The UN health agency cited a new study by its regional office in Brazzaville which found that between 83,000 and 190,000 could die and 29 to 44 million be infected during the period.
The research is based on prediction modelling and covers 47 countries with a total population of one billion, the WHO said in a statement.
Experts have consistently warned that Africa is particularly vulnerable to an outbreak, due to weak health infrastructure, high rates of poverty, numerous roiling conflicts and a proven susceptibility to previous epidemics.
But the virus has been slow to spread across the continent, which has yet not recorded the soaring number of infections or deaths seen in Europe, the United States and elsewhere.
“The model predicts the observed slower rate of transmission, lower age of people with severe disease and lower mortality rates compared to what is seen in the most affected countries in the rest of the world,” the statement said.
“The lower rate of transmission, however, suggests a more prolonged outbreak over a few years.”
WHO Africa Director Matshidiso Moeti said that “while COVID-19 likely won’t spread as exponentially in Africa as it has elsewhere in the world, it likely will smoulder in transmission hotspots”.
“COVID-19 could become a fixture in our lives for the next several years unless a proactive approach is taken by many governments in the region,” he added. “We need to test, trace, isolate and treat.”
Smaller countries as well as Algeria, South Africa and Cameroon were at particularly high risk unless effective containment measures were in force, the WHO said.
Africa has so far recorded 53,334 cases and 2,065 fatalities – out of a global death toll of nearly 267,000 -according to an AFP tally.
Several countries have put confinement measures or lockdowns in place, but others have not and some are considering lifting restrictions.
Nigeria lifted the lockdown in Africa’s most populous city Lagos earlier this week, while South Africa started to ease its measures last week.
