This report presents the recommendations of a WHO Expert Committee commissioned to coordinate activities leading to the adoption of international requirements for the production and control of vaccines and other biologicals and the establishment of international biological reference materials. The report starts with a discussion of general issues brought to the Committee's attention and provides information on the status and development of reference materials for various antibodies antigens blood products and related substances cytokines growth factors and endocrinological substances. The second part of the report of particular relevance to manufacturers and national control authorities contains recommendations for the production and quality control of inactivated influenza vaccine recommendations for the production and quality control of pneumococcal conjugate vaccines guidelines on regulatory expectations related to the nonclinical evaluation of vaccines an addendum to the recommendations for production and quality control of diphtheria tetanus and pertussis vaccines and an addendum to the recommendations for the use of animal cells as in vitro substrates for the production of biologicals.