Immunization standards

Vaccine reference preparations

"To define an internationally agreed unit to allow comparison of biological measurements worldwide"

WHO provides Biological Reference Materials which serve as reference sources of defined biological activity expressed in an internationally agreed unit. These preparations are the basis of a uniform reporting system, helping physicians and scientists involved in patient care, regulatory authorities and manufacturing settings to communicate in a common language for designating the activity or potency of biological preparations used in prophylaxis or therapy, and ensuring the reliability of in vitro biological diagnostic procedures used for diagnosis of diseases and treatment monitoring.

This concept of using well-characterized preparations as references against which batches of biological products are assessed remains fundamental to ensuring the quality of biological products as well as the consistency of production and are essential for the establishment of appropriate clinical dosing. These preparations are generally intended for use in the characterization of the activity of secondary reference preparations (regional, national or in-house working standards). They are made for use in laboratory assays only and should not be administered to humans.

Establishment of WHO Reference Materials

The WHO Biological Reference Materials are established through a standard procedure, found in TRS 932, Annex 2, in which representative materials (often one of several candidates donated to WHO for the purpose) are tested by participating laboratories using their own methodologies. These scientific studies are designed and coordinated by a responsible WHO Collaborating Center. Upon establishment of the reference preparation by the ECBS, the material is assigned a unitage, often in International Units, and serve as the comparator against which results from laboratories, regardless of location or methods employed, can be standardized and compared.

Distribution of WHO Reference Materials

WHO biological reference materials are often in limited supply, and only distributed to qualified laboratories. These include National Control Laboratories and manufacturers of biological medicinal products. The materials are distributed through custodians, which are generally one of the WHO Collaborating Centers. A small handling fee is usually charged by the custodian to offset the costs of international shipments.

Catalogue of WHO Biological Reference Materials

The WHO biological reference materials are listed according to product class, along with identification numbers and custodians.




  • WHO Working Group meeting on Respiratory Syncytial Virus (RSV) Vaccine Standardization, WHO headquarters, Geneva, Switzerland, 13-15 September 2017
  • WHO Second Working Group Meeting on Developing WHO Guidelines on safe production of polio vaccines, WHO HQ Salle D, 19-20 September 2017
  • WHO Workshop on Implementation of Good Manufacturing Practices for Biological Products, Bangkok, Thailand 15-17 November 2017
  • WHO Implementation Workshop on the Quality, Safety and Efficacy of Typhoid Conjugate Vaccines, Osong, Chungju-si, The Republic of Korea, 21-13 November 2017