Rabies neutralizing antibody level in immunosuppressed patients after receive of rabies post-exposure prophylaxis

Introduction: Rabies is a fatal disease and has a threatening risk for the public health. Immunosuppression is related to a wide variety of diseases. It is recommended that immunosuppressed patients receive the full post exposure vaccination, concerning that the immune response may be inadequate. The aim of this study is to determine the level of rabies neutralizing antibody in immunosuppressed patients after receiving rabies post-exposure prophylaxis. Consequently we assess the efficiency of antibody level in immunosuppressed patients admitted at Pasteur Institute of Iran. The study was performed at Pasteur Institute of Iran. Data related to immunosuppressed patients, doses of anti-rabies vaccine and serum, and level of rabies neutralizing antibody titer collected from the patients admitted to the Prevention and Treatment of Rabies Center, Department of Vaccination at Pasteur Institute of Iran, during 2008 to 2010. Subjects who received chemotherapy, immunosuppressive drugs, and chronic renal failure were included in this study. Results: Twenty two cases were evaluated. The Immunosuppressed state was related to cancer [in 8 cases], 4 cases of hematologic disorders, 6 cases of autoimmune disease, and 4 cases of chronic renal failure or kidney transplant. Mean age of 46.45 +/- 21.5 year. All cases received HRIG serum [human rabies immunoglobulin] plus PVRV [Purified Vero cell rabies vaccine]. The level of rabies neutralizing antibody was checked two weeks after the last dose of vaccine. Mean level of rabies neutralizing antibody was 12.07 +/- 6.72 IU/ml. All cases achieved minimum protective level of antibody which is = 0.5 IU/ml. The amount of the antibody level had no relation to age or kind of immunosuppressive disease of patients. Conclusion: It is recommended that Rabies-exposed immunosuppressed patients receive rabies post exposure prophylaxes. We have to be cautious about the cases who have not achieved the appropriate level of rabies antibody. Keywords: Post-exposure rabies prophylaxis, Immunosuppressed patients, Rabies neutralizing antibody

[Study on lasting immunity in previously treated persons against rabies and investigation of booster effect of Vero rabies vaccine]

Human rabies is preventable by prompt post-exposure prophylaxis. The total number of rabies vaccine doses administered during post-exposure prophylaxis is 5; given on days 0, 3, 7, 14 and 30. The aim of this study was to measure the durability of rabies neutralizing antibody in exposed persons treated 14-17 years ago and to investigate the effect of 2 boosters of rabies vaccine. This study was conducted in 2 phases. In phase 1 blood samples were taken from 100 rabies vaccine recipients 14-17 years after they had received the vaccine. In the 2nd stage of the studies 30 volunteers from the first phase of the study were divided into 2 groups of 15 subjects each; the first group was given 2 booster doses of the vaccine intra-dermally on days 0 and 3. In the 2[nd] group the 2 doses were administered through the intramuscular route; blood samples were collected 10 days after the booster doses. Rapid Focus Fluorescent Inhibition Test [RFFIT] was used for measuring the antibodies in both phases. The rabies neutralizing antibody was detected in the sera of all 100 individuals who had received the rabies vaccine, 85% of whom demonstrated titers ?0.5 IU/ml. In the groups who received the booster doses, serology results demonstrated higher rabies neutralizing antibody titers in persons who had received the two booster injections intradermally. This study confirms the persistence of rabies neutralizing antibody for at least 14 years after a full course of primary post-exposure prophylaxis; furthermore two booster inoculations of Vero rabies vaccine on days 0 and 3, given intradermally resulted in a sharp increase in the level of antibodies, indicating that two boosters could protect against rabies after a repeat exposure