Flu strains developing resistance to key antiviral drug: WHO

May 12, 2009

Development of a swine flu vaccine was partly triggered by evidence that seasonal influenza strains are developing resistance to antiviral drug Tamiflu, a World Health Organisation expert said Tuesday.

Nikki Shindo said relatively high rates of hospitalisation for in the United States and Mexico "rightly" prompted "because we are also facing the risk of having resistant viruses."

"Last year we have seen widespread evidence of oseltamivir resistance in seasonal influenza," said the pandemic flu expert at a daily WHO briefing on the outbreak of influenza A(H1N1).

"So given that we have winter in Southern American countries and also the other parts of the southern hemisphere, there will be a risk of having viruses that will be highly resistant to antivirals."

Flu outbreaks are at their most active during winter.

Oseltamivir is the active ingredient in , an antiviral made by Swiss pharmaceutical manufacturer Roche which is at the centre of global precautions -- led by the WHO -- against influenza and a possible pandemic.

Roche said Tuesday it was donating 5.65 million treatment courses of Tamiflu to help the WHO fight the swine flu outbreak and boosted its production capacity for the next five months.

In the absence of an efficient vaccine against influenza A(H1N1) for now, only Tamiflu and , made by , are considered efficient drugs to keep the virus in check.

Data from the United States and Mexico suggested that nine to 10 percent of confirmed cases of swine flu require hospitalisation, Shindo said, adding: "This clearly is different from what we see from seasonal influenza, that's for sure."

However, the WHO is preparing to publish clinical guidance to doctors and nurses on the new A(H1N1) virus this week highlighting the fact that most patients would not require hospitalisation or antiviral therapy, she said.

Shindo also highlighted different approaches to the use of antivirals to treat swine flu on either side of the Atlantic.

While the United States and Mexico tended to confine such treatment for the most vulnerable, such as those with chronic illness or pregnant women, European countries resorted to the drugs more readily.

"The European countries which are mainly importing cases have been using anti-virals very aggressively," Shindo remarked.

Mexico and the United States, where the outbreak was first uncovered last month, together account for nearly 90 percent of the 5,251 cases of the A(H1N1) virus confirmed by the WHO in 30 countries.

However, there were hints this week that the virus might have already been circulating more widely there when it was first uncovered.

Anne Schuchat, the interim deputy director for science and public health at the Centres for Disease Control said the 2,600 confirmed cases in the represented just the tip of the iceberg of actual infections.

The vast majority of people who became ill with the virus tended to recover in the same way as with seasonal flu and probably did not seek laboratory testing, she explained.

Science magazine also released online a study by the WHO Rapid Pandemic Assessment Collaboration, which includes CDC scientists, which estimated that 23,000 people had been infected by the A(H1N1) in Mexico.

(c) 2009 AFP

Explore further: Washington woman's measles death is first in US since 2003

Related Stories

Flu drug advised for pregnant women with swine flu

May 12, 2009

(AP) -- Pregnant women should take prescription flu medicines if they are diagnosed with the new swine flu, health officials said Tuesday. So far, the swine flu has not proven to be much more dangerous than seasonal influenza, ...

Outwitting mutating flu during a pandemic

May 04, 2009

(PhysOrg.com) -- In a global influenza pandemic, small stockpiles of a secondary flu medication - if used early in local outbreaks - could extend the effectiveness of primary drug stockpiles, according to research made available ...

Recommended for you

Washington woman's measles death is first in US since 2003

5 hours ago

Washington state health officials say measles caused the death of a woman from the northwest part of the state in the spring—the first measles death in the U.S. since 2003 and the first in Washington since 1990.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.