The coronavirus has overwhelmed health-care systems in a number of highly developed nations. Now, it is spreading to some of the world’s most vulnerable countries, with health officials in Africa and Latin America fearing the impact will be devastating. At least 26 of Africa’s 54 countries have confirmed cases. The prospect of a mass outbreak is particularly alarming for a region with a shortage of some 1.8 million health workers that is already suffering the world’s largest disease burden, according to…