Vaccines Eligible for WHO Prequalification

Prioritization of vaccines guides decisions about where to focus limited prequalification resources but also supports national immunization programmes to achieve their goals.

Vaccines that are eligible for WHO prequalification are listed on the Vaccines Prequalification Priority List. Issued every two years the list categorizes vaccines that are anticipated to be available for supply before the end of the biennium according to four levels of priority: high, medium, low and no priority. See the boxes below for the vaccines priority list during 2018‒2020.

Priority categorization

The priority categorization of vaccines is established by the WHO in consultation with UNICEF and the Revolving Fund of the Pan American Health Organization. Both of these UN procurement agencies use the prequalification of vaccines service. Four criteria are used to determine the priority category for each vaccine:

  • demand in UN-supplied markets, including planned new vaccine introductions
  • suitability for WHO programmatic needs, in compliance with International Health Regulations, eradication, elimination or control initiatives and considerations of individual immunization programmes
  • recommendations of WHO’s Strategic Advisory Group of Experts on immunization
  • supply security, indicated by the number, diversity and production capacity of suppliers.

Supply security

Supply security is maintained by actively monitoring and responding to factors that can lead to shortages. These factors may include issues with production, such as batch failures and other risks linked to complex biological products, or complex and long production processes, quality control procedures and tight production planning. Supply may also be affected by the limited supplier base for some products due to significant barriers to market entry, or supplier decisions based on product and market attractiveness (e.g. profitability and certainty).