# 2610
It is a truism in science that the longer we look, the more we learn.
Four years ago, when the first oseltamivir-resistant influenza studies were conducted on ferrets, scientists were heartened to discover that most resistant strains showed compromised biological fitness in the laboratory.
In other words, they did not seem to be easily transmitted. And that gave hope that the mutation that conferred Tamiflu-resistance also made it a dead-end virus.
Today, of course, we know that those early hopes were based on insufficient data. Tamiflu resistant H1N1 viruses have spread globally over the past year, and now have been found in nearly every country that is testing for it.
Among the H1N1 viruses (H3N2 are still sensitive to Tamiflu), in some countries, the percentage of resistant samples is approaching 100%.
These resistant viruses are obviously just as fit, and transmissible, as the non-resistant variety.
Preliminary data, according to the CDC, had suggested that these resistant strains produced no more severe symptoms than its Tamiflu-sensitive cousin, but now, that assumption is being called into question by a study conducted by Norwegian doctors to be published in the CDC's Journal of Emerging Infectious Diseases.
While this data is preliminary, and based on a very small sampling, it suggests that the Tamiflu resistant H1N1 strain may cause a higher incidence of pneumonia and sinusitis than the regular H1N1 strain.
While the study group was too small to draw immediate conclusions, the authors believe their findings warrant further investigation.
Jason Gale, of Bloomberg News, has the story. Follow the link to read it in its entirety.
Drug-Resistant Flu Linked With Pneumonia, Norwegian Doctors Say
By Jason Gale
Dec. 31 (Bloomberg) -- A drug-resistant influenza strain that has spread globally this year needs further study to gauge its virulence, according to doctors in Norway who found the bug was linked with patients suffering more severe symptoms.
A form of the H1N1 seasonal flu virus that evades Roche Holding AG's Tamiflu appeared more likely to cause pneumonia and sinusitis than the H1N1 strain without the resistance-causing mutation, researchers from the Norwegian Institute of Public Health in Oslo and the U.K.'s Health Protection Agency said.
While ``not a statistically significant finding,'' results of the study, involving fewer than 300 patients, ``warrant further investigation,'' the authors said. The study was released online today ahead of publication in the February edition of Emerging Infectious Diseases by the U.S. Centers for Disease Control and Prevention.
Tamiflu-evading influenza has been reported in 50 countries on six continents since widespread resistance to the bestselling antiviral was first reported to the World Health Organization by Norway in January. Its emergence prompted doctors to consider other medicines, such as GlaxoSmithKline Plc's Relenza, to fight a disease the WHO estimates causes 250,000 to 500,000 deaths annually.
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