The corona thermometer was introduced in September, as a successor to the risk levels. The thermometer has four positions: low, elevated, high and very high. On October 11, six weeks ago, the alert level went up for the first time, from low to high. This happened because the number of infections rose quickly and because vulnerable groups were at extra risk. Two weeks ago, RIVM kept the thermometer at ‘raised’ due to the emergence of a new subvariant of the virus.