WHO Preferred Product Characteristics
The concept of the WHO Preferred Product Characteristics (PPC) is to drive the best early stage research to develop new products or improve existing ones in a highly strategic way to meet the public health need focusing in particular on low and middle income countries.
The PPCs start with review of an unmet public health need for which WHO seeks vaccine development. This includes a review of the WHO priority indications, with a particular focus on low and middle income countries, target groups, possible immunization strategies (sometimes including guidance on possible schedules), and clinical data desired related to safety and efficacy including endpoints and case definitions.
When WHO develops a pathogen specific PPC, it will include new guidance only on the public health aspects that are included in manufacturers' Target Product Profiles (TPPs). Each PPC addresses early stage vaccine R&D generally at least 5-10 years from vaccine availability, and will be reviewed and updated if necessary at least every 5 years. PPC are not static exit criteria, but are structured in such a way so as to drive innovation for early stage products to harness public health needs.
Guidance on physical characteristics including presentation and packaging (VPPAG, PSPQ)
Low and middle income countries (LMIC) face specific challenges in their immunization programs. Weak infrastructure, unreliable roads and electricity and remote populations all make delivering vaccines safely a significant challenge. While work is underway to improve the country systems themselves, there is also a need to ensure that the vaccines delivered in these countries are designed with their specific constraints in mind.
Consequently, there are important linked WHO processes that manufacturers should be aware of for presentation, packaging, thermostability, formulation and disposal. In all of these areas, WHO's LMIC member states have faced barriers related to supply, storage or administration because manufacturers have not adapted high income country presentations to the needs of LMIC.
Manufacturers are therefore referred to the following two key WHO initiatives in this area:
- the Vaccine Presentation and Packaging Advisory Group (VPPAG), convened by WHO and UNICEF, provides the possibility of interactions and consensus between the public and private sectors on questions related to presentation and packaging;
- the WHO Prequalification program’s Programmatic Suitability for Prequalification (PSPQ) process is a set of criteria against which any vaccine submitted for WHO PQ will be reviewed. Manufacturers should be aware of these criteria, several of which are ‘mandatory’ or ‘critical’ in order for a vaccine to be pre-qualified.
- Programmatic suitability for prequalification website
Programmatic suitability for prequalification document
While PPCs are pathogen specific, the PSPQ document is generic and there is also an available generic product profile developed by VPPAG which speaks to presentation and packaging issues.
Thus when taken together, PPCs, VPPAG and PSPQ provide WHO guidance covering many aspects of TPPs. If manufacturers follow this guidance they will be more likely to receive a favourable outcome from WHO recommendation and PQ processes once products are at the submission stage, and may advance product availability by many years.
The first WHO PPC will be to guide development of second generation malaria vaccines (target date for availability Q1 2015), a high priority given the ongoing deaths of greater 600,000 each year, the majority of whom are children under 5 in LMIC.
WHO is strategically prioritizing other pathogen areas for PPCs based on disease burden (often predominantly focused on LMIC), the likelihood of a vaccine product emerging in the mid term, and the role for WHO guidance in a given pathogen area.