The DRAFT WHO Plague vaccine Target Product Profile (TPP) has been developed with a group of experts in plague epidemiology, vaccine experts, and public health experts. The intent of WHO TPPs is to provide early technical guidance into the various product specific vaccine TPPs that are developed by individual vaccine manufacturers.
Currently, WHO does not recommend immunization with old-generation plague vaccines1. The recrudescence of plague outbreaks, the availability of new vaccine technologies, and biodefense concerns, have triggered renewed interest towards the development of new-generation plague vaccines. Furthermore, the need for a plague vaccine is also underscored in areas where plague infections may occur but where timely access to diagnosis and treatment is not guaranteed (e.g., remote rural areas, resources-limited settings, conflict areas, etc.). The WHO mapping tool currently registers 17 plague vaccine candidates under development, by private and public-sector laboratories. Two of these candidates have completed a Phase 2 clinical trial, and several candidates have plans to enter clinical trials in 2019. A WHO Plague vaccine Target Product Profile (TPP) was developed to provide aspirational guidance to vaccine developers. The TPP is informed by regulatory expectations, by technological feasibility and to consider both a preventive and a reactive scenario when using a Plague vaccine.
On April 23, 2018, WHO convened a group of about 30 experts in epidemiology, regulatory, preclinical and clinical vaccine trials, and mathematical modelling, in a workshop on planning for plague vaccine efficacy trials. The workshop aimed to define generic principles on how to best design, conduct and analyse vaccine trials against plague, based on the available scientific evidence as well as on lessons learned from the public health response to plague outbreaks.
Participants reviewed available evidence on plague epidemiology and vaccine candidates, identified and discussed methodological options to evaluate vaccines, regardless of vaccine products, and agreed on some preliminary recommendations. The WHO Plague vaccine TPP was expected to help inform vaccine evaluation decisions during the workshop.
It was recognised that the preliminary recommendations are likely to evolve as new evidence is generated, and also, they must be tailored to the social and cultural context of affected communities.