Detection of the novel variant of influenza virus A/H1N1v in bronchoalveolar lavage of adult hospitalized patients during the 2009/2010 winter season.

AIM

The aim of this study was to report most recent data regarding the occurrence of influenza A virus H1N1v in the lower respiratory tract from a cohort of hospitalized adult patients during the winter season 2009/2010 and investigated the main clinical features and outcomes.

METHODS

A total of 130 consecutive BAL specimens (collected from October 2009-March 2010) of 101 patients were retrospectively analyzed for influenza A virus H1N1v positivity using a commercial kit.

RESULTS

Overall, 19/130 (14.6%) BAL specimens from 17/101 (16.8%) patients were positive for the novel influenza A H1N1v virus. H1N1v resulted significantly more prevalent in immunocompetent subjects. As regards clinical features, H1N1v resulted more prevalent in respiratory insufficiency or acute respiratory illness. Thirteen patients died during the analytic period; three of them (23.1%) resulted positive to H1N1v but no direct association has been made.

CONCLUSION

Our cohort study of influenza A H1N1v detection in BAL from hospitalized adult patients confirms the overall moderate clinical impact of this virus, as reported in most reports worldwide. It remains to be evaluated the role of reassortment with influenza virus strains circulating in the winter season 2010/2011 and its potential pathogenicity.