Thailand, a country on the frontline of the war against Asia’s bird flu, is stockpiling Tamiflu and considering producing a generic version of the antiviral drug, health officials said.

Thailand, the latest country to increase stocks of the drug to meet World Health Organization guidelines for fighting the deadly virus, began limited use of Tamiflu last year on patients suspected of contracting the H5N1 bird flu virus.

“We have started a stockpile of Tamiflu. This is just a backup measure,” senior Health Ministry official Supamit Chunsutiwat told reporters late on Thursday.

Tamiflu, made by Switzerland’s Roche Ag and also known as oseltamivir, has been singled out by the WHO as its drug of choice to protect against bird flu and in case of a human flu pandemic.

The WHO says bird flu - which has killed 47 people in Asia - could mutate into a form that spreads easily between humans and trigger a global pandemic that could kill millions.

Tamiflu belongs to a drug class that blocks the action of viral enzymes. It proved effective in managing an outbreak of the H7N7 avian strain in the Netherlands in 2003, which infected about 1,000 people.

Hong Kong announced plans on Wednesday to beef up its stocks of the drug, and other countries such as France, Britain, New Zealand, Sweden and Canada have also placed significant orders.

But the high cost has prompted Thailand to consider producing its own supply of oseltamivir, said Suwit Wibulpolprasert, a senior adviser on health economics at the Health Ministry.

“Hopefully, if the active ingredient which we are importing from India proves to be good quality, we will be able to produce the drug in an emergency case in six months,” Suwit said.

Thailand, like other developing countries with established pharmaceutical factories, has the right to issue a compulsory license and make generic copies of patented drugs in the event of a medical emergency. It already makes generic anti-AIDS drugs.

Health experts say improving detection and reporting of the virus in countries with poor health care systems is as crucial as stockpiling the drug.

Tamiflu is most effective when taken within two days of the onset of symptoms and Thailand has increased its surveillance and reporting of suspected cases since it reported its first outbreaks in January last year.

But in poor neighboring countries like Cambodia and Vietnam, surveillance systems are still inadequate, due partly to a lack of public awareness.

“You have to give the drug to them in the first 48 hours and this is very challenging. After that, the effectiveness is very low,” said Dr. Somchai Peerapakorn of the WHO office in Bangkok.

“It’s still not a very good tool, but it’s the only tool.”