A widespread strain of the influenza virus is proving to be resistant to a common treatment, Time reports. The H1N1 virus, a subtype of influenza A (not to be confused with H5N1, the avian or bird flu) has shown rates of resistance of up to 10% in Europe, Canada, and the US for the drug oseltamivir, sold as Tamiflu.
Health officials said the resistance is not much to worry about. "Influenza A has been circulating for many years," said one. "It's not likely to cause a pandemic." What’s puzzling is the development of resistance. Norway, which doesn’t generally prescribe Tamiflu, saw a 75% resistance rate, but Japan, where Tamiflu use is common, has just a 3% resistance rate.