The World Health Organization (WHO) urged pharmaceutical companies to donate at least 10 per cent of their H1N1 pandemic swine flu vaccine to poor countries, or at least offer them lower prices, to ensure that they don't get left out as it is likely that demand will outstrip capacity to supply in the months ahead.

Six out of 30 major drug companies have agreed to do so. Their chiefs met with UN Secretary General Ban Ki-moon and WHO Director-General Dr Margaret Chan in Geneva where health ministers from nearly 200 member countries are currently attending the 62nd World Health Assembly.

Ban said there was still a need for vigilance over the H1N1 virus:

"We may be in a grace period with H1N1 but we are still in the danger zone," said Ban, as reported by the BBC.

By grace period Ban was referring to Chan's opening speech on Monday where she used the phrase "grace period" to refer to the fact that the virus has not yet reached developing countries, giving us time to help them prepare for it.

She said if and when the virus reaches developing countries they were likely to be more vulnerable and experience a higher proportion of serious cases and deaths than we have seen so far because their populations carried 80 per cent of the world's burden of chronic diseaeses such as HIV/AIDS, malaria and tuberculosis.

According to the WHO, there are now nearly 10,000 confirmed cases of new H1N1 swine flu in 40 countries, including 79 deaths, most of them in Mexico where the outbreak was first reported.

Many rich countries such as Britain, Canada, Denmark, France and Switzerland have already agreed contracts with drug companies to supply millions of doses of pandemic vaccines as they come off the production line.

However, Chan said the drug companies have given "very serious commitments" to helping developing countries when she met them on Tuesday.

Ban called for global solidarity in confronting the new H1N1 virus, and said it was important for the drug companies and governments to work together to lessen the impact.

Solidarity "must mean that all have access to drugs and vaccines," said Ban, according to a report by the Associated Press.

"Partnerships with the private sector are absolutely vital," he added.

But the manufacturers said it will take months to produce large quantities of the vaccine, and production cannot start before mid-July, which is weeks later than anticipated.

One of the reasons that the manufacturers will not be able to start making vaccine until mid-July is because the new H1N1 strain is proving very slow to grow in laboratories, said the WHO.

Eric Althoff, a spokesman for Novartis AG, a large Swiss drug company said:

"I don't think that all of the answers are there yet."

GlaxoSmithKline PLC, which is British based, said they would donate 50 million doses and offer more at discount prices.

According to the AP report, another drug company with much less capacity said they would share half their doses. The WHO did not say which company as the deal was still in negotiation.

And other smaller companies also said they would offer 10 per cent of their vaccine doses to the UN at lower prices.

There is also confusion about how many doses will be available and by when. Some experts say 5 billion doses should be ready within a year of starting full scale production, while others say that is too optimistic.

David Fedson, a vaccine expert who used to be a medical professor at the University of Virginia, said we need to be cautious about predictions, and just "go forward with production as quickly as possible".

Another area of debate is whether to dedicate all vaccine making capacity to the new H1N1 strain and not develop any seasonal flu vaccine for the coming season. Seasonal flu kills up to half a million people worldwide every year.

The United States has not reserved any swine flu vaccine capacity, and is working to enhance seasonal flu production capacity so that it can switch over to pandemic flu vaccine if necessary.