In 2016, WHO1 recommended that the dengue vaccine CYD-TDV (Dengvaxia; Pasteur, Lyon, France), the first dengue vaccine, licensed for use in adults and children aged 9 years or older, be considered for use in highly endemic regions where at least 70% of 9-year-old children had previously been infected with dengue. The Philippines was the first country to introduce Dengvaxia on a large scale in selected highly endemic regions, targeting about 1 million children aged 9–10 years. In November, 2017, an excess risk of hospitalisation for dengue and severe dengue in vaccinees who had not had a previous dengue infection at the time of vaccination was reported,2 on the basis of retrospective analyses3 of data from the Dengvaxia phase 3 trials, using a novel non-structural protein 1 (NS1) based antibody assay. Following a reanalysis of these data,3 the Philippine Dengvaxia programme was suspended. However, by the time the programme had been suspended, more than 830 000 children had received at least one of the three recommended Dengvaxia doses. The news about the safety concerns in dengue-naive vaccinees led to major public outcry, with loss in vaccine confidence that extended to routine childhood vaccines.4
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32525-5/fulltext