The East Africa Centre for Vaccines and Immunization (ECAVI) organizes the Annual vaccinology course for health Professionals that equips them to be agents of change and champions for immunization in their localities. Training health workers is a central Pillar of ECAVI, driven by our own research finding that most caregivers rely on health workers for information and advice regarding treatment and immunization choices and decision making. Understanding the threat posed by vaccine hesitancy, how vaccines work, how they are developed, vaccine preventable diseases and their epidemiology, best practices and legal issues in vaccination are some of the topics addressed in the course. The rising cases of health worker and community vaccine hesitancy, adverse events following immunizations, anti-vaccine sentiments, and resurgence of diseases like measles have all increased need for more advocacy and training on better standardized immunization practices and response.