Increased Mortality in Seasonal H3N2 Patients Compared with those with Pandemic 2009 H1N1 in Taiwan, 2009-2010.

Shi-Yu Huang, Wen-Chi Huang, Yi-Chun Chen, Ching-Yen Tsai, Ing-Kit Lee

Research output: Contribution to journalJournal Article peer-review

5 Scopus citations


We conducted a retrospective study to compare clinical and laboratory findings between 1) severe influenza A and mild influenza A and 2) pandemic 2009 H1N1 (pdm09 A/H1) and seasonal H3N2 (A/H3) from 2009 to 2010. A total of 526 (mean age, 13.6 years; 447 pdm09 A/H1, 79 seasonal A/H3) patients were included, 41 (7.8%) with severe influenza (mean age, 28.1 years; 26 pdm09 A/H1, 15 seasonal A/H3). Influenza-associated complications were pneumonia (75.6%), meningoencephalitis (14.6%), acute kidney injury (14.6%), and acute respiratory distress syndrome (12.2%). Patients with seasonal A/H3 were significantly less likely to experience sore throat (P < 0.001), malaise (P < 0.001), and muscle pain (P < 0.001); they were significantly more likely to have hypertension (P < 0.001), diabetes mellitus (P = 0.001), and chronic obstructive pulmonary disease (P < 0.001), delayed hospital presentation (P = 0.001), delayed oseltamivir treatment (P < 0.001), and higher inhospital mortality (P = 0.02) than patients with pdm09 A/H1. Further comparison between severe pdm09 A/H1 and severe seasonal A/H3 revealed that severe seasonal A/H3 patients (median age, 71 years) were significantly older than patients with severe pdm09 A/H1 (median age, 7 years) (P < 0.001). Comparison between severe influenza and mild influenza, regardless of influenza A subtypes, by multivariate analysis, found that tachypnea (odds ratio [OR] = 44.3, 95% confidence interval [CI] = 15.7-124.6) and delayed oseltamivir therapy ≧ 48 hours after illness onset (OR = 3.7, 95% CI = 1.3-10.5) were independent risk factors for severe influenza. The findings of this study will improve the understanding of the clinical differences between pdm09 A/H1 and seasonal A/H3, and of influenza-associated complications and predictors for severe outcomes that can help to direct clinicians toward the most effective management of influenza patients to reduce the preventable mortality and morbidity.
Original languageAmerican English
Pages (from-to)1945-1951
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number6
StatePublished - 2017


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