This is the VOA Special English Health Report.

　　Evidence is increasing that common influenza viruses are becoming resistant to the main drug used to treat them. The drug is oseltamivir, also known as Tamiflu.

　　The most common seasonal flu virus found in the United States this year is type A(H1N1). During the last flu season, twelve percent of H1N1 viruses tested in the United States were resistant to Tamiflu. This year, researchers at the Centers for Disease Control and Prevention say resistance is close to one hundred percent. Still, they say early reports show that flu activity has been low so far this year.

　　The research team is reporting its findings in the Journal of the American Medical Association. Alicia Fry led the team. Doctor Fry says it is better to prevent the flu than to have to treat it. And the best form of prevention, she says, is getting vaccinated each year against influenza.

　　Viruses change, or mutate, so flu vaccines must be reformulated each year to target the most common threats.

　　But last week, two teams working independently reported a discovery that could help lead to a universal flu vaccine. The hope is to develop a vaccine that could give lifelong protection against a majority of flu viruses, including bird flu.

　　The scientists identified a protein that inactivates the flu virus before it can mutate.

　　One team used an antibody found in blood donated by an individual. Scientist Ian Wilson at the Scripps Research Institute in California says the antibodies proved highly effective in laboratory mice exposed to deadly levels of virus. He says they gave complete protection if administered immediately and up to fifty percent protection if administered up to five days later.

　　The researchers say many, if not all, people likely have these antibodies but do not always produce or use them efficiently.

　　The study is in the journal Science.

　　The findings appeared just days after another team reported its findings in the journal Nature Structural and Molecular Biology. That team used almost the same methods but worked with engineered antibodies.

　　Wayne Marasco of the Dana-Farber Cancer Institute in Massachusetts was the lead author of that study. He says identifying human antibodies that will stop the ability of the virus to reinvent itself is the first step. Next comes using them to develop drugs to fight and treat influenza. And that, he says, could require at least three more years of research to reach the point of testing in people.

　　And that's the VOA Special English Health Report, written by Caty Weaver. I'm Mario Ritter.