This study proposes a theory-driven model to concurrently examine the cognitive and emotional factors that motivate vaccine supporters to combat erroneous online anti-vaccination information. The model was tested using data from a web survey of 599 vaccination supporters in the United States. The vaccine supporters reported greater support for government regulation of misinformation when they perceived greater susceptibility among the general public to the influence of misinformation. Surprisingly, the perceived severity of the influence was inversely related to respondents' intention to correct misinformation. In addition, perceived susceptibility to the influence of anti-vaccine misinformation and perceived severity of its influence on others induced negative emotions that included anticipated guilt and anger. The negative emotions in turn motivate vaccine supporters to attitudinally support government's media restriction or behaviorally correct the online misinformation.