The global production of vaccines for the A/H1N1 flu will be far less than the previous forecast maximum of 4.9 billion doses a year, the World Health Organization (WHO) said on Friday.

WHO spokesman Gregory Hartl told a news briefing in Geneva the previous forecast had been based on all drugmakers producing the new vaccine with full capacity, but drugmakers were still producing vaccines for seasonal flu.

The WHO has said that it's impossible for the world's 6.3 billion people to all be vaccinated against the A/H1N1 flu because of the limited production capacity for vaccines.

It also recommends other preventive and treatment measures, including anti-viral and other drugs, social distancing and personal hygiene.