cHeroKee
03-02-2009, 09:12 PM
Flu viruses growing resistant to key weapon Tamiflu
http://i.usatoday.net/news/_photos/2009/03/02/tamiflux.jpg
Tamiflu is a key part of governments'
emergency-response drug stockpiles.
By Steve Sternberg, USA TODAY
Evidence that flu viruses are becoming more resistant to the drug Tamiflu has sown deep concern among doctors who are worried that their best flu treatment is losing its punch.
The spread of resistance also has potentially weakened a pillar of the stockpiles of drugs that will be used to combat global flu outbreaks, doctors say.
BETTER LIFE: Low humidity favors influenza (http://blogs.usatoday.com/betterlife/2009/02/low-humidity-fa.html)
The first in-depth analysis of Tamiflu resistance during last year's flu season found that about 12% of people with one of the three strains that caused the most illness, influenza A/H1N1, were infected with resistant viruses. One in five of last year's patients caught the strain, doctors reported Monday.
This year, Tamiflu resistance in that class of viruses has reached almost 100%, turning the tables on a drug designed to defeat resistance. "They're the most common viruses circulating this year," says flu expert William Schaffner of Vanderbilt University. "There are calls coming in from all over the country to infectious-disease doctors and public health specialists asking them how to proceed."
The evidence of growing resistance prompted the Centers for Disease Control and Prevention in December to alter its treatment recommendations. The CDC now urges doctors to use Tamiflu for patients with influenza B viruses or, when they haven't identified the flu type, with rimantadine, one of two drugs from an older class of flu fighting agents.
Relenza, a close cousin of Tamiflu, is still broadly effective, doctors say, but the drug isn't recommended for children younger than 7, those with asthma and those unable to use an oral inhaler.
Doctors say the rapid spread of Tamiflu resistance underscores the value of vaccination. "That's your best protection," says Alicia Fry of the CDC, who is a leader of the government's Tamiflu resistance working group.
Fry's team tested 1,155 A/H1N1 viruses from 45 states. They found that 142 viruses from 24 states were resistant to Tamiflu, or 12.3%. So far this year, 264 of 268 viruses tested were Tamiflu-resistant, or 98.5%, they report in The Journal of the American Medical Association.
The study provoked immediate concern among those in charge of outbreak preparedness, says Robin Robinson, who directs the emergency-response stockpile for the Department of Health and Human Services. Robinson says experts now are considering whether to change the stockpile to be better prepared to deal with Tamiflu resistance.
http://images.usatoday.com/_common/_images/clear.gifhttp://images.usatoday.com/_common/_images/clear.gif RESISTANT FLU VIRUS
http://i.usatoday.net/life/graphics/2009/0301_flu/0301_flu_resist_map.gif
http://i.usatoday.net/news/_photos/2009/03/02/tamiflux.jpg
Tamiflu is a key part of governments'
emergency-response drug stockpiles.
By Steve Sternberg, USA TODAY
Evidence that flu viruses are becoming more resistant to the drug Tamiflu has sown deep concern among doctors who are worried that their best flu treatment is losing its punch.
The spread of resistance also has potentially weakened a pillar of the stockpiles of drugs that will be used to combat global flu outbreaks, doctors say.
BETTER LIFE: Low humidity favors influenza (http://blogs.usatoday.com/betterlife/2009/02/low-humidity-fa.html)
The first in-depth analysis of Tamiflu resistance during last year's flu season found that about 12% of people with one of the three strains that caused the most illness, influenza A/H1N1, were infected with resistant viruses. One in five of last year's patients caught the strain, doctors reported Monday.
This year, Tamiflu resistance in that class of viruses has reached almost 100%, turning the tables on a drug designed to defeat resistance. "They're the most common viruses circulating this year," says flu expert William Schaffner of Vanderbilt University. "There are calls coming in from all over the country to infectious-disease doctors and public health specialists asking them how to proceed."
The evidence of growing resistance prompted the Centers for Disease Control and Prevention in December to alter its treatment recommendations. The CDC now urges doctors to use Tamiflu for patients with influenza B viruses or, when they haven't identified the flu type, with rimantadine, one of two drugs from an older class of flu fighting agents.
Relenza, a close cousin of Tamiflu, is still broadly effective, doctors say, but the drug isn't recommended for children younger than 7, those with asthma and those unable to use an oral inhaler.
Doctors say the rapid spread of Tamiflu resistance underscores the value of vaccination. "That's your best protection," says Alicia Fry of the CDC, who is a leader of the government's Tamiflu resistance working group.
Fry's team tested 1,155 A/H1N1 viruses from 45 states. They found that 142 viruses from 24 states were resistant to Tamiflu, or 12.3%. So far this year, 264 of 268 viruses tested were Tamiflu-resistant, or 98.5%, they report in The Journal of the American Medical Association.
The study provoked immediate concern among those in charge of outbreak preparedness, says Robin Robinson, who directs the emergency-response stockpile for the Department of Health and Human Services. Robinson says experts now are considering whether to change the stockpile to be better prepared to deal with Tamiflu resistance.
http://images.usatoday.com/_common/_images/clear.gifhttp://images.usatoday.com/_common/_images/clear.gif RESISTANT FLU VIRUS
http://i.usatoday.net/life/graphics/2009/0301_flu/0301_flu_resist_map.gif