Chlamydia trachomatis vaccine development - a view on the current challenges and how to move forward

Introduction Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the world. A licensed vaccine is not yet available, but the first vaccines have entered clinical trials. Areas covered We describe the progress that has been made in our understanding of the type of immunity that a protective vaccine should induce, and the challenges that vaccine developers face. We also focus on the clinical development of a chlamydia vaccine. The first chlamydia vaccine candidate has now been tested in a clinical phase I trial, and another phase I trial is currently running. We discuss what it will take to continue this development and what future trial setups could look like. Expert opinion The chlamydia field is coming of age and the first phase I clinical trial of a C. trachomatis vaccine has been successfully completed. We expect and hope that this will motivate various stakeholders to support further development of chlamydia vaccines in humans.