Role of cytomegalovirus infection in the incidence of viral acute respiratory infections in children attending day-care centers.

In a prospective study carried out in Lyon, France, the association between the excretion of cytomegalovirus (CMV) and the increasing frequency and severity of viral respiratory infections in children attending day-care centers was evaluated. Urine samples were collected in November 1992 (S1) and 4 months later in February 1993 (S4). A total of 246 children aged 6-12 months attending 29 day-care centers from 1 November to 28 February were screened for the excretion of CMV in urine. The diagnosis of viral acute respiratory infection was performed in the case of outbreaks only. Forty-eight (19.5%) children were both S1 and S4 positive for CMV, 30 (12.4%) became CMV positive (S1-/S4+), 4 (1.6%) became negative (S1+/S4-) and 164 (66.7%) remained negative. The percentage of children becoming CMV positive was significantly (P<0.001) higher in day-care centers where more than 40 children were enrolled. Nine outbreaks due to respiratory syncytial virus, rhinovirus and enterovirus were recorded in 8 of 29 (27.6%) day-care centers. Viral acute respiratory infections were significantly (P<0.05) more frequently recorded in day-care centers in which CMV and respiratory viruses cocirculated and were significantly (P<0.001) more frequently reported in CMV-infected children. These findings suggest that viral acute respiratory infections are significantly more likely to occur in CMV-infected children.

Daycare attendance and risk of first infectious disease.

The health hazards of daycare attendance for the development of upper and lower respiratory tract infections have been well documented; however the importance and the mechanism of this association have not been well defined. In order to ascertain the risk associated with the beginning of daycare (DC) attendance we conducted a survey on 1263 children aged from 3 months to 3 years; the analysis focused on the risk of developing an initial episode of common cold with fever, a first otitis and a first wheezy bronchitis (WB) within the 2 month period following admission to DC. For each 2 month period, the risk of a first infectious event was much higher in children who had just begun attending DC than in children who remained at home; the risk ratio varied from 1.7 to 2.4 for common cold, from 1.5 to 1.9 for otitis and from 1.8 to 3.2 for WB. Because age at onset of the first infectious event may be related to a higher risk of repeated events we consider that admission to DC under 12 months of age should be questioned.