Some countries such as South Africa, Zimbabwe and Ghana have received vaccines, but many others will have to wait until later in the year for stocks to arrive.

There has been global competition to get hold of vaccines, and African countries have generally not been as successful as richer countries in securing supplies.

"It is deeply unjust that the most vulnerable Africans are forced to wait for vaccines while lower-risk groups in rich countries are made safe," says Matshidiso Moeti, the World Health Organization (WHO) regional director for Africa.

France President Emmanuel Macron has proposed that rich countries in Europe and the US share their vaccines with Africa.

He says he wants some doses made available quickly for African countries.

The ones which have so far got vaccines have largely done so through direct purchases from manufacturers, or as donations from countries such as China, Russia, India and the United Arab Emirates (UAE).

African countries have been hoping to get vaccines through international and regional schemes.

The principal one is the global Covax initiative, in which countries pool their resources to support the development of effective vaccines with a view to ensuring that everyone gets a fair supply.

The first vaccines distributed under the Covax programme have now arrived in Ghana.

The WHO says it will initially deliver 90 million vaccine doses to African countries, enough to cover 3% of the continent's population.