The covid-19 pandemic has starkly revealed how we need more international cooperation to address global health crises, not less. Not only are we far from addressing all the risks that this insidious virus presents, but the vast majority of people remain susceptible to infection. Consider the vital role that international cooperation is already playing around the development of a covid-19 vaccine. This began almost as soon as the coronavirus’s sequence was shared online, and there are now 141 vaccines in development. Leading candidates may be only months from success. Of course, there is no guarantee of full protection, but we are hopeful.