Post-prequalification procedures ensure that WHO's endorsement of the performance, quality and safety of prequalified products remains valid.

Once a product has been prequalified, and as long as no serious complaints have been received from product users, it will maintain its prequalified status for up to 12 months, or the next scheduled annual review of products (whichever occurs first). (Product complaints can be submitted by completing a product complaint form.)

A manufacturer of a prequalified product must keep WHO fully informed about any changes made to the:

• product itself
• manufacturing process of the product
• manufacturing site of the product.

Suspension or withdrawal of prequalification status

Prequalified status may be suspended or withdrawn for one of several reasons :

• the manufacturing site has been modified in such a way that it no longer meets international norms and standards
• alteration(s) to the product negatively impact(s) product performance
• mandatory documents required for product prequalification renewal (e.g. licences and certifications) have not been provided
• reports from UN procurement agencies indicate poor or inconsistent product control
• functioning of the product in the field does not or no longer meets the relevant performance requirements
• the manufacturer goes bankrupt or enters into receivership.

In the case of minor concerns, the manufacturer will be requested to provide relevant information to WHO. If this is satisfactory, prequalified status will be reinstated.

In the case of major concerns, the product will be suspended from the database of prequalified immunization devices until the manufacturer either satisfies WHO that quality issues have been addressed, successfully retests the product in response to performance concerns, or voluntarily withdraws the product. Manufacturers have up to six months in which to address the ground(s) of suspension.