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ABSTRACTThis phase IV, single blind study assessed the immunogenicity and safety of India-manufactured purified chick embryo cell rabies vaccine (PCECV), compared with a German-manufactured batch obtained by the same production process. A total of 340 participants enrolled at 2 study sites in India were randomized (1:1:1:1) in 4 groups to receive a 5-dose Essen regimen with either 1 of the 3 Indian batches (PCECV-I) or the German batch (PCECV-G), administered on Days (D) 0, 3, 7, 14 and 30. The lot-to-lot consistency of PCECV-I batches in terms of induced immune response at D14 was demonstrated. The immune response elicited by PCECV-I was shown to be non-inferior to that induced by PCECV-G, as the lower limit of the 95% confidence interval for the ratio (PCECV-I/PCECV-G) of rabies virus neutralising antibody (RVNA) geometric mean concentrations was higher than 0.5 at D14. At least 96% of participants developed adequate RVNA concentrations (≥ 0.5 IU/mL) by D14 and all achieved RVNA concentrations ≥ 0.5 IU/mL by D90. RVNA levels were comparable across all groups throughout the entire study. Solicited local and general symptoms had a similar incidence in all groups. Unsolicited adverse events (AEs) were reported by 11% of participants. Only 1 serious AE (leg fracture) was reported and was not related to vaccination. No deaths and no rabies cases were recorded during the 90 days of observation. The study showed that the 3 PCECV-I and the PCECV-G batches induced a similar immune response and had a comparable safety profile when administered according to a 5-dose schedule.

ABSTRACTHuman rabies is a preventable disease through post-exposure prophylaxis (PEP) in rabies endemic countries where enzootic cycle of dog rabies occurs. The COVID‑19 pandemic has induced an unprecedented challenge for under-funded and already stretched health‑care systems particularly in low- and middle-income countries, which are unfortunately bearing a huge burden of human rabies. An analysis of hospital-based PEP data in India, Nepal, Sri Lanka, and Thailand, focus group discussion and key informant interview have been carried out to better understand the impact of Covid-19 pandemic in human rabies prophylaxis. It is necessary to better prepare for human rabies prophylaxis in future pandemics based on lesson learnt from current pandemic. The PEP should be categorized as an emergency medical service, and it should be part of the hospital medical emergency. Mass dog vaccination against rabies should be accelerated to reduce the risk of potential bite of roaming dogs and pet dogs in communities. It is a wise decision to invest in cost-effective preparedness, i.e., mass dog vaccination rather than costly response, i.e., human rabies prophylaxis.

Zydus Cadila Health care, India developed a new purified chick embryo cell rabies vaccine (PCECV, Vaxirab-N; 1 mL) by adapting Pitman–Moore strain of virus on to the chick embryo fibroblast cell line in 2006. During 2007–10, a series of safety and immunogenicity studies were conducted as per ICH-GCP guidelines after obtaining permission from Drug Controller General of India. In the first study, Vaxirab-N was administered to 35 healthy adult volunteers by intramuscular (IM) route using pre exposure regimen. The geometric mean concentration (GMC) of rabies virus neutralizing antibody (RvnAb) of 7.5 IU/mL on day 35. In the second study, Vaxirab-N was administered to 35 healthy adult volunteers using simulated post- exposure prophylaxis regimen by IM route. A GMC of 6.3 IU/mL on day 14, 13.2 IU/mL on day 28 and 8.6 IU/mL on day 90 was obtained. In the third study, Vaxirab-N administered by intradermal (ID) route using Updated Thai Red Cross (TRC) regimen in 36 healthy adult volunteers showed GMC of 7.8 IU/mL on day 14, 11.5 IU/mL on day 28 and 6.0 IU/mL on day 90. The 4th study was multi centric and Vaxirab-N was administered to 129 animal bite cases by IM route using post-exposure Essen regimen. The GMC following this schedule was 8.2 IU/mL on day 14, 13.01 IU/mL on day 28, 7.92 IU/mL on day 90 and 3.72 IU/mL on day 180. Mild to moderate adverse events were reported to Vaxirab-N but no serious adverse events were reported in any of these studies. In conclusion, Vaxirab-N developed by Zydus Cadila was found to be safe and immunogenic by both intramuscular and intradermal route and is recommended for rabies prophylaxis (CTRI No. 2010/091/000055 and 2010/091/000509).

Rabies continues to be a major public health problem in India. Nearly 17 million people are getting exposed to this disease every year. Therefore the need for effective post-exposure prophylaxis with safe and potent modern rabies vaccines continues to exist. Purified Duck Embryo Vaccine (PDEV) was introduced in this country to meet the ever increasing need for modern rabies vaccines. In this study we have assessed the safety, imunogenicity and tolerance of an indigenously manufactured PDEV in people exposed to dog and other animal bites. One hundred and fifty people (5-59 years) who were having WHO category II or III animal bites were vaccinated with PDEV using the Essen Intramuscular regimen and rabies immunoglobluin (RIG) was administered to category III exposures.. Their blood samples were analyzed for rabies virus neutralizing antibody response (RVNA) by Rapid Fluorescent Focus Inhibition Test (RFFIT) on day 0, 14, 30, 90, 180 and 365. Adverse effects to vaccines were monitored during the course of vaccination. There was 100% sero- conversion from day 14 onwards with adequate RVNA titers ( >= 0.5 IU/mL) up to day 365. The incidence of side effects was minimal and self limiting. Hence it can be concluded that indigenously manufactured PDEV (Vaxirab) is a safe and immunogenic vaccine and can safely be used for post-exposure prophylaxis.