A prequalified vaccine will retain its prequalified status provided that:
- no reports of serious adverse events following immunization (AEFIs) are received from product users
- the manufacturer meets post-prequalification requirements.
In most cases, a product's prequalified status is withdrawn voluntarily by a manufacturer due to the discontinuation of production or commercialization. In this case, manufacturers must provide WHO with the end of shelf-life date of the last batch produced, in order to remove the product from the vaccines’ prequalification website once the shelf-life has expired.
In rare cases, prequalified status may also be withdrawn by the WHO pending further investigation, if the manufacturer:
- does not fulfil post-prequalification requirements
- does not provide mandatory documents and information required for annual review
- does not (fully) comply with the requirements and information requested for periodic product reassessment
or if:
- vaccine quality complaints from testing laboratories, or reports of serious AEFIs, are received by WHO.
In some cases that WHO decides to withdraw the prequalified status of a vaccine based on quality or safety issues communicated by product users or national regulatory authorities or national control laboratories. In most of these cases, a Prequalification Ad-hoc Committee will be convened and its advice requested.