The Covid-19 vaccine allocation plan – co-led by the World Health Organization and known as Covax – has been set up to ensure that the research, purchase and distribution of any new vaccine is shared equally between the world’s richest countries and those in the developing world.

Sixty-four higher income economies have already joined Covax, which includes commitments from 35 economies as well as the European commission, which will procure doses on behalf of the 27 EU member states plus Norway and Iceland, with 38 more expected to join in the coming days.

Ultimately the scheme aims to deliver 2bn doses of safe, effective vaccines around the world by the end of 2021.

Governments, vaccine manufacturers, organisations and individuals have committed $1.4bn (£1.1bn) towards vaccine research and development so far.

Recognising that the first useful vaccines to emerge may be in short supply, approved vaccines will initially be made available to a tightly targeted 3% of the population of participating countries, building over time to 20% of each country’s most vulnerable population.

Unveiling the agreement at a briefing in Geneva on Monday, Tedros Adhanom Ghebreyesus, head of the UN health body, said Covax represented the “world’s largest and most diverse portfolio of Covid vaccines” in which the priority would be given to those most at risk.

“This is a mechanism that enables global coordination of the rollout for the greatest possible impact and will help bring the pandemic under control and ensure the race for vaccines is a collaboration not a contest,” he said.

He added that the scheme would ensure vaccines for “some people in all countries and not all people in some countries”.

According to a document detailing the arrangement, under the scheme “all countries should gradually receive tranches [of vaccine] to cover each subset of their [initial] target groups … until they can cover 3% of the population”.

The document continues: “At this point of the pandemic, a reasonable scenario would be that, while the supply of Covid-19 vaccines remains very scarce, countries should focus initially on reducing mortality and protecting the health system.

“This … would enable, for example, the vaccination of frontline workers in health and social care settings in most countries … Additional tranches will follow gradually as more supply becomes available.”

While decisions on the distribution of vaccines initially supplied under the scheme will remain at individual nations’ discretion, it said it was encouraging “countries to consider these recommendations and to be transparent about their decision-making processes and ultimate use of the vaccine”.

Set up to counter the increasing threat of so-called “vaccine nationalism” in the midst of the ongoing pandemic, Covax is being led by the WHO, Gavi, the Vaccine Alliance, and the Coalition for Epidemic Preparedness and Innovations (Cepi) to ensure the “equitable access and allocation of Covid-19 health products”, not least vaccines.