected, but no new variants

Since 10 January 2023, a negative COVID-19 test result has been mandatory for passengers travelling from China. Even before this measure took effect, several samples of wastewater had been taken on inbound flights from China, and samples were also taken afterwards. Coronavirus particles were found in all samples. However, the first samples contained significantly higher levels of virus particles than samples taken after 10 January. The variants found in the samples were known variants, not new ones. The fact that coronavirus particles were also found in the later samples could be because the people on board the aircraft may also include transfer passengers who are not subject to mandatory testing. 

Sewage surveillance at Schiphol airport continues 

RIVM will continue testing samples from the sewage treatment plant at Schiphol in the upcoming weeks and months. Wastewater from inbound aircraft arriving at Schiphol and sewage from the airport itself ends up in this facility. RIVM has been testing these samples since February 2020. Samples from Schiphol are currently tested 4 times a week. No new variants have been found in sewage at Schiphol this year either, only variants that are already known.