Post-Market Monitoring (PMM) is a crucial part of WHO IMD-PQS' work. It is mandatory for all Prequalification Holders to provide feedback on product performance and safety. The success of IMD-PQS post-market monitoring depends on Prequalification Holders and the wider immunization community to collect and share information and operational feedback about product performance in immunization operating environments to:

• contribute information for the prequalification of appropriate products
• ensure that WHO endorsements of the performance, quality and safety of prequalified products remains valid
• provide insight into the reasons for equipment failure, which can inform and improve IMD-PQS performance specifications and verification protocols
• ensure timely feedback to Prequalification Holders to enable corrective and preventative actions
• collect information that can be used to improve countries' vaccine management systems.

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

Reports of performance issues or failures will NOT automatically lead to the suspension of a products' prequalified status.

Prequalification Holders' role in collecting feedback on product performance and product defects

Prequalification Holders 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.

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

Product performance reports (complaints, defects and positive feedback) should be provided via the dedicated form: Complaints & feedback reporting form.

In addition to collecting performance reports and product defect reports, Prequalification Holders 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 (QMS), as stipulated by the International Organization for Standardization. Prequalification Holders' 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 Prequalification Holders 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 and evolving needs

Product end-users (national immunization programmes):

• 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)
• are strongly encouraged to provide input on the evolving needs of their operating contexts, as well as suggestions or requirements for new product functions and features that will help to meet them

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.

Feedback should be provided via the dedicate Complaints & feedback reporting form

WHO IMD has developed a Toolkit of resources to guide country stakeholders planning to implement PMM through the set-up and implementation of Sentinel Surveillance.

The TOOLKIT is available to download here.

WHO and global partners' role in supporting product improvement and innovation

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.

WHO collaborates with national EPI programmes, UNICEF and WHO country and regional offices and with Prequalification Holders, 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.

Input provided by product end-users (national immunization programmes) on their evolving needs, as well as suggestions or requirements for new product functions and features that will help to meet them, will contribute to development of new target product profiles (TPPs). TPPs are key strategic documents outlining desirable product characteristics and that may become requirements in future. Further information about TPPs is available here.