While confirmed Covid-19 cases and death rates remain low in many African countries, early results in some communities suggest a higher number of infections than those reported, said Dr. Matshidiso Moeti, the WHO Regional Director for Africa.
"Preliminary analysis suggests that over 80% of cases in Africa are asymptomatic," she said during a press briefing Thursday.
The swift action of governments on the continent to impose early lockdowns, and the public's general adherence to movement restrictions, created a "window of opportunity" to keep cases low, Dr. Moeti said. Since many countries have begun easing restrictions and opening economies back up, there has been an uptick of cases.
But experts are unable to conclusively explain the low death rates on the continent. "We don't know the exact factors that are causing it, we just know that some of the factors are more probable," said Dr. Sam Agatre Okuonzi from Uganda.
The panel described probable factors such as a majority youthful population, the frequency with which many Africans spend outdoors and the less movement and interaction in rural areas, as potential explanations.
Another potential factor scientists are studying is the level of potential cross-immunity that has developed from exposure to previous coronaviruses.
"Research is required to characterize the disease and the pandemic in Africa and this work is just beginning," Dr. Okuonzi said.