Comparison of the clinical symptoms and the effectiveness of neuraminidase inhibitors for patients with pandemic influenza H1N1 2009 or seasonal H1N1 influenza in the 2007–2008 and 2008–2009 seasons

Abstract The clinical symptoms and effectiveness of neuraminidase inhibitors (NAI) have not been adequately compared among pandemic H1N1 2009 patients, seasonal H1N1 patients, and patients with H1N1 with the H275Y mutation. The data of 68 seasonal H1N1 patients in 2007–2008, 193 seasonal H1N1 patients in 2008–2009, and 361 pandemic H1N1 2009 patients diagnosed by PCR who received an NAI were analyzed. The duration of fever (body temperature ≥37.5ºC) after the first dose of NAI and from onset was calculated. The H275Y neuraminidase mutation status was determined for 166 patients. Significantly lower mean age (18.4 ± 13.2 years) and a higher percentage of teenagers (53.7%) were found for pandemic 2009 influenza than for seasonal influenza ( P