Assessing safety and immunogenicity of post-exposure prophylaxis following interchangeability of rabies vaccines in humans

Rabies post exposure prophylaxis with cell culture vaccines by either intramuscular route or intradermal route spans over a period of one month. World Health Organization recommends completing post exposure prophylaxis against rabies with the same cell culture or embryonated egg rabies vaccine and with same route of administration and any deviation from this shall be an exception. In the present study, the safety and immunogenicity of rabies post-exposure prophylaxis was studied prospectively in 90 animal bite cases that had interchangeability of rabies vaccines either by route of administration or brand/type and such changes had occurred due to logistical/financial problems. Among them, 47 had change in route of administration from intramuscular to intradermal or vice versa and 43 had change in the brand/type of cell culture rabies vaccine. All of them had category III rabies exposure and received equine rabies immunoglobulin along with the rabies vaccine. None of the study subjects had any adverse reactions. The rabies virus neutralizing antibody titers was assessed by rapid fluorescent focus inhibition test and all the vaccinees had titers ≥0.5 IU per mL on day 14 which is considered as adequate for protection against rabies. Thus, the present study showed that, rabies post-exposure prophylaxis was safe and immunogenic despite changes in the route of administration and brand/type of rabies vaccine.

Safety and Immunogenicity of purified chick embryo cell rabies vaccine (VaxiRab N) administered intradermally as post exposure prophylaxis

The affordability to rabies vaccine for intramuscular administration in post exposure prophylaxis is a major constraint. Therefore, in countries, where there are financial constraints, World Health Organization recommends intradermal rabies vaccination that reduces the quantity and cost of vaccination. This study was done to evaluate the safety and immunogenicity of indigenously developed rabies vaccine (VaxiRab N) in comparison to a WHO recommended rabies vaccine (Rabipur) with demonstrated efficacy when administered by intradermal route using updated Thai Red Cross regimen. Eighty-six dog bite cases were randomly given either VaxiRab N (n = 43) or Rabipur (n = 43) as post exposure prophylaxis. The rabies virus neutralizing antibody concentrations on days 14, 28, 90, and 180 were tested by modified rapid fluorescent focus inhibition test. The geometric mean RVNA concentration of both the groups were compared using t- test and was found that, P value > 0.05 on all days, thus showing no significant difference between the 2 groups. The adverse drug events were also compared using Z-test and was found to be not statistically significant (Z = 1.476, P = 0.139). In conclusion, VaxiRab N was found to be safe and effective in post exposure prophylaxis by intradermal route and was similar to the WHO recommended rabies vaccine (Rabipur) of demonstrated efficacy.

Pre-exposure prophylaxis against rabies in children: safety of purified chick embryo cell rabies vaccine (Vaxirab N) when administered by intradermal route

Animal bites in humans are a public health problem. Children are the most frequently exposed, representing 50% of human exposures in canine rabies infected areas. Pre-exposure vaccination using cell culture vaccines is a safe and effective method of preventing rabies among children in these highly endemic regions. The development of immunological memory after pre exposure vaccination has established long lasting immunity against rabies in humans. The present study assessed the safety of Purified Chick Embryo cell Rabies Vaccine (Vaxirab N) administered as a three-dose intradermal pre-exposure regimen on days 0, 7, and 21 in healthy volunteered children of 5-10 y age group from an urban poor locality in Bangalore, India. One hundred fifty three apparently healthy children of both sexes between 5 and 10 y of age were enrolled in the study and 123 (80.4%) completed all three doses. A total of 405 doses of intradermal vaccine was administered, among which 25 adverse reactions were reported from 17 children. The adverse reactions were pain at the injection site 15 (3.7%), redness 2 (0.5%), itching at the site of injection 1 (0.2%), fatigue 1 (0.2%), fever 3 (0.7%), myalgia 2 (0.5%) and allergy 1 (0.2%). All reactions subsided without any complication. In conclusion, pre exposure vaccination against rabies is a useful tool for protecting children living in highly endemic regions and Vaxirab N has proved to be safe and well tolerated by intradermal route among children.