WHO vaccines prequalification is a service for UN agencies and supports specific needs of WHO Member States’ immunization programmes with regards to vaccine characteristics such as potency, stability, presentation, labelling and shipping conditions. The main objective of vaccines prequalification is to ensure that vaccines used in immunization programmes are of assured quality, safe and effective. In support of this objective, vaccine manufacturers are inspected in order to assess that the vaccine complies with WHO recommendations for production and control, that it meets the UN tender specifications (which reflect the needs of the immunization programmes at country level), that the company has an adequate quality management system in place, and that the relevant vaccine is manufactured in compliance with WHO Good Manufacturing Practice. Other important aspects of the on-site inspection may include, but are not limited to, labelling, packaging, whether a post-marketing surveillance system is in place, vaccine vial monitor (VVM) implementation when required, and a stability programme.

Inspections are required for those manufacturers applying for the prequalification of new vaccines to be evaluated for purchase by United Nations agencies (full assessment) [link to vaccine full assessment page]. They are necessary as part of the initial evaluation, as follow-up to corrective actions taken by the manufacturer following WHO recommendations, and for reassessment purposes. They may also be deemed necessary as a result of complaints or reports of serious adverse events following immunization (AEFIs) if a quality problem is suspected. The NRA responsible for the manufacturer, is invited to assign one or two staff members to join the WHO team, usually as observers. A bilateral consultation meeting is held between WHO and the NRA, either at the beginning or the end of the inspection. The purpose of this meeting is to discuss regulatory aspects related to the vaccine/s in question.

National regulatory agencies (NRAs) play a vital role in WHO vaccines prequalification since they are responsible for regulatory oversight of vaccines manufactured within their jurisdiction. National control laboratories (NCLs) are also important partners since they carry out independent and random testing of vaccines under evaluation for prequalification and contribute to post-prequalification testing and to random testing programmes.

To the extent possible, Inspection Services may also rely on information gathered through on-site inspections performed by NRAs that meet the critical indicators established by WHO for vaccine prequalification purposes.

Other types of inspection

As well as initial inspections for vaccine prequalification, Inspection Services may also conduct:

• follow-up inspections of vaccine manufacturing sites: to verify that corrective and preventive actions have been implemented by the manufacturers
• routine surveillance inspections of vaccine manufacturing sites: to verify that they continue to comply with WHO Good Manufacturing Practice (GMP) and with information submitted to the dossier.
• special (for cause) inspections of vaccines manufacturing sites: focusing on the specific causes (complaint, AEFIs, etc.) that triggered the inspection.