Loading...
Concern about pandemic influenza has focused attention on drug resistance in influenza virus strains. Resistance to neuraminidase inhibitors has been noted in influenza A strains but has rarely been documented in influenza B strains. However, an influenza B epidemic in Japan during the 2004–2005 flu season gave investigators the opportunity to check for drug-resistant strains.
The researchers obtained respiratory samples from 422 patients who had been diagnosed with influenza B infection by rapid diagnostic testing. For 74 children, they collected respiratory swabs both before and during oseltamivir therapy. In one child (1.4%), the posttreatment isolate’s IC50 for zanamivir and oseltamivir increased 7.1-fold and 3.9-fold, respectively, comp…