Pedestrians wearing face masks walk on the seaside in Cape Town, South Africa, Dec. 5, 2021.(Photo: Xinhua)

Twenty mostly African countries have still not vaccinated even 10 percent of their population against COVID-19, the World Health Organization's vaccine advisers lamented Monday.

The Strategic Advisory Group of Experts on Immunisation (SAGE) said the speed of the COVID-19 jab rollout had been "unprecedented."

However, 20 countries - down from 34 in January - had still not managed a 10-percent immunization rate, Kate O'Brien, the WHO's vaccines chief, told reporters.

"These are countries that are working really hard to advance their programs. Supply is no longer the issue. The legacy of all the supply constraint from 2021 - the effects of that [are] still being felt," she said.

SAGE said vaccination coverage among the groups most vulnerable to severe COVID-19 disease was not enough to give them the protection they needed.

Health worker coverage is at 65 percent overall.

"That's certainly a very, very strong position to be in, but we're really carrying the message forward that it needs to be 100 percent," said O'Brien.

Coverage in the over-60s is at 69 percent.

So far, the WHO has authorized eight COVID-19 vaccines and versions thereof, giving them the green light with its emergency use listing (EUL) status.

SAGE said that available data on their effectiveness against the Omicron variant of COVID-19 generally showed waning immunity against infection but high and more sustained effectiveness against severe disease and death. However, it added: "Data remains very limited for some of the WHO EUL vaccines" in their performance against Omicron.

AFP