Background and aims Bronchiolitis is the most common lower respiratory infection in infants and a leading cause of hospitalizations in this age group. To describe the rhythm and seasonality of the yearly epidemics of bronchiolitis in hospitalised children.
Methods Epidemiological analysis of patients who were admitted to our hospital with bronchiolitis, over an 4-year period, from 2008 to 2012. The epidemic onset and conclusion was established according to the first and last cases per months, respectively.
Results Data was collected from 389 patients, mean age: 59 days (5–739), 59% male. The mean length of stay was 5,9 days (2–71). There was no risk factor in 87% (10% premature and 1,5% heart disease). The clinical score at hospitalisation was mild (4%), moderate (43%) and severe (2,8%). The RSV was positive 67%. Epidemics begin in October (50%) and November (25%); the highest peak was observed in January, February and December and its conclusion varies between March and July. There were no cases in August and September.
Conclusion Bronchiolitis epidemics onset is in October and November and conclusion varies along time years in hospitalised infants. The most incidence months are January and February with no cases in August and September. It not seems that a late season is followed by an early season in a 2-year pattern as is described but they alternate between greater numbers of patients with other patients less.