For the first time in recorded history viruses, bacteria and other infectious diseases are not the leading cause of death or disability in any region of the world. People are living longer, and fewer mothers are giving birth to many children in the hope that some might survive. And yet, the news is not all good. Recent reductions in infectious disease have not been accompanied by the same improvements in income, job opportunities and governance that occurred with these changes in wealthier countries decades ago. There have also been unintended consequences. Whether the peril or promise of that progress prevails, Bollyky explains, depends on what we do next. Bollyky is the Director of the Global Health Program at the Council on Foreign Relations. Chaired by Isaac Florence.