Safety of Dengue Vaccine?
Aravinda de Silva
Abstract
To the Editor—I write in response to the recent publication from Takeda Pharmaceuticals about the safety of their dengue vaccine (Patel et al, Clinical Safety Experience of TAK-003 for Dengue Fever: A New Tetravalent Live Attenuated Vaccine Candidate) [1]. The authors conclude that “no important safety risks were identified, and TAK-003 was well tolerated irrespective of age, gender, or baseline dengue serostatus in recipients aged 4–60 years.” This conclusion does not accurately reflect recently published data for baseline seronegative children who received the vaccine [2]. In baseline seronegative children, Rivera et al [2] reported modest efficacy for serotype 1 (43.5%), high efficacy for serotype 2 (92%), and no efficacy for serotypes 3 (−23%) and 4 (−105%) over the first 36 months of the trial. By year 3 (months 24–36), the vaccine was only efficacious against serotype 2 (85%). Of special concern was a trend of more severe hospitalized dengue virus serotype 3 (DENV3) cases in the vaccine arm compared to the placebo arm (efficacy −183%) in baseline seronegative children. Although the investigators attribute this signal to high rates of dengue hospital admissions in Sri Lanka, this is not a satisfactory explanation.