Comparison of Immune Responses following Intradermal and Intramuscular Rabies Vaccination Methods

Rabies is a zoonotic viral disease. The causative agent is a negative-sense RNA genome virus of the genus Lyssavirus (Family: Rhabdoviridae). The disease, commonly transmitted by rabid dogs, is the cause of mortality of over 59000 humans worldwide annually. This disease can be prevented before the development of symptoms through proper vaccination even after exposure. Hence, improvement of the vaccination schedule in the countries where rabies is endemic is essential. In addition to the type of vaccine, injection routes also contribute to enhanced immune responses and increased potency of the vaccines. The vaccines approved by the World Health Organization (WHO) include cell culture and embryonated egg-based rabies vaccines (CCEEVs). In order to develop a vaccine against rabies, it is necessary to use an appropriate delivery system to promote a proper antigen-specific immune response. Different routes of injection such as intradermal (ID), intramuscular (IM) or subcutaneous (SC) are practiced, with controversies over their suitability. In this article, we discuss the immunological aspects of rabies vaccination by comparing ID and IM delivery systems.