Immunization is crucial for saving children's lives, but many kids in Tanzania miss out on vaccines. A study in Ilala District used a human-centered design approach to find ways to increase vaccination rates. They discovered reasons for low vaccination, like lack of community leader support and hesitancy among parents. After brainstorming ideas, they focused on using local leaders to promote vaccines. By working closely with government and community leaders, they reached more houses and families than expected, boosting vaccination rates.