This case study uses a story involving time travel to help students integrate basic concepts in immunology, sociology, psychology, bioethics, and cultural competency, which are essential for improving public health related to vaccine-preventable infections and health literacy. Even before the COVID-19 pandemic began, vaccine hesitancy was identified by the World Health Organization (WHO) as one of the top ten threats to global health; it is even more of a priority now in that pandemic’s wake. This case provides students with a platform to discuss a variety of topics including cognitive biases, herd immunity, trusted messengers, and the dangers of mis/disinformation in various forms of media. Global examples are presented across multiple continents and include vaccine-preventable illnesses such as polio, measles, mpox, and COVID-19. This case study is designed for an upper-level university biology or public health course in which students already have some basic background knowledge regarding viruses, vaccines, and infectious disease.