Science / Medicine : Caution Urged on Anti-Viral Drug

Strains of influenza-A virus resistant to a new anti-viral drug develop rapidly and are apparently transmitted to healthy people who are taking the drug to guard against the viral disease, researchers from the University of Virginia have found. The new study assessed the ability of the drug rimantadine to prevent the transmission of the highly contagious, sometimes fatal disease in households where one family member already had influenza.

Drug-resistant strains of the virus were found a third of the influenza patients and those strains were also found in some previously healthy family members who developed symptoms, Dr. Frederick Hayden reported in the New England Journal of Medicine.

The findings suggest that using the drug to control an outbreak of influenza may result in the transmission of drug-resistant strains. That could be a problem in places like hospital wards, Hayden said.

Until more information is available, he said it may not be advisable to use the drug to treat influenza patients who are in close contact with high-risk individuals. Influenza-A affects about 10% of the U.S. population every year, killing 10,000 to 30,000 people.