Hesitancy to take safe vaccines is a long-standing problem that predates Covid-19 and the outbreaks of measles surging in recent years. Some of the most effective interventions for vaccine hesitancy involve counseling sessions with trusted physicians who can address individual concerns. Unfortunately, such approaches are time consuming, costly, and depend on citizens having ready access to trusted primary care physicians. To overcome these barriers, this research team will iteratively develop and test an online, individually-tailored, and interactive video-based decision aid, designed to help people make decisions about vaccines by helping them become informed by a better understanding of their risks and benefits, how vaccines work, and how vaccines are developed. Using a data efficient, incremental approach to randomized trials, the team will follow-up with participants to test whether engaging with these decision aids increases their uptake of both Covid-19 and influenza vaccines. If impactful, the team will make the final interactive decision aid freely available in both English and Spanish.