NAIROBI, March 11 (Xinhua) -- The deployment of COVID-19 vaccine in Africa has accelerated as the continent's caseload hit nearly 4 million, a World Health Organization (WHO) official said on Thursday.

Matshidiso Moeti, WHO regional director for Africa said that arrival of additional vaccine doses will boost efforts to contain the pandemic in the continent.

"But doses will remain limited and it is critical that frontline health workers and other priority groups are at the front of the queue," Moeti said in a statement issued in Nairobi.

According to WHO, more than 14.6 million COVID-19 vaccine doses have been delivered to 22 African countries since February 24 under the COVAX facility.

Ten countries in the continent have started inoculating vulnerable groups using COVAX-funded vaccines while another ten began immunizing their citizens with vaccines procured through bilateral arrangement and donations.

Statistics from WHO indicate that more than 518,000 doses of COVAX supplied vaccines have been administered mainly to healthcare workers in Africa.

Moeti said the pandemic has taken a heavy toll on Africa's healthcare workers who account for about 3.5 percent of total caseload in the continent.

Moeti said WHO is assisting African countries to improve their capacity on COVID-19 surveillance, testing, contact tracing and treatment amid the quest to reopen economies fully.