Aim: To improve post-exposure rabies prophylaxis in developing countries

All human deaths from rabies are due to a failure of prevention. No failures of  combined pre- and post-exposure prophylaxis have been reported. Infection with a dog rabies virus is universally fatal in man, and is the cause of >95% of the human deaths. These mainly occur in Asia and Africa, where prophylaxis relies on emergency post-exposure vaccine treatment to induce immunity to neutralise the virus in the site of an animal bite, before the virus enters the nerves. At least ten million people are estimated to receive post-exposure prophylaxis annually.

The production of the outdated nervous tissue homogenate rabies vaccines, are gradually being stopped, but modern tissue culture vaccines are unaffordable or unavailable in many areas of developing countries. The cost of the standard 5 dose intramuscular vaccine regimen is prohibitive, but 60% of the vaccine can be saved by giving multiple small intradermal injections. Two such multiple-site post-exposure vaccine regimens are recommended by the WHO where money and/or vaccines are in short supply. Although their safety and efficacy of have been established over twenty years, they are used only for only 3% of vaccine treatments in Asia, and very rarely in Africa. Their widespread implementation is inhibited by practical and pharmaceutical problems. The Oxford Vaccine Group is evaluating the immunogenicity of a new simplified immunogenic 4-site economical intradermal post-exposure rabies vaccine regimen, which could overcome several of the difficulties, and has the potential for wider uptake, to include patients who remain untreated at present.

In addition, we are also using the rabies vaccine as a novel antigen to evaluate the timing of appearance of plasma cells, memory B cells and antibody in peripheral blood in a primary as opposed to a secondary immune response. This will help interpreting the immune response to immunisation in children or post-primary immunisation in adults, and development future vaccines.