Immunogenicity and safety of Abhay M and M-vac vaccines in healthy infants: a phase III multicentric randomized single blind trial.

ABSTRACT

OBJECTIVE: To study immunogenicity and safety of Abhay M and M-Vac vaccines in prevention of measles in healthy infants. METHODS: In a randomized, single blind, comparative, multi-centric phase III trial, a total of 600 healthy infants between 9 - 15 months of age were recruited in the study from seven participating sites during five months. The block randomization design was used for randomizing the subjects into 2 vaccine groups (Investigational Vaccine - Abhay M and Control Vaccine - M-Vac) in the ratio 21. At base line (visit 1) a venous blood sample 1.5 ml was collected and subjects were then administered a single dose 0.5 ml of measles vaccine (Abhay M or M-Vac vaccine) subcutaneously according to randomization. Following administration of vaccine, subjects were observed closely for 30 - 60 minutes at the study hospitals for local reactions and systemic events. At visit 2 (follow up visit) another venous blood sample 1.5 ml was collected and the paired sera (both pre and post vaccination serum) were tested concurrently. Safety and immunogenicity were assessed through follow-up of adverse events and anti measles antibody response respectively. RESULTS: Overall 95.7 % seroconversion was achieved in both the groups, 96% in Abhay M vaccine group and 95.1%. in M-Vac vaccine group. There were no statistically significant differences in the observed seroconversion rates. In Abhay M vaccine group, the pre vaccination geometric mean titers (GMT) significantly increased from 35.5 mIU/ml to 486.9 mIU/ml after vaccination. The observed significant increase of GMT in M-Vac vaccine group was from 33.3 mIU/ml to 375.8 mIU/ml. Overall 459 (82.5%) out of 556 subjects were seroprotected after vaccination i.e. > or equal to [corrected] 200 mIU/ml (Protective levels). Of the 459 seroprotected, 315 (84.9%) subjects were in Abhay M vaccine group and 144 (77.8%) subjects were in M-Vac vaccine group. The frequencies of the reported local and general symptoms were similar between the Abhay M vaccine group and M-Vac vaccine group. CONCLUSION: Human Biologicals Institute's Abhay M vaccine is equally immunogenic and as safe as M-Vac vaccine when administered to healthy infants in single dose schedule.