The Gates Foundation and British biomedical charity Wellcome on Tuesday pledged $150 million each in the fight against Covid-19 and to prepare for future pandemics.
The $300 million will go to the Coalition for Epidemic Preparedness Innovations (CEPI), a global partnership founded five years ago that co-leads Covax, the initiative to distribute Covid vaccines across the developing world, alongside the World Health Organization and Gavi, the Vaccine Alliance.
"We need a truly global response," he added, urging governments to step up their contributions.
The announced investment makes up only a small fraction of CEPI's new five-year action plan, which calls for $3.5 billion.
A conference organized next March in London should help to raise the target sum.
Founded in 2017 following the Ebola epidemic, CEPI has made major contributions to the fight against the coronavirus pandemic.
It has provided funding for 14 vaccine projects, including those of AstraZeneca, Moderna and Novavax.
But the picture is mixed, he added, and "we didn't get the quantity to the developing countries as quickly as we wanted."
One of CEPI's key goals is to drastically reduce the time it takes to develop life saving vaccines against any new viral threat to within 100 days of the pathogen being sequenced.
"Delivering vaccines in 11 months as we did in 2020 was unprecedented. But it was certainly not good enough," said CEPI CEO Richard Hatchett.
"The unprecedented spread of the highly infectious Omicron variant around the world over the past two months exemplifies the ways in which we must be ready, both in terms of speed and the scale of our response, to respond to future threats," he added.