Neisseria gonorrhoeae (Ngo), the causative agent of the sexually transmitted infection (STI) gonorrhea, is a major public health problem worldwide. The clinical outcomes of gonococcal infection range from asymptomatic infection to severe sequelae that include pelvic inflammatory disease, adverse pregnancy outcomes, neonatal complications and infertility. Infection with Ngo also increases the risk of acquiring and transmitting HIV. The increasing incidence of gonococcal infection and the emergence of multidrug resistant ‘superbug’ strains of Ngo make it clear that a vaccine-based intervention is urgently needed. In this project our overall goal is to gather the data required to understand any potential barriers to the widespread implementation of a gonococcal vaccine, to determine what information might increase uptake, and to identify the vaccine features and vaccination strategy that will have the maximum impact on reducing the prevalence of gonorrhea. These studies are highly significant given that the ability to rapidly evaluate and implement a gonococcal vaccine, once available, is essential. The specific aims are: AIM 1: Describe the distribution and transmission of Ngo with different phenotypes, and determine variability among vaccine targets. AIM 2: Among various populations, describe understanding of gonococcal disease and perceptions of risk as well as assess acceptance of a gonococcal vaccine. AIM 3: Model the potential impact of different vaccine formulations and different target populations to guide gonococcal vaccine development and implementation.