Fans of the television series The Great British Bake Off have long marveled at the skill contestants show during the dreaded "technical challenge" — for which they are given a basket with all the ingredients needed to make a highly unusual dish but a set of instructions that are often as vague as, "Bake until ready." Now a team of scientists at a pharmaceutical startup in South Africa is essentially confronting the same type of test — except the stakes are life and death. The World Health Organization has hired the company, called Afrigen Biologics and Vaccines, as part of...