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 ).