This study investigated how positive (e.g., incentives) and negative (e.g., restrictions) reinforcement used in vaccination promotional messages and trust in government impact parental vaccine perceptions and decisions on vaccinating their children during a large-scale infectious disease crisis. Two hundred and eighty-six parents of unvaccinated teens participated in a 2 (reinforcement: positive vs. negative) × 2 (trust in government: high vs. low) between-subjects experimental survey. Positive reinforcement (e.g., gift cards for the vaccinated) was more effective for parents with low trust in the government to improve their attitudes and intentions toward child vaccination, while parents with high trust in the government were unaffected by reinforcement types. To the best of our knowledge, this study is among the first to examine the effects of both positive and negative reinforcement on vaccination perceptions and behavioral intentions through a controlled experiment and is the first study to do so in a large-scale infectious disease crisis setting. This research is expected to help public health professionals better prepare for and manage virus-induced public health crises in the future.