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Page 12 Bote et al. One Health Implement Res 2023;3:11-5 https://dx.doi.org/10.20517/ohir.2022.46

Keywords: Rabies, post-exposure prophylaxis, intradermal vaccination schedule, One Health, neglected tropical
diseases, zoonoses

Rabies is a viral zoonotic disease that remains a significant - and deadly - public health problem in many
parts of the world. Rabies infection causes an estimated 59,000 human deaths each year, mainly in
underserved populations in Asia and Africa, and 40% of the victims are children under 15 years of age. In
rabies-endemic areas, contact with domestic dogs through bites or scratches is responsible for 99% of the
[1]
cases .
In 2018, the World Health Organization (WHO), the Food and Agriculture Organization of the United
Nations, the World Organisation for Animal Health and the Global Alliance for Rabies Control set the
[2]
global target of achieving zero human deaths from dog-transmitted rabies by 2030 (“Zero by 30”) . As
rabies is almost inevitably fatal as soon as symptoms appear, its prevention, both in humans and dogs, is key
to reaching this goal. Prevention requires providing post-exposure prophylaxis (PEP) to exposed
individuals, mass vaccinating susceptible dog populations to control the disease at its source, and increasing
community awareness and engagement in rabies control.

PEP consists of thorough wound washing for 15 minutes with copious amounts of water and soap, a series
of rabies vaccine injections, and, if indicated, the administration of rabies immunoglobulin or monoclonal
antibodies. Since Louis Pasteur’s first efforts in 1885, rabies vaccines have been greatly improved and
modern vaccines are highly immunogenic and well-tolerated. Most vaccines were initially developed for
intramuscular (IM) administration; therefore, the standard vial size corresponds with a single dose of IM
vaccine (either 0.5 or 1 ml, depending on the manufacturer). Depending on the chosen IM PEP regimen, at
least 4 doses of vaccine are needed. Though there are safe and effective rabies biologicals, especially in low-
income settings, rabies continues to kill those who cannot access healthcare timely and cannot receive
effective PEP, due to its unavailability or unaffordability. Expanding rabies PEP is a critical step in saving
lives and ending the burden of rabies. In 2018, GAVI, The Vaccine Alliance, decided to add rabies to their
vaccine investment strategy, paving the way for greater access to PEP worldwide .
[3]
As part of its commitment to the Zero by 30 goal, WHO works to provide rabies immunization guidance
intended to reduce barriers to the access to and delivery of PEP. In 2022, WHO published a new guide for
the introduction or expansion of rabies vaccination into national immunization programmes to
systematically drive down human rabies deaths effectively and cost-efficiently .
[4]

For exposed individuals who have not been previously immunized, WHO recommends a 1-week
vaccination schedule on days 0, 3 and 7. On each visit, the rabies vaccine is administered through 2-site
intradermal (ID) injections of 0.1 ml of vaccine each, preferably using an insulin syringe . This shortened
[5,6]
ID regimen is as efficacious as other established regimens since the antigen-presenting cells in the skin are
more effective than the same cells in the muscle, thus being able to trigger a high-immune response .
[7,8]
Moreover, one ID vaccination dose only requires 0.1 ml of vaccine per site allowing for one vial to be shared
among patients (subject to hygienically using a new syringe each time and properly maintaining the cold
chain). Once opened, vials need to be discarded after 6-8 hours. Before disposing of the open vial, it is
recommended to use the remaining vaccine for PrEP in animal and human health professionals at
occupational risk, or relatives or accompanying persons of exposed patients.