Prime Minister Boris Johnson has joined more than 20 world leaders in calling for a new global settlement to help the world prepare for future pandemics.
In a newspaper article the leaders, including the German chancellor and French president, said Covid posed the biggest challenge since World War Two.
The pandemic has shown “nobody is safe until everyone is safe”, they said.
Business Secretary Kwasi Kwarteng said the UK would need a surplus of vaccines before it could export supplies.
Writing in the Daily Telegraph and publications such as Le Monde in France and El Pais in Spain, the 24 leaders argue that a treaty similar to that reached in the wake of World War Two is needed to build cross-border cooperation.
The signatories, who include the head of the World Health Organization, Dr Tedros Adhanom Ghebreyesus, said: “At that time, following the devastation of two world wars, political leaders came together to forge the multilateral system.
“The aims were clear: To bring countries together, to dispel the temptations of isolationism and nationalism, and to address the challenges that could only be achieved together in the spirit of solidarity and co-operation – namely peace, prosperity, health and security.”
France’s President Emmanuel Macron, German Chancellor Angela Merkel and the other leaders said that in the same spirit, countries must now “be better prepared to predict, prevent, detect, assess and effectively respond to pandemics in a highly co-ordinated fashion”.
A new treaty would help to establish better systems for alerting people about potential pandemics, they said, while also improving the sharing of data and distribution of vaccines and personal protective equipment.
“There will be other pandemics and other major health emergencies. No single government or multilateral agency can address this threat alone. The question is not if, but when.
“The Covid-19 pandemic has been a stark and painful reminder that nobody is safe until everyone is safe.”
The letter added: “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.”
Dr David Nabarro, a special envoy on Covid-19 for the WHO, told BBC Radio 4’s Today programme that without “some kind of special action, the world as a whole will not be vaccinated until well into 2022”.
“During that time all sorts of problems with variants will emerge, and so all that leaders are saying is ‘this problem is so huge we’ve got to work together to deal with it’,” he added.