No abstract

Seven brands of veterinary rabies vaccines are commercially available in Sri Lanka, but there is no established procedure to test the potency of the vaccines at the local level, especially prior to their release. The aim of this study was to test the potency of these vaccines using a mouse challenge test in collaboration with the EU/WOAH/WHO Reference Laboratory for Rabies, ANSES-Nancy, France. Based on the European Pharmacopoeia, the inactivated rabies vaccines complied with the mouse potency test if the estimated potency is ≥1.0 IU in the smallest prescribed dose. Among the eight tested vaccines, four single-dose preparations (Rabisin™, Raksharab™, Nobivac™ RL, and Nobivac™ Rabies) were compliant, with potencies of 12 IU/dose, 7.2 IU/dose, 4.4 IU/dose, and 3.4 IU/dose, respectively. Three of the single-dose preparations (Canvac™ R, Defensor™ 3, and Rabies killed vaccine) were not compliant, with potency values <1.0 IU/dose. One multidose preparation (Raksharab™ multidose) had a potency of 1.3 IU/dose, even though the test was not validated. Based on these results, it appears that some rabies vaccine batches that are currently available in the local market do not comply with the mouse potency test. Testing the vaccines’ potency before registration and release to the market appears to be an important step to allow good immunization to animals during pre-exposure vaccination programs.

No abstract

Improved vaccine efficacy has a major impact on future rabies prevention and control. In this systematic review, a comparative assessment of different nucleic acid-based antirabies vaccination tools developed using different methods, in different countries, was undertaken. The comprehensive search was done in three databases. Articles were carefully selected based on predetermined inclusion/exclusion criteria and eight articles were included in this systematic review. Studies have demonstrated dose-dependent immune response following intramuscular vaccination and improved immune response following intranasal vaccination and gene-gun delivery method. Nucleic acid-based antirabies vaccines have shown higher immune response and protective levels in Bagg's albino (BALB/c) mouse models than cell culture-derived vaccines. It has been demonstrated that the route/method of administration and the vaccine formulation could be improved in various ways to enhance immune response following vaccination. These new vaccine tools and their implementation in pre- and postexposure prophylaxis could be further evaluated and to be adopted by rabies endemic countries.