Detection of dengue cases by serological testing in a dengue vaccine efficacy trial: Utility for efficacy evaluation and impact of future vaccine introduction.

•Virologically-confirmed dengue cases serology profile in vaccine trial is described.•We evaluated applicability of the WHO case definition for dengue in vaccine trials.•False positives are common with dengue diagnosis based on IgM/IgG after vaccination.•Lack of specificity and bias after vaccination limits IgM/IgG use for surveillance.•Dengue diagnoses based on IgM/IgG need strengthening following vaccine introduction.