Switzerland has ordered enough bird flu vaccine to protect its entire population in the event of a pandemic, it was announced on Wednesday.
The government said this amounted to eight million doses of a new pre-pandemic vaccine made by Anglo-American firm GlaxoSmithKline. The cost is expected to be SFr180 million ($142 million).
Supply and stockpiling of the medication is expected to take place from January 2007, said a statement. The cost of the delivery will also have to be approved by parliament.
"If needed, it will therefore be possible to offer a first immunisation to the whole of the [7.4 million] population," said the government.
"This vaccination will be voluntary and will only be administered once its effect against a pandemic virus has been proven."
Advanced development efforts to create an effective H5N1 influenza vaccine are currently based on an H5N1 virus isolated from a Vietnamese patient infected by a chicken in 2004.
Since there is no pandemic among humans, this vaccine is referred to as a pre-pandemic H5N1 vaccine. The pre-pandemic vaccine helps prepare the human immune system against the threat of a human pandemic.
Should a pandemic virus emerge that can be easily transmitted among humans, a vaccine based on that specific strain will have to be developed.
The government has therefore concluded a further agreement with Glaxo for 7.5 million doses of a pandemic vaccine should the need arise.
The immunisation programme, part of the government's national bird flu plan, will be carried out by the authorities concerned and the cantons.
The government's bird flu action plan, finalised in August, proposes detailed guidelines, plans and responses in the event of an outbreak of the virus in the country.
Experts say that although cross-infection of the virus to humans is rare, there have been almost 150 deaths from the illness in humans, mainly in Asia.
Switzerland has already built up a stock of the anti-viral drug Tamiflu to treat more than two million people and protect health workers.
The country has also continued to protect its borders from a possible outbreak of the virus. The latest measures include locking up poultry kept within one kilometre of major Swiss lakes and rivers.
The restrictions are designed to prevent domestic flocks from coming into contact with migratory birds infected with the H5N1 virus and will remain in place until April 30 next year.
Thirty-two dead wild birds were found with the H5N1 virus in Switzerland in February and March, mainly around lakes. But no new cases have been detected in Switzerland since April.
swissinfo with agencies
According to the latest Swiss government plan, 1.85 million people in the country could become infected with bird flu if the virus is able to pass from human to human.
In that event, 46,000 people would be admitted to hospital and around 7,400 people would die.
According to the government, such a pandemic would cost an estimated SFr2.3 billion.
According to latest WHO figures, there have been 253 cases of human bird flu in ten countries since 2003, with 148 deaths.
Most fatalities have occurred when humans have been in close contact with infected poultry.
Health experts fear the H5N1 virus will eventually mutate into a form easily transmissible among humans.
No cases of human bird flu have been reported in Switzerland.