More than 20 world leaders have called for a new global treaty to help the world better prepare for future pandemics.
Leaders including Britain’s Boris Johnson, Germany’s Angela Merkel, France's Emmanuel Macron, South Korea's Moon Jae-in and South Africa's Cyril Ramaphosa called for universal access to vaccines.
They said the Covid-19 crisis had exposed the world’s “weaknesses and divisions”, while another pandemic was a matter of “not if, but when”.
Dr Tedros Adhanom Ghebreyesus, the head of the World Health Organisation, said the world could not afford to wait until the pandemic was over to start planning for the next one.
More than 2.8 million have died from Covid-19 worldwide, Johns Hopkins University figures show. About 27 million have been infected by the virus first detected in China in late 2019.
The spread of the virus has led to blame being traded between capitals and accusations of rich nations hoarding vaccines as economies around the world took a battering.
The call came as the UK government signed a new deal with GlaxoSmithKline to bottle 60 million vaccine doses at a factory in north-east England.
UK's Business Secretary Kwasi Kwarteng said on Tuesday that Britain would only share vaccines when there was excess supply.
“Our focus has to be to try and keep Britain safe,” he told Sky News.
“If there are surplus vaccines, then we can share them, but there is not a surplus at the moment.”
The 24 signatories of Tuesday's letter, In an article published in newspapers around the world, said that a treaty similar to that signed in the wake of the Second World War was needed to build cross-border co-operation.
"We believe that nations should work together towards a new international treaty for pandemic preparedness and response," the letter said.
"Such a renewed collective commitment would be a milestone in stepping up pandemic preparedness at the highest political level."
The op-ed said the treaty should be aimed at "greatly enhancing international co-operation" on alert systems, data-sharing and research to help track rising threats and the production of vaccines, medicines and protective equipment to tackle diseases.
"Together, we must be better prepared to predict, prevent, detect, assess and effectively respond to pandemics in a highly co-ordinated fashion," the leaders said.
"At a time when Covid-19 has exploited our weaknesses and divisions, we must seize this opportunity and come together as a global community for peaceful co-operation that extends beyond this crisis."
The treaty – first proposed by President of the European Council Charles Michel to the UN last year – would probably be the focus of major international wrangling.
Mr Michel said the Covid-19 outbreak had taught the world the "brutal lesson" that no country or continent on its own could defeat a health emergency.
He said the global community needed to "build a pandemic defence for future generations that extends far beyond today's crisis. For this, we must translate the political will into concrete actions".
Dr Tedros said: “Without an internationally co-ordinated, all of government, all of society, one-health approach to pandemic preparedness and response, we remain vulnerable.
“It (the pandemic) has shown how much we need a universal commitment to basic public health principles as the foundation for our work to prevent, detect and respond to epidemic and pandemic threats.
“The idea behind the proposal for such a treaty is to systematically tackle the gaps exposed by Covid-19.
“The world has come together as never before to take on this crisis.”
On Tuesday, the treaty received the formal backing of the leaders of Fiji, Portugal, Romania, Britain, Rwanda, Kenya, France, Germany, Greece, Korea, Chile, Costa Rica, Albania, South Africa, Trinidad and Tobago, the Netherlands, Tunisia, Senegal, Spain, Norway, Serbia, Indonesia, Ukraine and the WHO.
Leaders from key world powers including the United States, China, Russia and Japan were not among the signatories.
But those who did put their names to the plan said they were "committed to ensuring universal and equitable access to safe, efficacious and affordable vaccines, medicines and diagnostics for this and future pandemics".
"We must be guided by solidarity, fairness, transparency, inclusiveness and equity," they wrote.