Vaccine Delivery Technologies
The need for thermostable vaccines
Vaccines are temperature sensitive and most of the currently available vaccines (such as the vaccine for measles, mumps, pertussis, tetanus, influenza, etc) must be stored between 2ºC and 8ºC. Exposure to high or very low temperatures causes rapid loss of bioactivity. Maintaining the cold chain increases the cost of immunisation by 14% (source: WHO), but most importantly vaccine damage as a result of cold chain breakages costs human lives.
This challenge is particularly acute in mass vaccination programmes in developing countries where high ambient temperatures and lack of infrastructure to support a reliable cold-chain leads to vaccine wastage rates of 25-50%. Only in 2007, 151 million vaccine doses were wasted (source: Gates Grand Challenges).
Thermal stabilisation of vaccines has been identified as one of the much-needed technologies capable of transforming immunization programmes in the 21st century and is seen as a strategic priority for the WHO, GAVI, PATH and Bill and Melinda Gates Foundation.
Sugar preserves vaccines without refrigeration
A simple and cheap way of making vaccines stable – even at tropical temperatures – has been developed by the scientists at the Jenner Institute, Cambridge Biostability Ltd and Nova Bio-Pharma Technologies. The technology involves mixing the vaccine with the sugars trehalose and sucrose. The mixture is then left to slowly dry out on a simple filter or membrane. As it dries and the water evaporates the vaccine mixture turns into a syrup and then fully solidifies on the membrane. The thin sugary film that forms on the membrane preserves the active part of the vaccine in a kind of suspended animation, protected from degradation even at high temperature. Flushing the membrane with water rehydrates the vaccine from the membrane in an instant.
The research article can be found here.
The technology is also described in a BBC programme - Frontiers: Future Vaccines.
The future
Harnessing this thermostabilising technology for field-usable vaccines is the next goal of the work programme at the Jenner Institute. The World Health Organisation’s immunisation program vaccinates nearly 80% of the children born today against six killer diseases: polio, diphtheria, tuberculosis, whooping cough, measles and tetanus. One of the biggest costs is maintaining what’s called the cold chain – making sure vaccines are refrigerated all the way from the manufacturer to the child, whether they are in the Western world or in the remotest villages in Africa. If most or all of the vaccines could be stabilised at high temperatures, it would not only remove cost, more children would be vaccinated.
We welcome opportunities for collaboration or business partnership; enquiries can be directed to Dr Migena Bregu.
Email: migena.bregu@ndm.ox.ac.uk
Tel: +44 (0)1865 617628
Group members
Prof Adrian Hill, Scientific Supervisor
Dr Matt Cottingham, Scientific Investigator
Dr Migena Bregu, Project Manager
