GENEVA (Reuters) - Southern hemisphere countries struck by H1N1 flu last year are now broadly protected against new infections, the World Health Organisation said on Friday.
In its latest assessment of the virus, the WHO signalled the worst of this year's northern hemisphere flu season may be over for most countries, with sickness levels declining in much of Europe and in North America, where the pandemic first emerged.
The H1N1 virus - declared a global pandemic by the United Nations health agency last June - has killed at least 12,799 people, according to the WHO's toll of lab-confirmed cases.
More than half of the official deaths, at least 6,880, have been in the Americas where the virus has become less active across the board, the WHO said.
Disease activity peaked in October in Mexico, the United States and Canada, with flu infections now below the historical seasonal baseline after a big surge in autumn and early winter.
And in southern hemisphere nations, where H1N1 was prolific last year, the WHO said the flu virus was now spreading less easily among people who were already exposed to it.
"In temperate regions of the southern hemisphere, sporadic cases of pandemic influenza continued to be reported without evidence of sustained community transmission," it said.
"This suggests that the level of population immunity in areas that experienced intense, high-level transmission during a winter season is high enough to prevent sustained transmission from returning during the summer when the virus is less transmissible."
The WHO did not say whether those countries would be better protected for their next winter season, typically when flu viruses spread fastest and easiest.
WHO Director-General Margaret Chan said last week it would take another six to 12 months for the first pandemic in more than 40 years to run its course.
She said pregnant women, young people and those with chronic medical conditions like asthma should continue to take special precautions against the virus for which several companies including GlaxoSmithKline, Novartis and Sanofi-Aventis have created a vaccine.
Mongolia is the first developing country to receive donated H1N1 vaccine doses, with 100,000 doses delivered to the country on Thursday, WHO spokesman Gregory Hartl told a briefing.
Azerbaijan was due to receive 170,000 doses later on Friday.
In all, six drug companies and 14 industrialised countries have pledged nearly 190 million doses for use in 95 developing countries, according to the United Nations agency which requires them to have distribution plans and a regulatory framework in place.