STI Shield: Empowering African Young Adults with STI Awareness Through a Multi-Chatbot Mobile Solution

Abstract

Sexually transmitted infections (STIs) remain a major health concern in sub-Saharan Africa, where young adults face heightened vulnerability due to limited sexual health knowledge, risky behaviors, stigma, and restricted healthcare access. This thesis presents STI Shield, a culturally tailored multi-chatbot mobile app designed to enhance STI awareness and promote safer sexual behaviors among African young adults. Guided by the Health Belief Model and Persuasive System Design principles, STI Shield combines rule-based and large language model (LLM) chatbots, leveraging the structured delivery of rule-based systems and the flexibility of LLMs. A two-phase evaluation, including a pilot and in-the-wild study, showed high usability, strong educational impact, and positive changes in key behavior determinants. Participants rated the app highly for trustworthiness, inclusivity, cultural appropriateness, and emotional impact. This work contributes to advancing knowledge on healthcare chatbots and provides insights into designing mobile health apps for sexual health education and behavior change.