Who Prequalification Vaccines Requirements

First, let`s go back to 1946, when the Constitution of the World Health Organization (WHO) was first adopted and signed before it came into force in 1948. According to Article 2 of the Constitution, part of WHO`s mandate is “to develop, establish and promote international standards for biologics such as medicines and vaccines”. To fulfill this mandate, WHO founded the Committee of Experts on Biological Standardization (ECBS) in 1947, which has met annually ever since. This is how in 1987 prequalification was born! WHO published its first requirements for vaccine prequalification, which focused on a review of production consistency and inspection of the production site(s) to ensure good manufacturing practices. While prequalification was originally a service provided by WHO only to UNICEF, it was eventually extended to all United Nations procurement agencies. A network of 12 laboratories worldwide ensures the testing needs of the program [36]. Independent analysis of vaccine samples remains a challenge, especially for new vaccines, where the expertise to perform the required tests falls to a very limited number of laboratories and, in some cases, is limited to the National Control Laboratory (NCL) of the producing country. Ensuring a minimum level of expertise worldwide to perform relevant tests independently of manufacturers remains one of the objectives of the prequalification program. A collaboration with the manufacturers was initiated to promote the establishment by transferring the methodology to at least one laboratory in addition to the NCL responsible for batch release. Further work has been undertaken to harmonize test methods between the different laboratories mandated by WHO where relevant. To help countries build appropriate regulatory capacity, WHO has developed a strategy to prioritize capacity building based on the essential functions of RNAs based on vaccine source (Fig. 1) [16]. This made it possible to focus on the most relevant features with limited resources.

In this context, countries purchasing vaccines through UN agencies have been advised to perform only two functions: marketing authorization and pharmacovigilance, including adverse events after vaccination (AEFI). The other four functions are carried out by the Prequalification System, which ensures continuous regulatory oversight by NRAs in the country of origin and compliance with WHO requirements, UN tender specifications and the specific needs of national immunization programmes in user countries. Some of these areas for improvement have been addressed by changes to the procedure as amended in 2010 [25] by introducing a simplified process for products originating in countries with experienced NRAs/NPLs, removing the testing requirement in cases where NLCs in these producing countries have confirmed production consistency through independent testing and accept: share their findings with WHO – by strengthening the monitoring of timelines for the implementation of the different stages of the process (through an internal monitoring tool), by promoting meetings between manufacturers and the WHO PPQ Secretariat before submissions and during evaluation, in order to improve communication and develop a common understanding of requirements and results. In addition, the Secretariat publishes items on the review of model documents to provide manufacturers with clear guidance on the PQ`s expectations in various areas or aspects of the process [38], [39], [40]. Three other documents are under preparation. These address important and topical topics: variations, validation of the manufacturing process and risk analysis in the event of deviations [unpublished]. Fast forward to 1974, when the WHO Expanded Programme on Immunization (EPI) began. Many countries procured (i.e. purchased) the first six EPI vaccines – diphtheria, pertussis (pertussis), tetanus, measles, polio and tuberculosis – through the United Nations Children`s Fund (UNICEF) Care Unit. One of the challenges for the ECB was to ensure that vaccines purchased from whom, UNICEF and other UN agencies met adequate standards of quality, safety and efficacy. Initially, this quality control was carried out through national vaccine testing or testing in WHO centres, but a more formal process eventually became necessary.

Table 1 compares the different versions of the prequalification process and shows its main features. It shows the changes that have been introduced over time from 1987 to the present day to strengthen and better align them with emerging needs and current regulatory trends and expectations [10], [21], [22], [23], [24], [25]. The objective of WHO vaccine prequalification is to ensure that vaccines used in immunization programmes are safe and effective. Prequalification also meets the specific needs of national vaccination programmes in terms of vaccine properties such as potency, thermal stability, presentation, labelling and shipping conditions. .