Tedros Adhanom Ghebreyesus, director general of World Health Organization, said it was not fair for younger, healthy people in richer nations to get injections before vulnerable people in poorer states.

According to Ghebreyesus, more than 39 million vaccine doses had been given in 49 richer states - but one poor nation had only 25 doses.

Oxfam has also estimated that low and middle-income countries may have less than 10% of their populations vaccinated by the end of 2021.