G7 and EU nations can afford to donate more than 150 million vaccines to countries in need without compromising their own objectives, UNICEF said Monday.
The Group of Seven industrialised powers and the European Union could help close the world's vaccine gap by sharing just 20 percent of their June, July and August stocks with the Covax jab scheme for poorer nations, a study by British firm Airfinity showed.
"And they could do this while still fulfilling their vaccination commitments to their own populations," UNICEF director Henrietta Fore said.
UNICEF, the United Nations Children's Emergency Fund, is flying Covax doses to poorer countries due to its expertise in vaccine logistics.
Britain is due to host its fellow G7 members Canada, France, Germany, Italy, Japan and the United States for a summit in June.
By that time, UNICEF said the Covax programme -- co-led by Gavi the Vaccine Alliance, along with the World Health Organization and the Coalition for Epidemic Preparedness Innovations -- will find itself 190 million doses short of what it had planned to distribute.
- 'Share them now' -
The programme's aim of ensuring the vaccination of 20 percent of populations in all countries by the end of this year "is at risk", Bruce Aylward, the WHO lead on Covax, acknowledged Monday.
It was possible to make up for the delays if countries in a position to do so could donate doses, he told reporters.
"We determine our future right now," he added.
WHO chief Tedros Adhanom Ghebreyesus agreed.
"We need high-income countries that have contracted much of the immediate global supply of vaccines to share them now," he told reporters.
He insisted that "Covax works", pointing out that the programme had delivered some 65 million doses to 124 countries so far.
"But it is dependent on countries and manufacturers honouring their commitments."
The current shortfall is in part due to a devastating flare-up of the virus in India. While the country had been due to manufacture and export the majority of Covax doses, it is now putting them to use at home instead.
With additional shortages in supplies and funding, the UNICEF statement called for swift action until more sustainable production models were within reach.
"Sharing immediately available excess doses is a minimum, essential and emergency stop-gap measure, and it is needed right now," it read.
The United States has 60 million AstraZeneca doses it could share, while France has pledged 500,000 doses and Sweden one million, with Switzerland considering a similar donation.
- Yawning gap -
Some 43 percent of the 1.4 billion doses of COVID-19 vaccines so far injected around the world have been administered in high-income countries accounting for 16 percent of the global population.
Just 0.3 percent have been administered in the 29 lowest-income countries, home to nine percent of the world's population.
That yawning gap spurred Tedros to ask vaccine-wealthy nations last Friday to refrain from giving jabs to children and adolescents and instead donate those doses to Covax.
The urgency stems from more than mere fairness: wherever the virus continues to circulate it could give rise to more contagious or more deadly variants that could threaten progress toward immunity.
"We are concerned that the deadly spike in India is a precursor to what will happen if those warnings remain unheeded," said UNICEF.
"Cases are exploding and health systems are struggling," it said, in countries like Nepal, Sri Lanka, Maldives, Argentina and Brazil.