GENEVA - THE World Health Organisation warned on Friday against a false sense of security from waning and apparently mild outbreaks of H1N1 flu, saying the worst may not be over.

WHO Director-General Margaret Chan said there remained 'great uncertainty' about the new strain that continues to spread and could pose particular threats in Southeast Asia.

What next if WHO declares flu pandemic? LONDON - THE World Health Organisation has been warning for weeks that swine flu is on the verge of flaring into the first flu pandemic in four decades. Countries are on the lookout for cases, governments are buying anti-virals, and China has quarantined entire hotels full of people connected to cases. ... more SHARING SAMPLES THE WHO chief commended countries with H1N1 infections for their 'timely sharing of samples for risk assessment and making seed vaccine,' saying the starting point for larger production of injections could be ready by the end of this month. Participants are seeking to reach agreement on standards for transparency, trust, and sovereignty related to sample sharing. ... more

But she could not say whether or when the United Nations agency might raise its pandemic alert to the highest level from the current 5 on a scale of 6. The trigger would be if sustained spread was confirmed in communities outside of North America.

'Actually, I am asking myself that question every day,' Dr Chan said in response to a question from Argentina's delegation.

'We are meeting at a time of crisis that could have global implications,' she warned the intergovernmental meeting on pandemic influenza preparedness at WHO's Geneva headquarters.

'This is a virus so evasive that it can quietly and stealthily move into your country without you even realising it.' The two-day meeting is tackling the sensitive issue of virus sharing in exchange for access to vaccines derived from them.

At the height of fears about bird flu, Indonesia had refused to share H5N1 virus samples without guarantees the vaccines would be provided to poorer countries at an affordable price.

The negotiations, begun in November 2007, have taken on fresh urgency with the emergence of the H1N1 virus.

If negotiators reach a draft agreement, it would be brought to the WHO's annual assembly of health ministers, who meet in Geneva next week, for possible adoption.

GlaxoSmithKline, Sanofi-Aventis, Novartis, Baxter International and other drug makers are awaiting WHO guidance about whether to start mass-producing vaccines to fight H1N1, which may force them to cut production of seasonal flu shots. Glaxo said on Friday it had received orders from several governments, including Britain, France, Belgium and Finland, looking to stockpile a pandemic vaccine against the new virus.

Dr Chan said she would make a recommendation soon about the appropriate balance between making the two types of injections. 'We are moving on two tracks to ensure some security for seasonal vaccine and at the same time kick-starting early scientific work for pandemic vaccine,' she told the session. -- REUTERS