An expert panel advising the World Health Organisation on pandemics will review the status of the H1N1 virus later this month or in early June to decide whether the swine flu pandemic is over.

The Emergency Committee is waiting for the onset of winter in the southern hemisphere before making its recommendation, spokesman Gregory Hartl said.

That meant the 15-member independent panel would probably meet at the end of May or in early June, after the WHO's governing World Health Assembly next week, he told a briefing.

'They have to look at the information that exists at that time on the activity of the H1N1 virus,' Hartl said.

The WHO's guidance on whether a disease constitutes a pandemic determines how its 193 member governments handle an outbreak, including stockpiling vaccines and antivirals.

The United Nations body has been accused of exaggerating the dangers of the H1N1 outbreak, which was declared a full pandemic in June 2009 after dominating last year's health assembly.

The current virus appears to have been less severe than the two previous influenza pandemics in 1957 and 1968, which killed about 2 million and 1 million people respectively, with most victims suffering only mild symptoms.

Confirmed deaths from H1N1 since the outbreak emerged in April last year number at least 18,000, but it will be a few years before the real -- much higher -- figure is known.

John Mackenzie, who chairs the emergency committee and is the only one of its 15 members to have been publicly identified, said last month that the current pandemic was as severe as the two previous ones and remained a threat.

Members' identities are kept secret to protect them from pressure from drugs companies or other interest groups.

Hartl said the committee was likely to have three options: conclude that the pandemic was still in force and retain the WHO's current phase 6 on its 6-level pandemic scale; state that the pandemic had moved into a transitional 'post-peak' phase; or declare that the pandemic had passed. – Reuters