Reply to Aguiar and Stollenwerk

To the Editor—Aguiar and Stollenwerk [1] analyzed the safety data provided in Martínez-Vega et al [2] for 2 phase 3 clinical trials of Dengvaxia during up to 6 years of follow-up. The authors reported negative vaccine efficacy (VE) against hospitalization, –76% among baseline seronegative individuals 2–8 years old and –40% among 2–16 years old and expressed their concerns, although neither estimate is statistically significant. Martínez-Vega et al presented similar results but challenged the concept of vaccine-induced antibody-dependent enhancement among seronegative young children [2]. Despite the safety concerns, Dengvaxia remains important in the current portfolio for controlling dengue [3]. The ongoing debate on the utility of Dengvaxia justifies our focus on a thorough quantification of the impact of preexposure and age on VE against general dengue disease during the 25-month active phase [4]. A deep understanding of major determinants of the VE against general clinical outcomes would greatly benefit the assessment of the overall public health impact of Dengvaxia in the long run, for example, using the approach of mathematical modeling [3, 5].