Safety and efficacy of oral rabies vaccines

Live oral rabies vaccines have been used for many years in Europe and the USA to control wildlife rabies. These vaccines are not considered safe for use in stray and ownerless dogs in India. In India the close association between humans and dogs increases the likelihood of direct exposure of humans to vaccine baits during oral vaccination programs.

Development of the ORA-DP/DPC strains

1. ORA-D vaccine virus
   In the original SAD strain the Arginine residue of Glycoprotein G at position 333 is replaced with Aspartic acid. ORA-D is non-pathogenic for adult mice given intracerebrally (IC), but remains pathogenic when given IC in baby mice.
   
2. ORA-DP vaccine virus
   The deletion several amino acids results in the removal of a nerve cell transporter. This affects the transport of the virus along nerves. The ORA-DP is safe in newborn suckling mice after intramuscular inoculation.
   
3. ORA-DPC vaccine virus
   ORA-DPC strain was developed to improve the immunogenicity of the above two strains. An additional glycoprotein G is inserted. This strain induces higher neutralizing antibody titres even in immuno-suppressed dogs. At the same time the additional glycoprotein G contributes towards improved safety.

The ORA-DPC vaccine strain is a safe effective candidate for the mass oral immunization of dogs.

For information on safety and efficacy laboratory trials see Trials.