Duration of fever and PA/I38X-substituted virus emergence in patients treated with baloxavir in the 2018-2019 influenza season.

Duration of fever and virus persistence after baloxavir administration were investigated in 81 outpatients, 16 with A(H1N1)pdm09 and 65 with A(H3N2) in the Japanese 2018-2019 influenza season. Only eight cases of A(H3N2) viruses were detected post-dose. PA/I38T-substituted viruses were detected in four (6.

Persistence of pandemic influenza H1N1 virus in young patients after oseltamivir therapy in the 2009-2010 season: a comparison with seasonal H1N1 with or without H275Y mutation.

Comparison of the viral persistence of pandemic H1N1 (H1N1pdm) and seasonal H1N1 with or without H275Y mutation after oseltamivir therapy has not been adequately done. Virus was isolated before and on days 4-6 from the start of oseltamivir treatment for 158 cases of seasonal (2007-2008 and 2008-2009 seasons) or pandemic (2009-2010 season) H1N1 influenza. Sequence analysis was done for each season and NA inhibition assay (IC(50)) was done in the 2009-2010 season.

Clinical effectiveness of oseltamivir for influenza A(H1N1) virus with H274Y neuraminidase mutation.

Objective: To evaluate the clinical effectiveness of oseltamivir therapy started within 48h of the onset for influenza A(H1N1) virus with H274Y neuraminidase (NA) mutation.

Methods: Virus was isolated before and four to six days after starting oseltamivir treatment from 73 outpatients with influenza A(H1N1) virus in the 2007-2008 and 2008-2009 seasons. NA inhibition assays (IC(50)) and sequence analyses were done using influenza viruses isolated from these patients.