Safety and non-suppressive effect of a purified F(ab’)₂ equine rabies immunoglobulin in WHO category iii rabies exposed patients

Background: Early management of rabies post-exposure patients with rabies immunoglobulin [RIG] is highly recommended in WHO category III of rabies exposure. Equine rabies immunoglobulin [ERIG] is as economical and effective as compared to human rabies immunoglobulin [HRIG] but more affordable to patients in developing countries. Objective: To evaluate safety and suppressive effect of a F(ab’)₂ ERIG (VINRAB®) in WHO category III rabies exposed patients. Materials and Methods: Eligible patients received wound treatment, single dose ERIG around the wound and intramuscularly [IM], and 5-dose purified chick embryo cell [PCEC] rabies vaccine (Essen regimen, 1.0 ml IM on days 0, 3, 7, 14, and 28). Sera before immunization were tested for rabies viral neutralizing antibodies by RFFIT on days 0, 7, 14, and 28. The adverse reaction was monitored for 60 days. Results: The results showed on day 14, 100% of the patients had seroconverted without suppressive effect. No serious adverse reactions or immediate reaction were observed. Conclusion: The purified F(ab’)₂ ERIG is considered well tolerated and can be utilized in parallel with standard IM dose of the PCEC rabies vaccine.