Safety and Potency Test for PV and ERA Based Cell Culture Anti-Rabies Vaccines Produced in Ethiopia

Abstract

This research was aimed to evaluate safety and potency of PV and ERA based cell culture anti-rabies vaccines. Two rabies vaccinal strains (PV and ERA) used to produce virus suspension propagated on Vero and BHK-21 cell lines. Potency and safety of the vaccine studied after inactivation with formalin. Safety test performed to access residual virulent left during inactivation or to detect any bacteriological contaminant present in the crude vaccine, and no residual virus or bacterial contaminant was detected. Potency test determines the degree of protection conferred by the vaccine in immunized mice challenged with challenge virus standard. This test was performed using National Institutes of Health (NIH) potency test. Mice were immunized on day 0 and 7 with five different concentrations of test vaccine and four different concentrations of control vaccine, 16 mice in each dilution. The control vaccine used was VeroRab vaccine which was produced by Sanofi Pasteur. Standard CVS strain obtained from CDC Atlanta was used for challenging. Mice were challenged on day 14th with challenge virus strain (CVS-11) of 25 MLD50/0.03ml intra-cerebrally. The mice were observed for 14 days and death recorded for each dilution separately. Potency result calculated using NIH test and 8.32 IU/ml for ERA and 3.56 IU/ml for PV results were obtained. Based on WHO recommendation, these vaccines have high potency and upon dilution can be used for animal immunization.