Millions of vaccinations have already been administered globally but vaccine distribution is far from equal.
For two months, the US-based Duke University Global Health Innovation Centre (GHIC) has been tracking and publishing the purchase of vaccines relative to where the disease burden is and the income level of the countries.
Its research shows of the more than seven billion doses bought world wide, more than four billion have been snapped up by high-income countries, whereas low income nations have secured just 270 million.
The global initiative - known as COVAX - which will distribute free vaccines to poorer countries to cover 20 per cent of their population - has purchased just over one billion.
