Risk Factors for Virus-induced Acute Respiratory Tract Infections in Children Younger Than 3 Years and Recurrent Wheezing at 36 Months Follow-Up After Discharge

Background: We sought to know more about how 14 common respiratory viruses manifest clinically, and to identify risk factors for specific virusinduced acute respiratory tract infections (ARTIs) in children younger than 3 years old and for wheezing at 36-month follow-up. Methods: We retrospectively studied the clinical records for 273 full-term children (median age, 2.9 months; range, 0.26-39; boys, 61.2%) hospitalized for ARTIs, whose nasopharyngeal specimen tested positive for a respiratory virus and 101 children with no history of respiratory diseases (median age, 8 months; range, 0.5-36.5; boys, 58.4%). At 12, 24 and 36 months after children's discharge, all parents were interviewed by telephone with a structured questionnaire on wheezing episodes. Results: The most frequently detected viruses were respiratory syncytial virus in bronchiolitis, human rhinovirus in pneumonia and human bocavirus in wheezing. Multivariate analysis identified, as risk factors for virusinduced ARTIs, the presence of siblings [odds ratio (OR): 3.0 (95% confidence interval [CI]: 1.8-5.2)], smoking cohabitants (OR: 2.3 (95% CI: 2-4.2)] and breastfeeding lasting less than 3 months [OR: 0.5 (95% CI: 0.3-0.9)]. The major risk factor for respiratory syncytial virus-induced ARTIs was exposure to tobacco smoke [OR: 1.8 (95% CI: 1.1-3.2)]. Risk factors for human rhinovirus-induced ARTIs were attending day-care [OR: 5.0 (95% CI: 2.3-10.6)] and high eosinophil blood counts [OR: 2.6 (95% CI: 1.2-5.7)]. The leading risk factor for recurrent wheezing was exposure to tobacco smoke [OR: 2.5 (95% CI: 1.1-15.6)]. Conclusions: Each respiratory virus leads to a specific clinical manifestation. Avoiding exposing children to tobacco smoke might restrict viral spread from sick parents and siblings to younger children, prevent severe respiratory diseases, and possibly limit sequelae.