RIVM draws up the guidelines and protocols for testing for the coronavirus SARS-CoV-2 and for source and contact tracing, working in cooperation with doctors, microbiologists and GGD GHOR. The Municipal Public Health Services (GGDs), laboratories and hospitals carry out the tests. The quality of the tests being offered is very important in this context.

Some groups of people have a higher risk of severe illness resulting from the coronavirus SARS-CoV-2. They are particularly vulnerable. People who are at higher risk can take their own measures to protect themselves, without restricting contact with others more than necessary.  

Between the current round (19-23 January 2022) and the previous round (24-28 November 2021) of the survey-based study, the Omicron variant became dominant in the Netherlands. The previous survey round took place just before the lockdown was announced, while the current round was just before the lockdown ended. During the current survey round, many venues were still closed, including cafés, restaurants and cultural institutions.