Incidence of clinical dengue over time after vaccine introduction. Figure showing changes in the incidence of clinical dengue during the years following vaccine introduction (time=0, dashed line). Left: Relative yearly incidence of clinical dengue as compared to the average yearly incidence before vaccine introduction. Right: Reductions in the cumulative incidence of clinical dengue at different times after vaccine introduction, relative to the cumulative incidence had the vaccine not been introduced. We present results for three different scenarios. A) Risk of developing clinical disease after DENV-2 infection is 1.5 times greater than after infection by any other serotype. B)Transmission intensity of DENV-2 is 1.5 times higher than the transmission intensity of any other serotype. C) Secondary infection by DENV-2 results in infectiousness enhancement by a factor of 1.5. In all cases, the vaccine efficacy against dengue 1, 3, and 4 was assumed to be 0.8.