[Prevalence of H1N1 A influenza virus infection among hospitalized patients with bronchiolitis twelve months old and younger].

Background: Many pathogens have been reported to ause bronchiolitis during the winter season including he respiratory syncytial virus (RSV), influenza, oetapneumovirus, etc. The last H1N1 A influenza pandemic ccurred during the respiratory syncytial virus (RSV) eason. The role of the pandemic influenza strain as a ause of bronchiolitis was not documented.

Objective: Assessment of the prevalence of co-infections of RSV and H1N1 influenza virus among children aged 12 months and younger, hospitalized with bronchiolitis.

Methods: A retrospective study design was used. Clinical data on 93 infants, 12 months old and younger, hospitalized for bronchiolitis, were retrospectively collected, including test results for RSV and H1N1 A influenza infection.

Results: Sixty-six out of the 90 (73.3 %) patients tested were positive for RSV; 2 out of the 81 patients tested (2.5%) were positive for H1N1 influenza. No patient was positive for both.

Conclusions: The results of the present study clearly show that in infants younger than one year of age, who suffer from upper and lower respiratory tract infection (bronchiolitis), the main pathogen is RSV (also appeared in the middle of he H1N1 A influenza pandemic last winter). We conclude that the H1N1 A influenza infection is uncommon in infants hospitalized with bronchiolitis during the winter season.