Formulation developed to stop vaccine freeze damage
The work, details of which have been published in Vaccine volume 27, issue 1, was performed in conjunction with researchers at the University of Colorado.
By adding a small amount of freeze-protection stabilisers, such as glycerin, polyethylene glycol 300, or propylene glycol, to vaccines containing aluminium adjuvants damage from freezing was prevented.
The freeze-protection stabilisers have previously safely been used in human medications and PATH believes they can also be applied to vaccines for hepatitis B, diphtheria, tetanus toxoid and pertussis.
PATH has performed laboratory and preclinical studies with the formulations and has now placed the technology in the public domain so that vaccine manufacturers can use it.
There are currently two vaccine producers working to incorporate the technology into their formulations and PATH hopes others will also adopt the process.
By utilising the technology PATH believes that vaccine manufacturers can ensure that vaccines are fully potent when administered. In addition the technology could help reduce waste as vaccines are thrown away when health workers suspect they have been exposed to freezing.
PATH identified damage from freezing as a problem after reviewing 25 published and 10 unpublished articles on cold-chain transportation and storage of vaccines in developed and developing countries.
These studies found that vaccines are frequently subjected to temperatures below freezing despite the World Health Organization recommending all vaccines, except oral polio, are stored at 2°C to 8°C.