By Laura MacInnis and Stephanie Nebehay
GENEVA (Reuters) - The H1N1 flu strain has not yet taken hold outside the Americas region, but the outbreak is serious and requires close monitoring, a World Health Organisation official said on Thursday.
Keiji Fukuda, acting WHO assistant director-general, said the United Nations agency was maintaining its pandemic alert at the second-highest notch of 5 despite the virus having caused 6,497 infections in 33 countries.
"If we see changes in the severity we will let the world know about that," he told a news conference. "This is an event that is serious and that requires close monitoring."
The Phase 5 designation means a pandemic is imminent.
Leading vaccine makers including GlaxoSmithKline, Sanofi-Aventis, Novartis and Baxter International are awaiting guidance from the WHO about whether to start manufacturing vaccines for a pandemic instead of seasonal flu.
Vaccine experts convened by the WHO on Thursday did not reach a firm conclusion about whether such a switch should take place, or whether the H1N1 strain should be included in the mixture of the seasonal flu jab, Fukuda said.
"There will be additional meetings," he said after that teleconference drawing together pharmaceutical representatives and health officials, which he said ended with "no big decisions, no pronouncements."
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Because seasonal flu kills up to 500,000 people a year, health officials have been calling for the continued production of vaccines for at-risk people including the elderly, pregnant women, and people with other health conditions like asthma.
A WHO medical officer told reporters earlier this week that such groups should also have priority in the distribution of antiviral drugs that have been shown to work against the H1N1 strain, which is a mixture of swine, bird and human viruses.
But Fukuda stressed on Thursday that the WHO did not plan to alter its guidance on when and whether to prescribe antivirals like Roche's Tamiflu or GlaxoSmithKline's Relenza, saying this was at countries' discretion.
"WHO is not making any changes in its recommendations on antivirals," he told the news conference.
The United Nations agency has convened an intergovernmental meeting about the sharing of flu virus samples -- which vaccine makers need to formulate the ingredients of jabs -- at its Geneva headquarters on Friday.
The flu and global needs for antiviral drugs and pandemic vaccines are also expected to dominate next week's World Health Assembly, an annual meeting that will draw top health officials from around the world to Geneva.
According to the latest WHO tally, 65 people have died from infection with the H1N1 virus, which remains most prevalent in North America. Evidence that the flu is spreading in a sustained way in Europe, Asia or elsewhere would cause the WHO to raise the pandemic alert to the top level of 6.
The WHO said Mexico has had 2,446 confirmed cases including 60 deaths. The United States has reported 3,352 confirmed cases including 3 deaths. Canada has 389 confirmed cases and Costa Rica 8 cases, both with one death.
Other countries with confirmed cases but no deaths are Argentina (1), Australia (1), Austria (1), Brazil (8), Britain (71), China (4), Colombia (7), Cuba (1), Denmark (1), El Salvador (4), Finland (2), France (14), Germany (12), Guatemala (3), Ireland (1), Israel (7), Italy (9), Japan (4), Netherlands (3) New Zealand (7), Norway (2), Panama (29), Poland (1), Portugal (1), South Korea (3), Spain (100), Sweden (2), Switzerland (1) and Thailand (2).
(For a WHO map of the spread of cases, go to: http://www.who.int/csr/don/h1n1_20090514_0800.jpg )
(For WHO information on swine flu, go to: http://www.who.int/csr/disease/swineflu/en/index.html )
(Additional reporting by Jonathan Lynn)
