This includes 64 higher-income economies, which are self-financing in procuring the Covid-19 vaccines once available, and 92 low- and middle-income economies eligible for support for the procurement of vaccines through the COVAX Advance Market Commitment (AMC) coordinated by the Gavi, the Vaccine Alliance, a financing instrument aimed at supporting the procurement of vaccines for these countries, Xinhua news agency reported.

"This means that 156 economies, representing roughly 64 per cent of the global population in total, are now either committed to or eligible for the COVAX Facility, with more to follow," the WHO said in a statement on Monday.

The COVAX Facility is part of COVAX, the vaccines pillar of the Access to Covid-19 Tools (ACT) Accelerator, which is co-led by the Coalition for Epidemic Preparedness Innovations (CEPI), Gavi and the WHO, in partnership with developed and developing country vaccine manufacturers, Unicef, the World Bank, civil society organizations and others.

The allocation of Covid-19 vaccines aims at ensuring that no participating economy will be left behind, as policies determining the prioritization of vaccine rollout within economies will be guided by recommendations from the WHO Strategic Advisory Group of Experts on Immunization.

The WHO said that those fully self-financing economies will now unlock vital funding and the security of demand needed to scale up manufacturing and secure the doses needed for the COVAX Facility.

Currently, CEPI is leading COVAX vaccine research and development work, which aims to develop at least three safe and effective vaccines.

Nine candidate vaccines are being supported by CEPI, eight of which are in clinical trials.

COVAX's core aim is to have 2 billion vaccine doses available by the end of 2021.

According to the WHO, governments, vaccine manufacturers, organizations and individuals have committed $1.4 billion towards vaccine R&D so far, but the initial target in seed funding needed by the end of 2020 amounts to $2 billion.

The commitment agreements secured also commit higher income governments to provide an upfront payment to reserve doses by October 9.

These funds will be used to accelerate the scale-up of vaccine manufacturing to secure 2 billion doses of vaccine, enough to vaccinate 1 billion people assuming the vaccine requires a two-dose regimen.

The WHO said that the COVAX Facility will now start signing formal agreements with vaccine manufacturers and developers to secure the doses needed to end the acute phase of the pandemic by the end of 2021.