Introduction to PQS - Specifying, testing and pre-qualifying products for use in immunization programmes

Since the early days of EPI in the late 1970’s there has been a need for specialised cold chain equipment designed to meet the demanding performance requirements of the developing world, where fuel supplies and electrical power are limited and unreliable and climatic conditions are often challenging. In order to meet this need, WHO, in consultation with UNICEF Supply Division, drew up performance specifications and test procedures and collaborated with a small number of manufacturers and testing laboratories to develop a range of key products for the vaccine cold chain. Products that successfully passed the testing stage were listed in the WHO/UNICEF Product Information Sheets (PIS), the last paper edition of which was published in the year 20001. Over the years, the scope of the PIS was extended. Auto-disable syringes and lowcost waste management products have been introduced to help ensure that immunization injections are safe and that used injection equipment can be properly disposed of. Vaccine Vial Monitors (VVMs) have been developed so that the temperature exposure of individual vaccine vials can be monitored. After an extended overlap period, PIS has now been replaced by the PQS (Performance, Quality and Safety) system. The new system is designed to bring in a wider range of manufacturers, to introduce further new technologies and to meet the challenges posed by the introduction of a growing range of new and more expensive vaccines. The PIS document was a combination of product catalogue and buyer’s guide. PQS will perform the same functions, but information will be in electronic format so that it remains up-to-date. This document describes the scope of the system, how it is organised, how specification documents are written and amended, and how products are pre-qualified; it covers the annual review process, accreditation of test laboratories and outlines the content of the PQS website.