World leaders have pledged $8.8 billion for Gavi, the Vaccine Alliance, far exceeding the target of $7.4 billion.
The funding will help immunise 300 million more children in the world's poorest countries against diseases like measles, polio and diphtheria by the end of 2025.
It will also support health systems to withstand the impact of the novel coronavirus and maintain the infrastructure necessary to roll out a future Covid-19 vaccine on a global scale.
The pledges were made at the Global Vaccine Summit 2020, hosted by UK Prime Minister Boris Johnson on Thursday.
Representatives from 52 countries, including 35 heads of state, joined leaders from global health organisations, the private sector, vaccine manufacturers and civil society organisations to support the Vaccine Alliance's work protecting almost half the world's children against deadly, preventable diseases.
The UK remains the Vaccine Alliance's largest donor, pledging the equivalent of £330 million per year over the next five years.
Other top donors include the Bill and Melinda Gates Foundation, Norway, Germany and the United States.
Eight countries, including Bhutan, Burkina Faso, Cameroon, Finland, Greece, New Zealand, Portugal and Uganda, made their first ever pledge to Gavi.
As well as supporting the routine vaccination of hundreds of millions of children in lower-income countries from infectious diseases, the new support will also be used to help lower-income countries meet the challenge of the coronavirus pandemic by strengthening health systems and vaccine distribution.
At the programme, UK Prime Minister Boris Johnson said, "You can count on our full contribution as together we rise to fulfil the greatest shared endeavour of our lifetime - the triumph of humanity over disease, now and for the generations that follow."
"As we make the choice today to unite and forge a path of global co-operation, let us also renew our collective resolve to find the vaccine that can defeat coronavirus," he added.
Bill Gates, co-chair of the Bill and Melinda Gates Foundation, said, "To beat the Covid-19 pandemic, the world needs more than breakthrough science. It needs breakthrough generosity. And that's what we're seeing today as leaders across the public and private sectors are stepping up to support Gavi – especially Prime Minister Johnson."
He further said, "When Covid-19 vaccines are ready, this funding and global coordination will ensure that people all over the world will be able to access them."
Over the next five years, we will also see the largest investment in immunisation ever made by lower-income countries, said a press release issued by Gavi.
Gavi, the World Health Organisation and Unicef have warned that 80 million children under the age of one are at risk of disease due to disruptions to vital immunisation programmes because of coronavirus.
Gavi-supported countries will contribute $3.6 billion towards the cost of buying vaccines – more than double the amount for the 2016-2020 period and more than 40 percent of the total estimated cost of supplying vaccines to these countries.
They are also expected to invest around $6 billion in immunisation service delivery costs over the same period. The dire economic effects of the Covid-19 pandemic may, however, disrupt these estimates.
Gavi's market-shaping efforts to make life-saving vaccines more affordable have seen a 21 percent price reduction for fully immunising a child with pentavalent, pneumococcal and rotavirus vaccines – from $20 in 2015 to $15.90 in 2018.
Included in the total figure is $0.9 billion in long-term pledges made to the innovative International Finance Facility for Immunisation (IFFIm), which will be used when needed to raise immediate funds on the capital markets.
World's biggest vaccine manufacturers also committed to continue supplying the billions of doses needed to continue increasing vaccine coverage across Africa and Asia.
The Global Vaccine Summit also saw the launch of the Advance Market Commitment for Covid-19 Vaccines (COVAX AMC), a new innovative financing instrument to provide access to Covid-19 vaccines for low and middle-income countries.
This is the first building block towards a global mechanism to ensure equitable access to future Covid-19 vaccines.
Some $567 million was raised in initial seed money for the AMC from 12 donors.
Gavi Board Chair Dr Ngozi Okonjo-Iweala said, "We have made incredible progress over the past two decades improving vaccine coverage and reducing child mortality across Africa and Asia."
He expressed his hope that this funding will give countries new hope that, despite the devastating impact of Covid-19, this progress can be sustained and built on.
Dr Seth Berkley, CEO of Gavi, said, "One thing that has been made all too clear over the past few months is that this disease does not respect borders, which is why this global problem requires a global solution."
The Vaccine Alliance is one of the world's largest and most successful public-private partnerships, and the wider private sector continued to show support for its mission with the announcement of more than $70 million of new pledges and partnerships, bringing new technology, networks and expertise to help solve some of global health's most intractable problems.