Vaccine lot release conducted by the regulatory authorities is part of the regulation of vaccines and involves the independent assessment of each individual lot of a licensed vaccine before it is released onto the market. This assessment is based, as a minimum, on the review of manufacturers' summary protocols. It may be supplemented by other documents such as the release certificate from the responsible National Regulatory Authority (NRA)/National Control Laboratory (NCL) and in some circumstances, by independent testing which is independent of the manufacturers' quality control (QC) testing. WHO provides support for lot release programs through provision of written and measurement standards, strengthening lot release function of the NRAs and providing training (1, 2, 3, 4).However, a need for further guidance was identified at WHO consultation held in Ottawa in 2007. This document provides recommendations and strategies for lot release of vaccines by the NRAs/NCLs of producing and procuring countries. It should be read in conjunction with the recommendations/guidelines for specific products (e.g., recommendations for BCG, OPV, MMR, DTP, HPV, and rotavirus vaccines etc.) (5, 6, 7, 8, 9, 10). Though it is difficult to provide a set of guidelines applicable to all national situations, an attempt has been made to cover a range of acceptable possibilities. Independent lot release involves the confirmation that each lot meets the specifications in the approved marketing authorization for the product. Under defined circumstances, laboratory testing by an NCL can provide added value to this confirmation. The need for testing should however be justified according to criteria as specified in this document and the laboratory should operate under an appropriate quality assurance system. When independent laboratory testing is undertaken, NCLs should ensure that it is conducted according to the principles defined in this document. Testing under inappropriate conditions may generate inaccurate data and lead to misleading decisions. This guideline also highlights the importance of networking and work sharing among NRAs/NCLs.The guideline is intended to serve as a guide for national requirements for lot release. If a national regulatory authority so desires, these guidelines may be adopted as definitive national requirements, or modifications may be justified and made by a national regulatory authority. It is recommended that modifications to the principles and technical specifications of these guidelines be made only on condition that the modifications ensure that the risks of introducing vaccines for use in public health programmes are no greater than as outlined in the guidelines set out below.
