Africa recorded a 43% jump in COVID-19 deaths last week as infections and hospital admissions have risen and countries face shortages of oxygen and intensive-care beds, the World Health Organization said on Thursday.

The continent's case fatality rate - the proportion of deaths among confirmed cases - stands at 2.6% against the global average of 2.2%, WHO Africa said in its weekly briefing.

"Africa's third wave continues its destructive pathway, pushing past yet another grim milestone as the continent's case count tops six million," Matshidiso Moeti, WHO Regional Director for Africa, told the briefing.

The surge in infections, which is partly driven by the presence of the highly transmissible Delta variant of the coronavirus in 21 African countries, is leaving a "brutal cost in lives lost" in its trail, she said.

Deaths have climbed steeply for the past five weeks to 6,273 last week, just a percentage point shy of its weekly peak recorded in January.

"This is a clear warning sign that hospitals in the most impacted countries are reaching a breaking point," Moeti said.

Namibia, South Africa, Tunisia, Uganda and Zambia accounted for the bulk of the fatalities, WHO said.

Public fatigue with restrictions to daily life aimed at curbing the spread of the virus was also to blame for the surge, WHO Africa said, which has seen the continent record an increase of 1 million cases in the shortest time so far in the pandemic.

It took just a month for infections to increase by the latest 1 million, compared with the three months it took to rise to 5 million from 4 million, Moeti said.

Monoclonal antibody therapies, which the WHO approved for treatment of COVID-19 patients last week, will be out of reach for many people in Africa due to their high price tag of about $2,000 per patient, she said.

"We are advocating for generics to be produced rapidly to make these products more affordable," she said.

Africa was forced to pause its vaccine roll-out due to supply challenges and only 53 million doses of COVID-19 vaccines have been administered so far, Moeti said, and only 18 million Africans are fully vaccinated. The continent's population is 1.3 billion.

"This clearly needs to urgently increase," she said, adding that deliveries from the United States, Europe and the global vaccine sharing COVAX scheme are expected to gather pace in the next few weeks.

(This story has been refiled to fix day of the week in first paragraph)

Reporting by Bate Felix in Dakar and Duncan Miriri in Nairobi; editing by Mark Heinrich