Chlamydia trachomatis is an obligate intracellular bacterium that is responsible for the most common sexually-transmitted infection, with more than 131 million new cases worldwide representing 20% of the STIs occurring annually (WHO). C. trachomatis infections are asymptomatic in up to 50% of men and 90% of women, so the majority of adults are unaware of the infection, and there is no vaccine available. Infection can result in infertility and ectopic pregnancy in women, and can lead to blindness in infants in developing countries due to trachoma. Prokarium is collaborating with Imperial College London on the evaluation of novel C. trachomatis vaccine candidates.