WHO released WHO IVB 11.03: manual for the establishment of national and other secondary standards for vaccines. “Aimed primarily at staff of national control laboratories and vaccine manufacturers, this document contains guidance on the principles of the preparation of national or other secondary biological standards, and details the issues which should be considered in the preparation and calibration of such standards. http://www.who.int/immunization/documents/who_ivb_11.03/en/index.html

http://whqlibdoc.who.int/hq/2011/WHO_IVB_11.03_eng.pdf