The world must study the wreckage of Covid-19 and say "never again" by striking a pandemic preparedness treaty, the WHO said Monday as countries gathered to build a new accord.

World Health Organization director-general Tedros Adhanom Ghebreyesus said another disastrous pandemic was bound to happen unless countries showed the resolve to strengthen global defenses.

Nations are meeting in Geneva from Monday to Wednesday to discuss an international agreement setting out how to handle the next pandemic -- which experts fear is only a matter of time.

The gathering comes with the planet still besieged by Covid-19, nearly two years on from the first recorded cases, and now shaken by Omicron, the new Covid variant of concern.

WHO member states reached a consensus Sunday on kick-starting the process towards a pandemic treaty.

The draft decision was secured after countries agreed to compromise -- notably, the United States, which is luke-warm on whether the outcome needs to be a legally-binding treaty.

The decision should be formalized on Wednesday.

Shadow of Omicron 

"The emergence of the highly-mutated Omicron variant underlines just how perilous and precarious our situation is," Tedros told world leaders at the start of the three-day gathering.

"Omicron demonstrates just why the world needs a new accord on pandemics.

"Omicron's very emergence is another reminder that although many of us might think we're done with Covid-19, it's not done with us.

"It will all happen again unless you, the nations of the world, can come together to say with one voice: never again."

This meeting of the World Health Assembly -- the WHO's decision-making body comprising all 194 member states -- is an unprecedented special session on how to handle the next pandemic.

It should thrash out how far countries are prepared to go towards legally-binding commitments on topics such as equitable vaccine distribution, knowledge-sharing, financing and oversight structures.

The final outcome of the process should come into force in 2024.

Chilean President Sebastian Pinera said the world was unprepared for Covid-19 and "for that weakness, we all paid a great price.

"Steps must be taken to ensure that this will not happen again, that when the next pandemic comes, and it will come, it will find us better prepared," he said. 

Kazakhstan's President Kassym-Jomart Tokayev stressed: "We need to close the gaps that made us vulnerable to the virus in the first place." 

Make history 

The draft decision says WHO member states agree to establish an intergovernmental negotiating body "to draft and negotiate a WHO convention, agreement or another international instrument on pandemic prevention, preparedness and response".

The body's first meeting must be no later than March 1 next year to elect two co-chairs and four vice-chairs.

A progress report will be presented at the regular World Health Assembly annual gathering in 2023, with the final outcome presented for consideration at the 2024 WHA.

European Council President Charles Michel, who first got the ball rolling on a pandemic treaty, said: "I hope we will make history. The situation in the world demands it.

"Yesterday's informal agreement is a huge step, and now it's time to capitalize on this momentum to make the world a safer place."

German Chancellor Angela Merkel called for reform of how countries fund the WHO so it can react more flexibly to crises. 

"Measures for better prevention and response to pandemics should be laid down in a pandemic treaty, binding under international law," she said. 

Swiss Health Minister Alain Berset said the world needed to take immediate, bold action, as he called for a legally-binding instrument.

"The issues at stake are too important. We don't have the right to fail," he said.