Efficacy of rabies vaccine with differing antigen payloads on pre and simulated post-exposure prophylaxis in cattle

Rabies is a fatal disease of humans and animals. Over the years various vaccines and vaccination procedures such as pre-and post-exposure prophylaxis (PrEP and PEP) have been used to control the losses incurred due to rabies. Unlike in humans, no firm PrEP and PEP guidelines are available for control of rabies in animals. In this study, healthy cattle calves were vaccinated with either single (PrEP regime) or five doses (simulated PEP regime) of rabies vaccine with a potency of 1.2 IU/dose or 2.7 IU/dose. Vaccine was administered on Day 0, 3, 7, 14 and 28 as per ‘Essen’ regimen. The serum was collected from all the vaccinated cattle on 0, 7, 14, 28 and 60 days post inoculation (dpi) and virus neutralisation antibody (VNA) levels were determined by fluorescent antibody virus neutralisation test (FAVN). The results reveal that vaccination with single dose of 2.7 IU/dose of rabies vaccine induced higher VNA in serum compared with 1.2 IU/dose vaccine. Comparison of serum antibody levels between animals vaccinated with single dose of high antigen payload (2.7 IU/dose) and multiple vaccination with 1.2 IU/dose vaccine showed significantly higher antibody levels in the former at 14, 28 and 60 dpi intervals. From this study, it is concluded that the protective levels of immunity in cattle can be achieved with high antigen payload vaccines with either two or three doses, respectively, in PrEP and simulated PEP programs.