The influence of social determinants and health communication on Public health emergency preparedness (PHEP) as well as the mediating effect of health communication were investigated with respect to the 2015 Middle East Respiratory Syndrome (MERS) outbreak in South Korea. Data were collected through a survey six months after the de facto end of the outbreak and a total of 855 subjects completed the surveys and were included in the analysis. The results suggested that the public's preventive (hand hygiene) and avoidance (avoiding hospitals even when sick) behaviors that were frequently practiced during the pandemic were influenced by their social determinants both direct and indirect pathways. Health communication such as information seeking and processing mediated the effect of social determinants on the behaviors and information seeking was found to have the most significant mediating effect on the relationship between the practice of both preventive and avoidance behaviors and social determinants such as education and age. The results of the present study will deepen our understanding of PHEP by identifying key factors that influence the public's behavioral responses as well as providing information to public health emergency management and health risk communication officials to implement strategies necessary in improving PHEP.