[Infectious risk in day-nursery children].

High proximity in daycare centers is a well established risk factor for upper respiratory tract infections as well as Haemophilus influenza meningitis. Many studies have also reported the development of gastroenteritis as well as hepatitis A outbreaks in daycare centers; however, because of lack of controls, these studies do not provide enough information about the excess of risk attributable to daycare attendance. Main risk factors such as age, or seasons, are still very important in daycare centers and studies have also shown that a protection occurs rapidly after the beginning of attendance, may be in relation to the stimulation of the non-specific immunity. All these results do not provide enough data to implement a rational intervention project. More studies have to be carried out to assess the long term consequences (at school age for instance) of these infections. In order to make a rational decision regarding daycare attendance, it is important to have a global assessment of all the effects related to attendance (which are numerous and sometimes opposite); studies focusing on a single aspect of daycare attendance, or on its short term effect, may result in partial and misleading conclusions.