Abstract
The global network of fridges and freezers known as the “cold chain” can account for a significant proportion of the total cost of vaccination and is susceptible to failure. Cost-efficient techniques to enhance stability of vaccines could prevent such losses and improve vaccination coverage, particularly in low income countries. We have previously reported a novel, potentially less expensive thermostabilisation approach using a combination of simple sugars and glass micro-fibrous matrix, achieving an excellent recovery of vaccines after storage at supraphysiological temperatures. This matrix is, however, prone to fragmentation and currently not suitable for clinical translation.
Here, we report an investigation of alternative, potentially GMP compatible, fibrous matrices. A number of commercially-available matrices permitted good protein recovery, quality of sugar glass and moisture content of the dried product but did not achieve the thermostabilisation performance of the original glass fibre matrix. We therefore further investigated physical and chemical characteristics of the glass fibre matrix and its components. Our investigation shows that the polyvinyl alcohol present in the glass fibre matrix assists vaccine stability. This finding enabled us to develop a custom-produced matrix with encouraging performance, as an initial step towards a biocompatible matrix for clinical translation. We discuss the path to transfer of the technology into clinical use, including potential obstacles.
Footnotes
Funding This work was supported by the UK Medical Research Council (grants MR/P017339/1 and MC_PC_15040), the UK Biotechnology and Biological Sciences Research Council (BB/M019152/1), and the UK Engineering and Physical Sciences Research Council (grant EP/R013756/1). ADD is supported by the Wellcome Trust (grant 201477/Z/16/Z) and is a Jenner Investigator. AVSH is supported by a Wellcome Trust investigator award (104750/Z/14)) and is a Jenner Investigator. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests AVSH and ADD are named inventors on patents relating to adenovirus-vectored vaccines.