The goal of post-market monitoring (PMM) is to collect information and operational feedback about product performance in immunization operating environments to:

• contribute information for the prequalification of appropriate products
• ensure that WHO endorsement of the performance, quality and safety of prequalified products remains valid
• identify opportunities to further improve and evolve prequalification standards and the range of prequalified products available for procurement for the national programmes of the Expanded Programme on Immunization.

By collecting information and feedback, PMM affords end users the opportunity to contribute to the development of appropriate standards for immunization products. Industry and manufacturers also benefit from this feedback as it provides them with information that can help them to produce products that better meet their customers’ needs.

WHO is currently working to enhance PMM activities in order to further support equipment performance and reliability and to help strengthen national immunization programmes.  

PMM roles

WHO, partners, product manufacturers and product users all play crucial and interrelated roles in PMM:

Manufacturers are:

• obliged to report complaints to WHO
• expected to ensure quality assurance and/or implement corrective and preventative actions, as needed as part of their quality system
• must report all complaints and performance issues as part of their annual review.

Product end-users:

• are actively encouraged to report failures and complaints and provide feedback to WHO
• must collect and compare product performance data from all available sources (e.g. supervision visits). 

WHO and global partners:

• are expected to maintain a robust and sustainable PMM system
• monitor and evaluate the PMM system to generate technical insights that inform product improvement strategies and interventions
• use findings from PMM data to improve specifications.

Provide feedback on a prequalified product

Performance feedback from product users and product manufacturers includes valuable information on equipment performance under field conditions.

WHO monitors and collates product performance data from a range of sources. This data:

• alerts WHO to any major product issues requiring re-evaluation and/or temporary suspension of prequalified status
• inform revisions to existing standards, including product specifications and product verification protocols
• helps to identify emerging vaccine transport, delivery or storage needs that are not yet (fully) met by existing products or devices.

Manufacturers’ role in collecting feedback on product performance and product defects

Product manufacturers and resellers are actively encouraged to collect user feedback, including positive performance reports and product defect reports, and to promptly communicate these reports to WHO.

In addition to collecting performance reports and product defect reports, manufacturers of prequalified products are required to analyse product performance information as part of the annual review of their products. This is also a requirement of the quality management system, as stipulated by the International Organization for Standardization. Manufacturer analysis of product performance as a part of the annual review means that the root-causes of technology issues or product defects can be identified and addressed.

Some product manufacturers also contribute performance data from product field-testing when this information is required inclusion in the product dossier submitted for prequalification. Field-testing is required for products that are safety-critical or to be used in high volumes, among other reasons.

Product user’s role in reporting product faults or performance issues

User feedback supplies valuable information on equipment performance under field conditions. WHO collaborates with national EPI programmes, UNICEF and WHO country and regional offices to obtain comprehensive field performance data. It also encourages product users to provide prompt feedback on product performance or any defects. Positive feedback is also welcome.

Improve products, support innovation

WHO also collaborates with national EPI programmes, UNICEF and WHO country and regional offices, and with product manufacturers, to obtain comprehensive insights into emerging transport, delivery or storage needs of national EPI operating context that are not yet (fully) met by existing products or devices.

Product users are strongly encouraged to provide input on these evolving needs, as well as suggestions or requirements for new product functions and features that will help to meet them. These new features and functions will contribute to development of new target product profiles (TPPs), which are key strategic documents outlining desirable product characteristics and that may become requirements in future.

TPPs are intended to stimulate further feedback and dialogue with product manufacturers about how product user needs should be met.

TPPs help to stimulate new product development and innovation by:

• improving or modifying an existing prequalified product or product type. This is the case when a TPP addresses a known technical or operational shortcoming based on field performance data. The TPP process invites feedback from stakeholders and manufacturers, leading to revision of existing performance specification and its companion verification protocol(s), followed by a further cycle of product development and prequalification.

• leading to development of an entirely new prequalified product or product type. The TPP attracts an initial response from stakeholders and manufacturers resulting in development of a new specification and verification protocol and a new cycle of product development and prequalification.