Bringing science and development together through news and analysis

  • Tamiflu-resistant bird flu found in Vietnam


Researchers have found a strain of bird flu that can resist Tamiflu, the drug that governments and the World Health Organization are stockpiling in preparation for a widely predicted flu pandemic.

The scientists say health authorities should consider stocking up on more than one anti-flu drug.

The Vietnamese and Japanese researchers, led by Yoshihiro Kawaoka of the University of Tokyo, will publish their findings in Nature on Thursday (20 October).

They isolated the drug-resistant H5N1 virus from a 14-year-old Vietnamese girl.

Most of the virus strains found in her blood were resistant to oseltamivir, the flu drug sold commercially as Tamiflu. This resistance was the result of a single genetic mutation in one of the virus's eight proteins.

"We've been watching for this change [in the virus]," Kawaoka says. "This is the first, but we will see others. There's no question about it."

The researchers acknowledge that their findings are based on a single patient, but say the results suggest, "it might be useful to stockpile zanamivir as well as oseltamivir in the event of an H5N1 influenza pandemic".

It is not the first time flu experts have advised governments to stockpile zanamivir, whose trade name is Relenza (see 'Bird flu: in favour of contingency plans').

In August, Kenneth Tsang and colleagues suggested in The Lancet that H5N1, which has killed 60 people in Asia, would be less likely to become resistant to zanamivir than to oseltamivir.

Kawaoka calls oseltamivir the "first line of defence. It is the drug many countries are stockpiling, and the plan is to rely heavily on it."

It is widely accepted that the global flu pandemic experts have been predicting for more than a year could ensue if H5N1 became able to spread from person to person (see Time to prepare for bird flu pandemic 'running out').

Kawaoka and colleagues say that, as far as they could tell, the Vietnamese patient had no direct contact with poultry. She had, however, taken care of her 21-year-old brother while he was infected with H5N1.

So far, the World Health Organization has not confirmed a single case of H5N1 being transmitted between people.

Last year, researchers suggested that a Thai woman might have been infected with the virus while caring for her infected daughter (see Bird flu deaths raise fears of human spread).

The World Health Organization, however, never confirmed this, or other suspected cases of human-to-human transmission.

Link to full paper in Nature

Reference: Nature 437, 1108 (2005)

We encourage you to republish this article online and in print, it’s free under our creative commons attribution license, but please follow some simple guidelines:
  1. You have to credit our authors.
  2. You have to credit SciDev.Net — where possible include our logo with a link back to the original article.
  3. You can simply run the first few lines of the article and then add: “Read the full article on SciDev.Net” containing a link back to the original article.
  4. If you want to also take images published in this story you will need to confirm with the original source if you're licensed to use them.
  5. The easiest way to get the article on your site is to embed the code below.
For more information view our media page and republishing guidelines.