Nationally, the vaccination rate is too low at 89 percent. The province of Utrecht does slightly better with an average of 90.8 percent, but is still below the standard. “It is certainly something we look at with concern,” says Putri Hintaran, infectious diseases doctor at the GGD region of Utrecht. “Without herd immunity, vulnerable people, for example with an immune disorder, are no longer protected. This can cause them to become (seriously) ill.”