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Project

Evaluation of simplified alternative pre-exposure rabies vaccination schedules

Rabies is one of the neglected tropical diseases prioritized by WHO and it is the infectious disease with the highest case-fatality rate. The human death toll is highest in Asia and Africa, with invariably fatal encephalitis in at least 59.000 cases yearly. In literature, pre-exposure intradermal vaccination for rabies has proven to be as effective for pre-exposure and post-exposure prophylaxis as intramuscular vaccination. Intradermal administration of these vaccines offers an equally safe and immunogenic alternative, yet requires less vaccine antigen content. Intradermal regimens have been successfully introduced for pre-exposure prophylaxis in countries such as Thailand, Canada and the Netherlands. Nevertheless, with a schedule of 3 injections in 1 month, time is often lacking to give vaccination before travel: a schedule of 1 week or one day is less time consuming, and improves compliance. Three publications from one single group in Thailand for pre-exposure immunization suggest that an accelerated schedule of three intradermal injections within 1 week interval is as effective and immunogenic as administered within 4 weeks (1-3). They suggest also that one clinic visit with 2 sites 0.1 ml intradermal injections or a one-site 0.1 ml pre-exposure rabies vaccination is enough to prime the host immune memory for at least one to three years. These studies included only small subject patient populations. The outcome of this study is interesting for travellers to rabies endemic regions. The travel market of last minute holidays and trips to remote areas has expanded enormously. Until now, travelers in Belgian Travel Clinics are still vaccinated via intramuscular way. Frequently, there is not enough time before departure or practical problems arise to complete the schedule of 1 month; thus an effective schedule of 7 days or even one day would be very practical. Also Belgian Travel Clinics are recurrently encountering problems with the preparation time linked to rabies vaccines, and could profit from accerelated schedules with a one visit prime strategy. In addition to its applicability in travel medicine, the urgent need of upscaling a simple PrEP strategy in infants and children in at risk countries has been repeatedly endorsed in WHO guidelines, scientific literature and by policy makers, but actions are so far virtually non-existent in low income countries (LIC). By providing more relevant and powered data in adults (soldiers), the evidence for using simplified and low-cost intradermal rabies pre-exposure vaccination schedules has the potential of dramatically changing current WHO guidelines (Strategic Advisory Group of Experts (SAGE)) and national policies for disease management and prevention in LIC. For all these reasons, shortened, simple, acceptable, immunogenic and economical regimens which are compliant with the WHO requirements on vaccination, would be preferable over the classical vaccination schedule.

References: Khawplod P et al. Immunogenicity study of abbreviated rabies preexposure vaccination schedules. J Travel Med. 2007 May-Jun;14(3):173-6. Khawplod P et al. One or three intradermal injections within one week for rabies pre-exposure immunization. Dev Biol (Basel). 2008;131:393-401. Khawplod P, Jaijaroensup W, Sawangvaree A, Prakongsri S, Wilde H. One clinic visit for pre-exposure rabies vaccination (a preliminary study). Vaccine 2012; 30: 2918-20.
Date:24 Apr 2017 →  26 Jun 2020
Keywords:B780-tropical-medicine