The African Union's disease control body on Thursday urged countries to use COVID-19 vaccines donated to them quickly to save lives and livelihoods, after confusion in Malawi and South Sudan about whether doses they received had expired.

"My appeal to member states is: if we are doing our part to mobilise these vaccines, you do your part and use the vaccines," John Nkengasong, director of the Africa Centres for Disease Control and Prevention (Africa CDC), told a news conference.

Malawi plans to destroy more than 16,000 doses of AstraZeneca's vaccine manufactured by the Serum Institute of India because the shots were not administered before the April 13 expiry date on the packaging. The doses were supplied via the AU thanks to a donation from telecoms group MTN

South Sudan has set aside 59,000 doses supplied by the AU and does not plan to use them because of the same expiry issue, a government official told Reuters last week.

But Nkengasong, the continent's top public health official, said the Africa CDC had informed countries receiving the donations that the shots could be used until mid-July, based on a further analysis conducted by the Serum Institute.

"The Serum Institute expanded that deadline based on their own analysis to July 13, and we shared that information with the countries," he said. "We are in an emergency situation, and it is my appeal to all member states that when you get your vaccines, put down the right systems to use those vaccines quickly."

African countries have struggled to secure enough COVID-19 vaccines to roll out mass immunisation campaigns.

Many are reliant on donations from global vaccine distribution scheme COVAX, which is co-led by the World Health Organization and partners including the Gavi vaccines alliance.

Nkengasong said that so far 15 million COVID-19 vaccine doses had been administered in Africa, out of a population of 1.3 billion. The Africa CDC has set a target of vaccinating 60% of the continent's population, or 750 million people.