2.7. Study Outcomes
For the 18–60 age cohort, the primary outcomes for safety assessment were the frequency and severity of AEs within the observation period (72 h, 7 days after each vaccination and 28 days after the 2nd vaccination). The primary immunogenicity endpoints were the geometric mean nAB titer (GMT) and seroconversion rate (defined as a 4-fold or higher increase in GMT of specific antibodies in the NT) 28 days after the 2nd vaccination. Secondary endpoints included seroconversion rates at Days 7 and 14 and Months 2, 3, 4, 5 and 6 after the 2nd vaccination.For the 60+ age cohort, the primary outcomes of immunogenicity assessment were the proportion of study participants with an increase in GMT of specific antibodies in the NT and seroconversion rate (defined as 4-fold or higher increase in GMT of specific antibodies in the NT) on Day 21 after the 3rd vaccination in comparison with the data obtained in healthy volunteers in the 18–60 age cohort. The primary outcomes of safety assessment were the frequency, type and severity of AEs and their relation to vaccination in comparison with the data obtained in healthy volunteers in the 18–60 age cohort.