WHO Preferred Product Characteristics (PPCs) and Target Product Profiles (TPPs), published by IVB, are intended to encourage innovation and promote development of products for use in settings most relevant to the global unmet public health needs. PPCs and TPPs are product-agnostic, and describe preferential attributes pertaining to vaccine indications, target populations, use case(s) and immunization strategies, as well as preliminary consideration of data that should be collected for safety, efficacy and policy evaluation.

The primary target audience for WHO PPCs and TPPs is any entity intending to eventually seek WHO policy recommendation and prequalification (PQ) for their products.

WHO’s objective is to promote the development of vaccines with optimal effectiveness and suitability for use in LMICs, thereby maximising global vaccine impact. PPCs provide guidance as to WHO’s preferences for new vaccines in priority disease areas.  The intent of WHO PPCs is to help define the value proposition of LMIC markets for vaccines in development, and subsequently to inform class or product-specific Target Product Profiles.

Priority disease areas are identified by WHO’s expert Product Development for Vaccines Advisory Committee (PDVAC), according to three criteria:

• Substantial disease burden exists in low- and middle-income countries (LMICs),
• No vaccines or products currently exist, but product development is ongoing and the route to licensure appears to be technically feasible, and
• Licensure of and access to vaccines in LMICs may be accelerated by WHO engagement.

PPCs are not static criteria or guidance and may be updated as pertinent disease or product landscape information becomes available.

What does a WHO PPC typically contain?

• The strategic public health goals of the vaccine, i.e. defining the unmet medical need and describing how the vaccine could address it, from the perspective of LMIC within the context of the existing global disease burden and epidemiology, as well other available interventions. 
• A high level description of vaccine research and development considerations, including availability of established surrogate markers/correlates/disease models that may inform decision making at various stages along the product development pathway, and ultimately be relevant for a policy recommendation. 
• Where there is stakeholder alignment, PPCs may refer to the proposed clinical progression pathway to demonstration of vaccine efficacy, with reference to expected case definitions and primary and secondary endpoints.
• A table describing product attributes and their preferential characteristics.
• Increasingly, PPCs also contain guidance on characteristics pertaining to vaccine presentation, packaging, storage requirements and disposal, on the basis of WHO guidelines such as those described by the WHO Programmatic Suitability for Prequalification (PSPQ) criteria and the  Generic Preferred Product Profile for Vaccines.

The status of vaccine WHO PPC development

To date, PPCs have been developed and published for malaria vaccines, group A Streptococcus vaccines, group B Streptococcus vaccines, next-generation influenza vaccines, Respiratory Syncytial Virus (RSV) vaccines and monoclonal antibodies for passive immunization against RSV, Herpes Simplex Virus (HSV) vaccines, Enterotoxigenic E.coli (ETEC) vaccines, Shigella vaccines, gonococcal vaccines, HIV monoclonal antibodies and for both new tuberculosis (TB) vaccines and therapeutic tuberculosis vaccines.

Target Product Profiles (TPPs)

As with PPCs, WHO Target Product Profiles (TPPs), published by IVB, are intended to encourage innovation and promote development of products for use in settings most relevant to the global unmet public health needs. Unlike PPCs

The primary target audience for WHO TPPs is any entity intending to eventually seek WHO policy recommendation and prequalification (PQ) for their products.

What does a WHO TPP typically contain?

TPPs define a mandatory set of product attributes such as indication, target population, dosing regimen, duration of protection, route of administration, safety and efficacy requirements. They also include criteria pertaining to product presentation, storage and shelf life. They may contain additional optional criteria, such as vaccine platform, cost of goods and manufacturing scale, depending on the vaccine type and development status. 

PDR may engage in development of TPPs where there is an urgent public health need to expedited vaccine development, and rapid guidance is needed. In so doing, PDR aligns closely with the WHO R&D Blueprint Initiative efforts. As TPPs are often being developed as new data are emerging, they are typically updated more frequently than PPCs.

The status of vaccine PDR TPP development