Tamiflu resistance seen in flu viruses, says ECDC

Preliminary results from testing conducted by the European Center for Disease Control and Prevention (ECDC) indicate that some strains of the influenza A circulating in Europe this season are unaffected by Roche's antiviral Tamiflu (oseltamivir). Of the 148 H1N1 viral variants isolated between November and December of 2007 by the European Union's VIRGIL network, 19 have shown some degree of resistance.

The majority of the positive samples, 12 of the 19, are derived from the 16 isolates submitted by Norwegian authorities, indicating that viruses circulating in the country have a high degree of resistance to Tamiflu.

Senior influenza experts told The Canadian Press that, because none of the positive samples were from patients that had received Tamiflu, the findings are "the first clear evidence that influenza A (H1N1) virus with the H274Y mutation [which allows that to resist Tamiflu] can readily transmit between individuals."