Analyses of pooled data from the two Phase 3 trials (CYD14 in Asia-Pacific and CYD15 in Latin America) showed
a reduction in dengue disease during the first 25 months of the study among children and adolescents 2-16
years of age who received CYD-TDV, consistent with previously published results from each trial. The pooled
data allowed for greater post-hoc analysis of age effects. Among individuals aged 9 years and older, efficacy
was substantially higher at 65.6% than in younger children. Children aged 9 and older who had evidence of
prior dengue virus infection (i.e., were seropositive) had an efficacy of 81.9%; seronegative individuals in this
age group had significant efficacy of 52.5%. Serotype-specific efficacy was also significant in the older age
group, ranging from 47.1% against serotype 2 to 83.2% against serotype 4. Among children younger than 9
years of age, efficacy was lower at 44.6% with 70.1% efficacy in seropositive and 14.4% in seronegative
children. Efficacy against severe dengue and hospitalization was 93.2% and 80.8%, respectively, in individuals
aged 9 years or older; and 44.5% and 56.1%, respectively, in children younger than 9 years