Two Vietnamese people died of bird flu this year after the H5N1 virus developed resistance to Tamiflu, the main drug used to treat the disease, say researchers.
The findings, reported today (22 December) in the New England Journal of Medicine, raise doubts about plans to rely on Tamiflu in the event of a global flu pandemic.
Many scientists say it is almost inevitable that the bird flu virus will mutate into a form that spreads easily between people, potentially killing millions.
Governments are stockpiling Tamiflu, but the news from
In August, researchers suggested in The Lancet that H5N1 would be less likely to become resistant to zanamivir — also called Relenza — than to Tamiflu (see Bird flu: in favour of contingency plans).
The call was repeated in October, when research in Nature described Tamiflu-resistant H5N1 found in a Vietnamese girl. She had been given a low dose of the drug after her brother fell ill, and was later infected herself (see Tamiflu-resistant bird flu found in
In the two latest cases, however, it appears that the virus rapidly developed resistance to the drug in patients as they were being treated for their infections.
The team behind these findings — led by Jeremy Farrar of the Oxford University Clinical Research Unit at the Hospital For Tropical Diseases in
They add that other drugs should be considered for use alongside Tamiflu.
H5N1 has so far killed 71 people in