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The use of reference materials is the basis of standardization and quality control of biologicals such as vaccines produced by different manufacturers and lot-to-lot consistency. The aim of this study was to establish a secondary local and national reference standard of adsorbed tetanus toxoid that can be used for tetanus toxoid vaccine potency testing. Concentrated bulk of tetanus toxoid was adjuvanted and aliquoted before lyophilization. Lyophilized product was tested for biological and physicochemical qualities, including moisture content, identity, appearance, antigen content, degree of adsorption, and sterility. The potency of the candidate reference material was calibrated against the 4th World Health Organization International Standard (WHO IS) for tetanus toxoid by two independent laboratories (BioNet-Asia and Thai National Control Laboratory) using the WHO mouse challenge test. A total of 839 vials with lyophilized tetanus toxoid reference material were produced. Potency was estimated at 115 IU/vial [intra-laboratory geometric coefficient of variation (GCV) of 7 tests was 16.5%] and 112 IU/vial (intra-laboratory GCV of 5 tests was 38.6%) at the two laboratories, with an inter-laboratory GCV of 25.5%. The potency of the candidate standard was assigned a value of 114 IU/vial. The candidate reference standard was approved by The Thai National Central Laboratory (NCL) as the Thai national tetanus toxoid reference standard., Competing Interests: Declaration of competing interest Daraporn Pittayakhajonwut, Pannipa Ekthaicharern, Greanggrai Hommalai, Dissaya Lohavech, Rattana Jongkol, Indrajeet Poredi, and Nadir Harjee are employed by BioNet, the vaccine manufacturer that prepared the adsorbed tetanus toxoid bulk. The statement is made in the interest of full disclosure and not because the authors consider this a conflict of interest., (Copyright © 2020 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.)

In 2010, the WHO guidance document for the evaluation of cell substrates for producing biologicals was replaced with updated recommendations and in May 2013 an implementation workshop on the new recommendations was held in Beijing, China. As part of this workshop, a survey of the use and evaluation of cell substrates for producing biologicals was undertaken and the information obtained was updated in June 2014. The purpose of survey was to capture the status of national requirements related to cell substrates in various countries with particular emphasis on whether or not the updated WHO recommendations had been, or were to be, incorporated into national requirements. This paper reports the outcome of the survey and is based on information provided by regulators in eleven countries. Since the publication of the updated WHO recommendations, several activities such as the implementation workshop and publications have been undertaken by the WHO. The aim of these activities, including the publication of this article, is to contribute to the implementation of WHO recommendations so as to reduce regulatory gaps between national requirements and globally agreed expectations., (Copyright © 2015. Published by Elsevier Ltd.)