Comparative evaluation of immunogenicity, reactogenecity and safety of purified chick embryo cell rabies vaccine and neural tissue rabies vaccine.

OBJECTIVES: 1. To compare the protective antibody titres on day 14, 30 and 90 after giving intramuscular (IM) injections of PCECV and subcutaneous injections of Nervous Tissue Vaccine. 2. To compare the immunogenicity and safety of PCECV and NTV. METHODS AND MATERIALS: The study enrolled cases in three groups.Group 'C' or control group: (n = 38) : This group comprised of 38 normal healthy volunteers without dog-bite. Group 'A' (n = 102): This group included cases of dog-bite fulfilling inclusion/exclusion criteria. Each one of Group A and C were given PCECV as post exposure treatment (PET) on day 0-3-7-14-30 and 90. Group 'B' (n = 50): This group included 50 cases of dog-bite who received NTV. The rabies virus neutralizing antibody titres were estimated by RFFIT (Rapid Fluorescent Focus Inhibition Test) on day 0, 14, 30 and 90 days. 45 recipients of PCECV were re-tested for persistence of Protective Antibodies at the end of 1 year. RESULTS: Of these 37, 91 and 45 cases were evaluable in Groups C, A and B respectively. The antibody titres in Groups A, B, C were 13.4, 3.2, 22.8 IU/ml respectively; the protective titre being 0.5 IU/ml.5% PCECV recepients had delayed response on day 30.14% of NTV recepients did not seroconvert. CONCLUSIONS: The Immunogenicity, Reactogenicity and safety of PCECV is well established. 5% of PCECV receipients showed a delayed sero conversion. 14% of NTV receipients did not sero convert at all.Therefore it is desirable to estimate antibody titres on day 14 after vaccination. If difficult, then all the cases of animal bite must receive passive immunization with rabies immunoglobulins.

Immunogenicity of purified chick embryo cell anti-rabies vaccine in post-exposure treatment of animal bite cases.

The observations on immunogenicity of Purified Chick Embryo Cell (PCEC) anti rabies vaccination in post-exposure prophylaxis is reported. In total 207 serum samples collected from patients receiving 3 to 6 doses of PCEC were analysed for the presence of anti-rabies antibodies. The samples were collected from 10 days to 11 months after the last dose of vaccine. All the vaccinees (n=33) tested after 3 doses of PCEC showed protective titres (> or = 0.5 IU/ml) and those receiving 5-6 doses (n=161) showed 4-5 times higher than protective titres. The analysis pertains to specimens collected at one point of time only after the vaccination. However, in all 17 vaccinees where samples were collected 7-11 months after 3-6 doses of vaccine, the protective titres were sustained, these being 3-4 times higher than the protective titres in those receiving 5-6 vaccine doses. The results indicated that there was no need of routine anti-rabies antibody monitoring in healthy individuals receiving post-exposure prophylaxis in recommended doses of vaccine.

Immunogenicity and feasibility of purified chick embryo cell vaccine.

Two hundred seventy-one children reported at the WHO Collaborative Centre for Rabies Epidemiology for South-East Asia at National Institute of Communicable Diseases, Delhi, for advice and antirabies antibody assessment after post-exposure prophylaxis with purified chick embryo cell (PCEC) antirabies vaccine from January 1986 to October 1992. Vaccine was very well tolerated by these children and only 7% complained about mild to moderate side reactions like pain, induration, fever or rash. On an average, every year 50-55 children had reported at this Centre after post-exposure vaccination with PCEC vaccine excepting years 1986 and 1987. One hundred and forty-four children underwent complete course of post-exposure prophylaxis, i.e., 5 or 6 doses on day 0, 3, 7, 14, 30 and 90 (optional) of PCEC vaccine were administered, forty-three (43) children received 4 doses on day 0, 7, 14 and 30 (day 3 dose was omitted) and eighty-four (84) children received 2 to 3 doses as the biting animals were alive for 10 days in these cases. Two hundred and twenty-nine children (84.5%) were bitten by dogs and in 10%, the dog was proven rabid by laboratory examination of dog brain. One hundred and forty-nine (55%) had Class III bite. Serological response, i.e., antirabies antibody titre in all these children were satisfactory (> 0.5 IU/ml) with mean titre of 1.98 IU/ml irrespective of doses of PCEC vaccine administered. No vaccine failure was observed in this study.