Frédérique Jacobs, a physician and spokesman for the crisis Centre, explained the decision of the national security Council by presenting a simulation carried out by the University of Antwerp and University of Hasselt. "You see that the red graph shows about the evolution of hospital admissions in a context of a bubble of 15 people who changed every week, as we knew it previously. The green curve gives a rough idea of the effect of the new bubble social in which we see only 5 people during the next four weeks. We see that the effect is quite important, " she stressed.