Common Flu Strain Resistant to Popular Anti...(H5N1) Imperato said. On the face of ...),Health

"On the face of it, the emergence of resistance in the presence of limited drug use would seem unusual," Imperato said. "However, in many areas of the world, there is significant Tamiflu use for upper respiratory infections. It is believed that minor mutations in the H1N1 virus can in effect block the action of Tamiflu," he said.

It is important to note that no H1N1 influenza resistance to Relenza has developed, Imperato said. "This is the other drug in the neuraminidase group used to prevent and treat influenza," he said.

Flu usually causes about 36,000 deaths in the United States each year. Most deaths are among the elderly, very young or those with medical conditions such as asthma or heart disease. Pneumonia resulting from flu is usually the fatal complication.

More information

For more on the flu, visit the U.S. Centers for Disease Control and Prevention.

SOURCES: Joseph Bresee, M.D., chief, Epidemiology and Prevention Branch Influenza Division, U.S. Centers for Disease Control and Prevention, Atlanta; Pascal James Imperato, M.D., M.P.H., Dean and Distinguished Service Professor, Graduate Program in Public Health, SUNY Downstate Medical Center, New York City