As we are seeing with the coronavirus today, disease can profoundly impact a community—upending routines and rattling nerves as it spreads from person to person. But the effects of epidemics extend beyond the moments in which they occur. Disease can permanently alter society, and often for the best by creating better practices and habits. Crisis sparks action and response. Many infrastructure improvements and healthy behaviors we consider normal today are the result of past health campaigns that responded to devastating outbreaks.