Despite many African countries struggling to obtain enough Covid-19 vaccines, some have thousands of expired doses which they have been unable to use.
Some countries are now destroying these vaccines, in line with the latest World Health Organization (WHO) advice.
Which countries have unused vaccines?
Malawi has destroyed almost 20,000 doses of the AstraZeneca vaccine, while South Sudan has 59,000 doses which it also plans to discard.
The vaccines had been donated through the African Union but had not been administered by their expiry date of 13 April.
The WHO had originally asked for the vaccines to be kept while it investigated whether the expiry date could be safely extended.
But it now says vaccines already sent out by the manufacturer and which are expired should be thrown away.
“While discarding vaccines is deeply regrettable in the context of any immunisation programme, WHO recommends that these expired doses should be…safely disposed [of],” the WHO says in a statement.
The Democratic Republic of Congo, meanwhile, says it cannot use most of the 1.7 million AstraZeneca doses it received under the global Covax scheme for poorer countries.
Only about 1,000 of the doses had been administered by the end of April.
Most of this batch – with an expiry date of 24 June – is now being sent to other countries, with some already delivered to Ghana and Madagascar.
Why have vaccines not been used?
The AstraZeneca vaccine can be stored safely in refrigerated conditions for up to six months after production.
And the African Union redistributed batches originally delivered to South Africa in February, which had a 13 April expiry date.
The South African government decided not to use them, concerned the vaccine offered insufficient protection from the variant prevalent in the country.
And, in late March, the one million doses it had were sold on to the African Union to give to other African countries.
But some, such as South Sudan, say they were not made aware of the expiry date.
Nigeria, meanwhile, said it would be unable to use all the doses in time. So some were reassigned to neighbouring Togo and Ghana.
And some were even sent to Jamaica.
The WHO says only Togo and The Gambia have confirmed they used all these doses by the expiry date.
And information about what has happened to the rest is currently unavailable.
What caused delays in using vaccines?
Many countries failed to prepare adequately before receiving the vaccines, Phionah Atuhebwe, from the WHO in Africa, says.
“That is one of the reasons we are seeing the slow pace of rollout,” she says.
And some countries also faced financial challenges.
Africa Centres for Disease Control head John Nkengasong says countries need more support to increase the numbers of health workers and obtain supplies, such as personal protective equipment.
And those who have vaccines approaching or beyond their expiry date should contact the WHO or Africa CDC.
“The continent as a whole knows how to vaccinate and has been vaccinating for other diseases,” he says.
“But the key is how do you scale that up – and… at speed?”
For DR Congo, the former Zaire, the problem is not only weak health services but also a very poor transport network – making the delivery of vaccines to remote areas a major issue.
To complicate matters further, the country suspended its Oxford-AstraZeneca vaccine rollout in mid-March, amid safety concerns, and resumed it on only 19 April – more than a month later.
What about vaccine hesitancy?
Some experts and politicians blame concerns over the safety and efficacy of vaccines in general for the slow uptake in many countries in Africa – but it is hard to quantify that impact.
“It took a while to convince people,” Sierra Leone Health Minister Austin Demby tells BBC News
“So it is not just vaccine hesitancy, it is like [having] vaccine sceptics to start with.”
Malawi virologist Gama Bandawe says mistrust of vaccines has played a role in the country being unable to use all the supplies it has received.
And South Africa’s decision to stop using the Oxford-AstraZeneca vaccine, amid concerns around cases of blood clots, may have added to these doubts.
“The government did the best they could – but perhaps the general public has not been as receptive as was expected,” he says.
A study commissioned by Africa CDC on Covid-19 vaccine perceptions in 15 countries indicated a significant proportion of people had concerns around vaccine safety.
On average, about 20% of respondents said they would not have a vaccine – but the proportion varied from below 10% in Ethiopia, Niger and Tunisia to 41% in DR Congo.