A new World Bank financing mechanism will allow developing countries to purchase Covid-19 vaccines collectively through the Covax facility, the scheme announced Monday.
Covax was set up to ensure 92 developing territories could access coronavirus vaccines to fight the pandemic, with the cost covered by donors.
The new mechanism will allow those countries to buy additional doses on top of the subsidised ones they will already receive via Covax.
Using money from the World Bank and other development banks, the facility says it will make advanced purchases from vaccine manufacturers based on aggregated demand across countries.
Under the World Bank financing arrangement, up to 430 million additional doses, or enough doses to fully vaccinate 250 million people, would be available for delivery between late 2021 and mid-2022 for the 92 countries that currently get their vaccine doses covered by donors.
Countries should also have some flexibility in selecting to buy particular vaccines that align with their preferences.
Covax is co-led by the World Health Organization (WHO), the Gavi vaccine alliance and the Coalition for Epidemic Preparedness Innovations.
The financing mechanism "will allow Covax to unlock additional doses for low- and middle-income countries" Gavi chief executive Seth Berkley said in a statement.
"As we move beyond initial targets and work to support countries' efforts to protect increasingly large portions of their populations, World Bank financing will help us advance further towards our goal of bringing Covid-19 under control."
The WHO has raged against the staggering imbalance in global distribution of Covid-19 vaccine doses.
Nearly 3.9 billion doses of Covid-19 vaccines have been injected around the world in at least 216 territories, according to an AFP count.
In high-income countries, as defined by the World Bank, 95.4 doses have been administered per 100 inhabitants.
That figure stands at just 1.5 doses per 100 people in the 29 lowest-income countries.
Covax has so far delivered more than 138 million vaccine doses to 136 participating territories -- far short of the numbers it hoped to have delivered by this point.
"Accessing vaccines remains the single greatest challenge that developing countries face in protecting their people from the health, social, and economic impacts of the Covid-19 pandemic," said World Bank president David Malpass.
"This mechanism will enable new supplies and allow countries to speed up the purchase of vaccines. It will also provide transparency about vaccine availability, prices, and delivery schedules."