A study in this week’s Nature shows that the H5N1 strain of bird flu seems to be developing drug resistance [wrong link fixed]. This, say the authors, means stockpiles designed to be used in a pandemic need to be made up of more than one drug.

Researchers led by Steve Gamblin, of the National Institute for Medical Research in London, used X-ray crystallography to determine the structure of mutants of H5N1. They found that the drug oseltamivir (Tamiflu) was not very useful against them, but zanamivir (Relenza) was still good. (Needless to say, Relenza’s producer Glaxo is pretty happy.)

“In order not to be outflanked by the virus, it will be necessary to have stocks of both existing drugs,” says Gamblin (BBC). “There is a huge imperative to develop further drugs and it is likely a future pandemic will need to be tackled using a three or four-pronged approach, much as we tackle HIV today.”

This may be bad news for countries like Australia, which has stockpiled 6.9 million courses of Tamiflu compared with just 1.8 million courses of Relenza.

“Well it certainly emphasises greatly that relying on a single drug is somewhat foolhardy when there is more than one drug available, and certainly when these drugs are complementary in terms of one being effective against the viruses that are resistant to another drug,” Alan Hay, another author on the paper, told ABC’s AM radio programme (transcript).

According to Reuters Tamiflu had sales of $1.8 billion in 2007 versus Relenza’s $510 million.

Other bird flu news

Indonesia will share genetic information on the virus in its country, “18 months after strategic adviser Peter Bogner and 77 influential scientists and health experts wrote a letter to Nature magazine calling for information about bird flu to be shared more quickly and openly” (AP).

South Korea is building a plant to mass produce a vaccine in the event of a pandemic (Xinhua).

All poultry in Seoul have been killed after an outbreak of bird flu (AP).

The Chosun Ilbo asks “Has Bird Flu Made a Permanent Home in Korea?”

Image: electron micrograph of H5N1 (brown) grown in MDCK cells (green) / CDC/ Courtesy of Cynthia Goldsmith, Jacqueline Katz, and Sherif R. Zaki