title: Influenza A(H1N1)pdm09 and postpandemic influenza in Lithuania.
abstract: The objective of this study is to describe the clinical and epidemiological characteristics of patients hospitalized in Lithuania who are infected with influenza A(H1N1)pdm09 and to compare pandemic A(H1N1) pdm09 infection with postpandemic. In total, 146 subjects hospitalized with influenza A(H1N1) pdm09 were identified from 2009-2011. There were 53 during the initial pandemic wave in the summer of 2009, 69 during the peak pandemic period, and 24 during the "postpandemic" period that we included in this study. There were 22 subjects who died after laboratory confirmation of influenza A(H1N1)pdm09. No deaths were documented during the first wave. Subjects presenting during the peak of pandemic influenza had a greater incidence of fever (100% vs 77.4%; p<0.001), dry cough (95.7% vs 82.7%; p=0.01), and vomiting (26.1% vs 1.9%, p<0.001) as compared with patients infected during the first wave. The rate of bacterial pneumonia was 18.8% (13/69) during the peak pandemic period and 12.5% (3/24, p=0.754) during the postpandemic period. None of the postpandemic influenza subjects' intensive care unit stays were due to pneumonia. The hospitalized early 2009 H1N1 pandemic cases and postpandemic cases were milder compared with those at the peak of pandemic activity.
authors.affiliation: Department of Infectious, Chest Diseases Dermatovenereology and Allergology, Vilnius University, Lithuania , Vilnius, LT-08117.
authors.forename: Arvydas
authors.initials: A
authors.lastname: Ambrozaitis
authors.affiliation: Department of Infectious, Chest Diseases Dermatovenereology and Allergology, Vilnius University, Lithuania , Vilnius, LT-08117.
authors.forename: Daiva
authors.initials: D
authors.lastname: Radzišauskienė
authors.affiliation: Public Health Institute, Vilnius University, Lithuania , Vilnius, LT-03101.
authors.forename: Kęstutis
authors.initials: K
authors.lastname: Žagminas
authors.affiliation: Public Health Institute, Vilnius University, Lithuania , Vilnius, LT-03101.
authors.forename: Nerija
authors.initials: N
authors.lastname: Kuprevičienė
authors.affiliation: University Hospitals-Case Medical Center and Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America and Warren Alpert Medical School of Brown University.
authors.forename: Stefan
authors.initials: S
authors.lastname: Gravenstein
authors.affiliation: Department of Infectious, Chest Diseases Dermatovenereology and Allergology, Vilnius University, Lithuania , Vilnius, LT-08117.
authors.forename: Ligita
authors.initials: L
authors.lastname: Jančorienė
keywords: Complications; Epidemiological characteristics; Influenza A(H1N1)pdm09; postpandemic influenza