Adolescent girls and young women (AGYW) between the ages of 15-29 years continue to bear the brunt of Human Immunodeficiency Virus (HIV) infections in South Africa despite progress recorded in prevention and treatment programmes. The ongoing susceptibility of young women to HIV infection and the sub-optimal uptake of prevention options such as Pre-Exposure Prophylaxis (PrEP) that are highly effective creates a need for an HIV vaccine to benefit populations at substantial risk of HIV infection. However, lessons from previous vaccine studies and the recent COVID-19 vaccine have highlighted significant barriers to vaccine uptake, such as widespread misinformation and vaccine hesitancy. These challenges threaten the successful implementation of a future HIV vaccine. Building on these insights, this study will utilise psychological inoculation theory to develop and evaluate HIV vaccine messages among adolescent girls and young women. Primary objective: To compare changes in intentions to receive HIV vaccine following misinformation exposure in groups with and without psychological inoculation and behavioural economics boost. Secondary objectives: (1) To compare believability and persuasiveness of misinformation claims and motivational threat associated with misinformation in groups with and without psychological inoculation and behavioural economics boost. (2) To explore subgroup effects by relevant sociodemographic and behavioural factors including HIV risk, PrEP history, COVID-19 vaccine history, general vaccine hesitancy, and information avoidance. The investigators will conduct a two-arm randomized controlled trial of 2-3 inoculation messages that address emerging myths and misinformation about the HIV vaccine in South Africa. Participants will be randomly assigned to a control group or an intervention arm: enhanced inoculation message with insights from behavioural economics.