If Tamiflu resistance does develop in exposed birds, the affected flu strains will probably be conventional seasonal and avian flu strains, which claim thousands of lives each year, and not H1N1. That’s because H1N1 seems to bypass birds as it spreads among people, notes William Schaffner, chair of preventive medicine at the Vanderbilt University School of Medicine in Nashville, Tenn.

He also notes that U.S. policy is more conservative than Japan’s when it comes to Tamiflu use. Federal guidelines, he says, recommend that “Tamiflu be reserved for treatment of the very sick and anyone who is immunocompromised.”