Detailed Information On Rabies Vaccine Schedule

The rabies virus seems to become inaccessible to immune surveillance once it enters a neuron. Hence, the aim of rabies prophylaxis is to kill or neutralize the virus by chemical or immunological means at the site of inoculation before it enters neurons. No anti rabies virus drug has been developed to date. The rabies post exposure prophylaxis (PEP) thus includes urgent wound care and administration of reliable human rabies immune globulin (HRIG) and rabies vaccine. A recent study estimated 23,000 cases of potential rabies exposure in the United States per year warranting PEP. The latest Advisory Committee on Immunization Practices or ACIP human rabies PEP guidelines incorporating a 5-dose vaccine schedule were published in 2008. The same year, the ACIP formed a workgroup to review rabies vaccine regimen options in the United States.

Ranndomized controlled trials comparing different vaccine schedules have not been conducted because of the severity of the disease. In human studies, rabies virus neutralizing antibodies (surrogate marker for an adequate immune response to vaccination) are detectable by 7 to 10 days after initiation of vaccination and peak by 14 to 28 days, without any additive value of a fifth dose of vaccine administered on day 28.2 The so-called Zagreb regimen of 2-1-1, which uses 4 doses of the vaccine in total, 2 on day 0 on bilateral extremities, and subsequent doses on days 7 and 21, has been used successfully worldwide for many years and is recommended by the World Health Organization for PEP.

Besides, epidemiologic surveillance has failed to find any rabies cases among patients in the United States who received appropriate wound care, HRIG, and 4 doses of the vaccine instead of the recommended 5. None of the 27 human rabies cases reported in the United States between 2000 and 2008 had received any PEP before the onset of illness. Since the advent of routine use of rabies PEP incorporating HRIG and cell-culture vaccines, no case of failure of this regimen has been reported in the United States or in Western Europe. There have been very rare reports of failure of seemingly appropriate and prompt human PEP from developing countries, but no such case has ever been attributed to the lack of receipt of the fifth vaccine dose on day 28. Adequate PEP should also lead to sustained immunologic memory.

Indications for rabies pep

rabies vaccine injection

The prevalence of rabies in different animals varies from 25% in a skunk to 15% in a bat, 1% in a cat, and 0.1% in a dog. 12 A panel of experienced public health experts estimated the median risk of rabies transmission after bite exposures by skunk, bat, cat, and dog (where the animal escaped and was not available for testing, and the wound was not washed at the time of injury) at 0.05, 0.001, 0.001, and 0.00001, respectively.

Revised rabies pep recommendations for unvaccinated persons

rabies vaccination

In unvaccinated persons, a bite or nonbite exposure to rabies should be followed by immediate wound care and administration of HRIG as well as vaccine. The PEP regimen remains the same irrespective of the patient’s age and the time interval between exposure and its initiation. The regimen should ideally begin as soon as possible after exposure. The date of the first dose of the vaccine is considered day 0. Subsequent doses should be given 3, 7, and 14 days after the first dose. The vaccine dose is the same irrespective of patient’s age. The vaccine should be administered IM in the deltoid area of the arm to adults and children 2 years or older. Anterolateral aspect of the thigh is recommended for younger children.

4-Dose Vaccine as Post-exposure Prophylaxis

not be mixed in the same syringe as the vaccine for IM administration and should not be administered at the same site as the first dose of the vaccine. In case of multiple wounds, HRIG may be diluted 2- to 3-fold in saline to a volume sufficient to infiltrate all wounds effectively

PEP recommendations for previously vaccinated persons

Human rabies immune globulin is not indicated for this group. Two booster vaccine doses should be administered, on days 0 and 3.9.

PEP recommendations for immunosuppressed persons

Because of the potential suppression of immune response, a 5-dose vaccine series Von days 0, 3, 7, 14, and Vis recommended. Immunosuppressive medications should be withheld during PEP unless essential. Serum samples should be tested for neutralizing antibody 1 to 2 weeks after completing the vaccine series to ensure an acceptable response. In the absence of this response, assess the need for an additional dose of the vaccine and consult appropriate public health officials for further individualized advice.