Many of the people who are exposed never become deathly ill and some may not even notice symptoms. That is one of the insidious things about this bug.
The reponse of a given individual to an infection is dictated by genetics. either you have the genes that direct an effective immunological response or you don’t. throughout history a disease goes through a given population numerous times killing off the “susceptible” people who cannot mount an effective immunological response. Eventually the surviving population is “immune” since they have the necessary genes to mount an effective immunological response. Consider bubonic plague it ravaged Europe repeatedly until the late 17th century. Yet despite the horrendous conditions in urban areas, concentration camps and prisoner of war camps there were no outbreaks during WW II and its immediate aftermath. Why? The Europeans who’s ancestors had survived the bubonic plague as a population had the gene to protect them. Eventually and painfully the same thing will happen in Africa.Of course it would be beneficial to have an effective treatment or vaccine to mitigate the suffering.