The main antiviral drug used to treat the most-common form of flu in the U.S., is ineffective against most cases tested so far this flu season, according to a new study published in the Journal of the American Medical Association.
Some 264 of 268 samples of the H1N1 strain taken this flu season were resistant to Tamiflu, also known as oseltamivir. Only 19 percent of the H1N1 viruses tested during the previous flu season were resistant to Tamiflu.
Tamiflu is an antiviral drug made by Roche AG designed to both treat and prevent influenza A and B. It is used in more than 60 countries, including Japan and the U.S.
Scientists say the resistance does not appear to be caused by over-prescription of the drug, but the result of a natural mutation. But it is complicating matters for physicians trying to ease patients’ symptoms.
While alternative antiviral drugs come with their own resistance and side effects, Tamiflu is the best and perhaps only truly useful drug that can be used against influenza right now, Pekosz said.
Antiviral drugs can reduce the severity of the flu and shorten its duration if prescribed within the first 48 hours of the onset of symptoms.
But health officials say the increasing resistance to antiviral drugs makes flu prevention that much more important. “Vaccination… is the best prevention for illness due to influenza infection,” says Dr. Nila J. Dharan, of the CDC and an author of the study.
The flu season has not peaked warns public health officials. Vaccines are still available and provide protection within two weeks.
“We have been seeing more cases in late January or early February, not only of those who are getting formal flu diagnoses, but also those who are coming in with influenza-like illnesses,” said Dr. John M. Cmar, an infectious disease specialist at Sinai Hospital in Baltimore.
The most recent estimates from the CDC show that nine children have died from the flu this year. Eighty-four children died from the flu in 2008.
An estimated 30,000 people die each year from the flu. And about 200,000 people are hospitalized. The CDC recommends every child between the ages of 2 and 18 get a flu shot, as well as anyone over the age of 65 and those with weakened immune systems. #