Differences in clinical manifestations and treatment responses in influenza type A and B in a single hospital during 2013 to 2015

Purpose: We suspect there is a difference in the clinical manifestations and treatment response to antiviral drugs for influenza A and B. This study was conducted to investigate this difference. Methods: We collected information on pediatric patients, infected with the influenza virus, admitted to Dongguk University Ilsan Hospital from October 2013 to May 2015. We investigated the clinical manifestations of influenza and differences in treatment response to oseltamivir treatment for the two types of influenza. Results: A total of 138 patients were included. The mean age was 3.5±4.0 years. When comparing the diseases associated with influenza A and B, croup (19.2% vs. 1.7%, P=0.001) was more common with influenza A infection. Myositis (0% vs. 6.7%, P=0.021) and gastroenteritis (29.5% vs. 46.7%, P=0.038) were more common with influenza B infection. When comparing the total fever duration from the start of oseltamivir administration, patients treated with oseltamivir within 2 days of fever had the shortest duration. Among the patients treated with oseltamivir, the duration of fever, after the start of oseltamivir treatment, for was shorter for influenza A infection than for influenza B infection (16.0±19.1 hours vs. 28.9±27.9 hours, P=0.006). Conclusions: There appear to be differences in the accompanying diseases and antiviral medication responses between the two types of influenza. It is important to administer oseltamivir within 2 days of fever.