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This study was designed to collect data on the prevalence of respiratory syncytial virus (RSV) infection in Italy in infants hospitalized for lower respiratory tract infections, and to evaluate which of the recognized risk factors might be associated with disease severity. Thirty-two centers throughout Italy participated in the study. Over a 6-month period (November 1,1999 to April 30, 2000), we evaluated all children < 2 years of age hospitalized for lower respiratory tract infections. All subjects were tested for RSV within 24 hr of hospitalization by using an immuno-enzymatic diagnostic test (Abbott Testpack, RSV). Logistic regression was used to identify the factors that might be associated with more severe disease or could increase the likelihood of RSV positivity in hospitalized infants. Out of a total of 1,232 children enrolled, 40.6% were found to be RSV-positive (RSV+). The peak of the RSV epidemic occurred in February, while the lowest prevalence of RSV positivity was seen in November (P < 0.05). A high proportion of study subjects had low birth weight and low gestational age. The clinical diagnosis at hospitalization was bronchiolitis in 66.7%, pneumonia in 15.3%, and wheezy bronchitis in 18.1%. In the bronchiolitis group, a higher prevalence of RSV+ was found in patients with gestational age or= 36 weeks (P < 0.04). No differences were found in the proportion of RSV+ patients in the three gestational age subgroups with pneumonia and wheezy bronchitis (P > 0.05, each comparison). Independent of the clinical diagnosis at admission, RSV infection was associated with more severe respiratory impairment. Environmental smoke exposure was higher in subjects with bronchiolitis than in those with wheezy bronchitis (P < 0.04), and RSV+ was positively related with the birth order (P < 0.05). The presence of older siblings and birth order plays an important role in RSV infection. The collected data show that, in Italy, RSV is an important cause of lower respiratory tract infection in infants. Gestational age, birth order, birth weight, and exposure to tobacco smoke affected the prevalence and severity of RSV-related lower respiratory tract disease.

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We evaluated bronchoalveolar lavage fluid (BAL) for cellular constituents, concentration of total protein (TP), albumin (AL), fibronectin (FN), and hyaluronic acid (HA) in 16 children aged 2-32 months without pulmonary inflammatory or parenchymal disease to establish reference values. We compared our data to those reported in older children and in normal adult volunteers. BAL results were obtained simultaneously from the right middle lobe and the lingula. Results indicated that children younger than 3 years of age had a higher number of cells/mL than older children and adults (59.9 x 10(4) vs. 17.6 x 10(4) and 12 x 10(4)). Differential cell count revealed that the percentages of alveolar macrophages (AM), lymphocytes (LYM), and eosinophils (EOS) were similar to those obtained in older children and in adults, whereas the percentage of neutrophils (NEU) was higher in younger children (NEU 5.5 vs 1.6 and 1.2%, respectively) than in older children and adults. The latter difference was even greater in infants under 12 months of age (NEU 7.6%). The concentrations of TP, AL, FN, and HA in children's BAL samples were compared to values reported for adults. There were no differences between infants and children 13-32 months of age or normal adults. BAL fluid obtained simultaneously from the middle lobe and lingula were not significantly different. In conclusion, this is the first report on BAL values (cellular and noncellular constituents) in children younger than 3 years. The results may be used as reference values for further studies in children with parenchymal lung disease in this age group.

Variability in severity among different respiratory syncytial virus (RSV) seasons may influence hospital admission rates for RSV-induced lower respiratory tract infection (LRTI) in young children. The aim of the present study was to identify through logistic regression analysis, risk factors associated with higher likelihood to acquire RSV-induced LRTI, in children with symptoms severe enough to lead to hospital admission. Over four consecutive RSV seasons (2000)(2001)(2002)(2003)(2004), records from children <4 years of age admitted for RSV-induced LRTI ("cases") were compared with those from children with LRTI not due to RSV and not requiring hospitalization ("controls"). 145 "case-patients" and 295 "control-patients" were evaluated. Independent from the severity of the four epidemic seasons, seven predictors for hospitalization for RSV infection were found in the bivariate analysis: number of children in the family, chronological age at the onset of RSV season, birth weight and gestational age, birth order, daycare attendance, previous RSV infections. In the logistic regression analysis, only three predictors were detected: chronological age at the beginning of RSV season [aOR=8.46; 95% CI:3.09-23.18]; birth weight category [aOR=7.70; 95% CI:1.29-45.91]; birth order (aOR=1.92; 95% CI:1.21-3.06). Conclusions: Independent from the RSV seasonality, specific host/environmental factors can be used to identify children at greatest risk for hospitalization for RSV infection.