Dozens of countries have pledged a total of almost $2.4 billion to the Covax vaccine-sharing plan, which is distributing inoculations to the world's poorer nations.
UN Secretary General Antonio Guterres said Wednesday’s drive put Covax "on a war footing to finance the fight".
During a video conference hosted by Japan and the Gavi Vaccine Alliance, which leads the Covax programme alongside the World Health Organisation, almost 40 donor nations, companies and charities promised money and medicine.
Among the donors were Canada, Sweden, Austria, Switzerland, Luxembourg and Mauritius.
“There’s a need to close the funding gap as soon as possible,” said Toshimitsu Motegi, Japan’s Foreign Minister.
The Japanese Prime Minister, Yoshihide Suga, pledged $800 million after an emergency call last week from Covax to help fill a funding shortfall caused by the Covid-19 outbreak in India.
Mr Suga called the drive "an extremely significant and meaningful step" towards equitable vaccine access.
"We have taken a big step towards ‘one world protected'," said Jose Manuel Barroso, the chairman of Gavi.
Mr Barroso said the new funds took total Covax financing to $9.6bn.
"Only by leading by example will we be effective in preaching solidarity," said Spanish Prime Minister Pedro Sanchez, who pledged 15 million doses and €50m ($61m).
Covax wants to distribute 2 billion vaccine doses to the world by the end of the year.
So far, it has distributed 77 million doses to 127 countries and it aims to increase access to cover nearly 30 per cent of the populations of poorer nations.
"Of the 1.8 billion vaccines administered globally, just 0.4 per cent have been administered in low-income countries,” said the WHO's Director General, Dr Tedros Adhanom Ghebreyesus.
"This is ethically, epidemiologically and economically unacceptable."
Dr Tedros repeated long-running concerns that western nations had vaccinated high percentages of their people, while health workers in places such as Africa remained unprotected.