Study participants and cohorts
YFV, TBEV
The study was initially designed to include a total of 140 healthy volunteers. Forty study participants were to receive both TBEV and YFV vaccines (cohort A). Twenty of these participants were to receive the vaccines in different upper arms (sub-cohort A1) and the other 20 in the same upper arm (sub-cohort A2). The next 40 study participants were to receive both JEV and YFV vaccines (cohort B). Similarly, 20 of these participants were to receive the vaccines in different upper arms (sub-cohort B1) and the other 20 in the same upper arm (sub-cohort B2). The remaining three cohorts of 20 study participants per cohort, were aimed to serve as study controls and were to receive either, the TBEV vaccine (cohort C), JEV vaccine (cohort D), or YFV vaccine (cohort E). Information on sample size calculations are outlined in the Study Protocol (available upon request). With respect to sample size, one emphasis of the present study was to study immunological reactivity over a longer period with multiple frequent samplings of peripheral blood. Study groups were recruited one at a time, and initiated in the order (A1, A2, C, B1, B2, D, and E).Upon initiation of the clinical trial, a total of 161 healthy volunteers were screened for enrollment (