The present study focused on the success story of Vietnam’s ability to control the COVID-19 outbreak in the early stages to examine the associations between exposure to the Vietnam Ministry of Health’s COVID-19 prevention social media campaign messages, interpersonal communication, attitudes, perceived norms, self-efficacy, and intentions to stay at home. A cross-sectional survey was conducted with residents in Ho Chi Minh City (N = 360). Results from mediation analyses indicated that interpersonal communication mediated the effect of social media campaign exposure on intentions to stay at home. Moreover, interpersonal communication shaped injunctive norms and self-efficacy that were conducive to behavioral intentions. These results underscored the need to leverage the power of social media and interpersonal communication in public health campaigns to prevent infectious outbreaks.