Introduction: World Health Organization has recommended that in healthy persons with category III exposures, who receive wound care and rabies immunoglobulin infiltration, a vaccine regimen consisting of 4 doses administered intramuscularly on days 0, 3, 7, and 14 can be used as an alternative to the 5-dose intramuscular regimen.Objective: To assess the clinical safety and immunogenicity of rabies vaccine administered as 4-dose Essen intramuscular regimen for post-exposure prophylaxis.Methods: A non-randomized, comparative, controlled study was conducted at the anti-rabies clinic, KIMS Hospital and Research Center, Bangalore, India. The study subjects were divided into study group i.e., 4-dose intramuscular regimen, and control group i.e., 5-dose intramuscular regimen, and were given post-exposure prophylaxis. All subjects were followed for any adverse drug events. Rabies virus neutralizing antibodies was determined on day 14, 90 & 180 at the WHO collaborating center, NIMHANS, Bangalore, India to assess the immunogenicity.Results: The present study included 70 adult animal bite victims, 35 each in study group and control group. The incidence of ADEs was 7.8% in 4-dose Essen group and 7.0% in 5-dose Essen group;the difference between them was not significant (P > .05). Similarly, all the subjects in both the groups had protective antibody titers of ≥ 0.5 IU/mL (100% seroprotective) from day 14 till day 180; the difference between two groups was also not significant (P > .05).Conclusion: The 4-dose intramuscular Essen post-exposure prophylaxis regimen was found to be clinically safe and immunogenic.
Keywords: 4-dose Essen intramuscular regimen; immunogenicity; rabies; safety; vaccine.