As the more contagious Delta variant starts to spread across the least-vaccinated continent, cases are rising, hospitals are being overrun and deaths are mounting. With little prospect of a significant proportion of Africans being vaccinated in coming months as rich nations continue to hoard shots, epidemiologists expect another wave of disease will follow before the end of the year. That carries the risk of more vaccine-resistant variants developing, endangering not just Africans, but also the rest of the world. "This third wave is going to be devastating because in Africa and South Africa, we couldn't get access to vaccines when we needed them most," said Professor Tulio de Oliveira, the director of Krisp, a South African genetic-sequencing institute.