RESUMO
To analyze the current global situation with respect to vaccine quality and to monitor progress in attaining it, it is first necessary to define what this means. While acknowledging that manufacturers are responsible for the quality of the vaccines they produce, World Health Organization (WHO) proposes a definition for "vaccines of assured quality" which depends on the existence of a competent and fully functional regulatory authority as assessed by an external expert team using widely agreed indicators to regulate the product. A vaccine of assured quality is defined as one that consistently meets appropriate levels of purity, potency, safety and efficacy as judged through an independent review system competent to take an evidence-based decision on the product for a specified population in a specific context. Such a review system would make use of all available information, such as licensing dossiers, surveillance of field performance, lot-by-lot scrutiny, appropriate laboratory testing, cGMP inspection of manufacturers, and evaluation of clinical trials, generally assumed by a fully functional regulatory authority. This definition implies that, faced with the same risk/benefit, any competent group would come to the same decision. The definition also indicates clear pathways to improve vaccine quality by strengthening national regulatory authorities and WHO is actively engaged in this task. By insisting on competent regulatory oversight, while recognizing the role of risk analysis in the selection of vaccines for use, WHO strongly reiterates the need for a single standard of quality. Only vaccine of assured quality should be considered for use in national immunization programs on the basis of the risk/benefit ratio for the particular population.