Development of a swine flu vaccine was partly triggered by evidence that seasonal influenza strains are developing resistance to Tamiflu, a World Health Organisation expert said Tuesday.
Nikki Shindo said relatively high rates of hospitalisation for swine flu in the United States and Mexico "rightly" prompted vaccine development "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 Tamiflu, an anti-viral made by Swiss pharmacuetical manufacturer Roche which is at the centre of global precautions -- led by the WHO -- against influenza and a possible pandemic.
Data from the United States and Mexico suggests that nine to 10 percent of confirmed cases require hospitalisation, Shindo said, adding: "This clearly different from what we see from seasonal influenza, that's for sure."
However, the WHO is preparing to release clinical guidance to doctors and nurses on the new A(H1N1) virus highlighting the fact that most patients would not require hospitalisation or antiviral therapy, she said.
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AFP 121634 GMT 05 09
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