Table 1: Results of Quality assessment for the four studies. |
Criteria |
Dayan, et al |
HSS, et al |
Lanata, et al |
Sabchare on, et al |
Villar, et al |
Leo, et al |
13. Were outcomes reported or subgroups analyzed prespecified( i. e., identified |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
before analyses were conducted)? |
|
|
|
|
|
|
14. Were all randomized participants analyzed in the group to which they were originally assigned, i. e., did |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
they use an intention-to-treat analysis? |
|
|
|
|
|
|
Score |
13 / 14 |
13 / 14 |
13 / 14 |
12 / 14 |
13 / 14 |
12 / 14 |
3.3. Study Designs and Characteristics
Table 2 provides the summary of the study design of all of the included studies. All of the studies followed a similar study design, and hence can be compared reliably. All studies were double-blinded( except for Leo, et al. 25) and adequately randomized the patients. In all studies, only healthy patients were selected.
There are some differences in the control group of the studies, as some use 0.9 % NaCl and others use other vaccines. However, we consider that this does not significantly affect the results as none of the control vaccines contain antigens for Dengue Virus. The study conducted by Leo, et al. 25 separated the data for different age groups, hence the data will be presented separately in Tables and charts.
3.4.1. Study Outcome: Efficacy of Intervention
The efficacy of CYD-TDV was primarily measured by analyzing the immunogenicity of the interventions, indicated by the geometric mean titers( GMT) of neutralizing antibodies( antibody titer) against each of the four antigens( DENV-1, DENV-2, DENV-3, DENV-4). The GMT represents the average antibody titer in a population of people.
Plaque reduction neutralization test( PRNT) was used to quantify the titer of antibodies in all trials. The data is represented on Figures 2-5, and also in Tables in the appendix.
The data is extracted for GMTs of antibodies against each antigen at baseline, after dose 2, and after dose 3 of both test and control groups in all 6 trials( except for the study by Leo, et al., 25 which only presented data for immunogenicity at baseline and post-dose 3).