The World Health Organization plans to start shipping swine flu vaccine to Azerbaijan, Afghanistan and Mongolia in the next few weeks, flu chief Keiji Fukuda said Thursday.

Another 32 developing countries are in line to get the vaccine soon. The UN health agency has prioritized sending the shots to Northern Hemisphere countries first, which are being hit harder by swine flu than countries in the Southern Hemisphere.

The agency had hoped to send the vaccine earlier, but the effort has been delayed by manufacturing problems and bureaucracy.

When WHO declared swine flu to be a pandemic, or global outbreak, in June, it warned the virus could have a devastating impact in countries across Africa with high numbers of people with health problems like malnutrition, AIDS, and malaria.

Most people who catch swine flu only have mild symptoms like a fever or cough and recover without needing medical treatment.

WHO has a stockpile of about 180 million swine flu shots, donated by six drug makers and a dozen countries.

Countries hoping to get swine flu vaccine from WHO must formally ask for it, agree to certain terms and conditions on how it will be used, and develop a plan to make sure the right people — like health workers and those with underlying health problems — get it first.

WHO is hoping to send enough swine flu vaccine to cover about 10 per cent of populations in poor countries. Countries likely won't start vaccinating their populations until a few weeks after they receive the vaccine, but Fukuda said it wasn't too late to ship the vaccine — even though swine flu appears to have peaked in several Northern Hemisphere countries.

"This is a virus that we don't expect to suddenly disappear," Fukuda said, adding WHO expected the virus to keep circulating for the next few years.

Fukuda said it was "premature" to consider whether the pandemic might be on the decline, and that WHO would consult experts before making such a declaration. He said flu activity this year had peaked "extraordinarily early" and warned there were still several months of winter to come.