A mutated strain of the H1N1 virus has killed two people and made one person very ill in Norway. Researchers are unsure if the mutated strain is circulating or if it arose spontaneously in each case, but they say they have no reason to suspect that the it has any implication for the effect of the vaccine or antiviral drugs like Tamiflu.
"There is always a concern about flu viruses mutating," says ACSH's Dr. Elizabeth Whelan. "What they are most concerned about in Norway is that the mutation seems to increase the virus' penetration into the lungs, leading to higher risk of fatality."
"Keep in mind that this is only two fatalities," says ACSH's Dr. Gilbert Ross. "They found that these people had a more severe than normal strain, but if you only survey influenza victims who succumbed, you'll typically find that they had more severe cases. That doesn't imply that this mutated strain is taking over. And the causative virus was specifically found to be susceptible to Tamiflu and Relenza."