Rumors and fears of epidemics generally circulate in the aftermath of disasters, and earthquakes are no exception. Outbreaks of infectious disease generally have not followed earthquakes in other countries and are unlikely to occur in the United States. Health officials, however, should be prepared to recommend appropriate sanitary precautions and to dispel unfounded rumors and inaccurate information. They should set up a disease surveillance mechanism appropriate to the circumstances and provide regular reports to disaster-response officials. Any unusually high incidence of disease should be investigated and control measures implemented. Mass vaccination campaigns not based on results of public health surveillance are inappropriate following earthquakes.