From the FDA Drug Label
The efficacy of DENGVAXIA was evaluated in two randomized, observer-blind, placebo-controlled, multi-center studies. Study 1 (N=20,869) was conducted in individuals 9 through 16 years of age in four Latin American countries and Puerto Rico; and Study 2 (N=10,275) was conducted in individuals 2 through 14 years of age in five Asia-Pacific countries A subset of subjects in each study (10% in Study 1; 20% in Study 2) was evaluated for antibodies to dengue virus at the time of enrollment and at later time points. Both studies enrolled subjects irrespective of evidence of previous dengue infection Subjects were randomized 2:1 to receive either DENGVAXIA or saline placebo and were monitored for symptomatic virologically confirmed dengue (VCD) starting at Day 0. Per protocol vaccine efficacy was assessed beginning 28 days after the third vaccination for 12 months VCD was defined as an acute febrile illness (temperature ≥38°C on at least 2 consecutive days) virologically confirmed by dengue RT-PCR and/or dengue non-structural protein 1 (NS1) ELISA Antigen Test For each study, in pre-specified vaccine efficacy analyses including the full age range of subjects enrolled, the pre-specified criterion for demonstrating efficacy of DENGVAXIA against VCD due to any dengue virus serotype and irrespective of previous dengue virus infection, was met (lower bound of 95% CI for vaccine efficacy >25%) These studies were not designed to demonstrate efficacy of DENGVAXIA against individual dengue serotypes. Given the identification of the increased risk for severe dengue following vaccination with DENGVAXIA and subsequent infection with dengue virus in persons not previously infected with dengue virus [see Adverse Reactions (6. 1)], Table 4 presents analyses of vaccine efficacy against VCD due to any dengue virus serotype, limited to subjects who had baseline sera evaluated and who were dengue seropositive at baseline. These analyses include subjects 9 through 16 years of age from Study 1 and subjects 6 through 14 years of age from Study 2 Table 4: Efficacy of DENGVAXIA against Symptomatic VCD in Subjects Seropositive for Dengue at Baseline from 28 Days Post Dose 3 for a Period of 12 Months – Study 1 (Ages 9 through 16 Years) and Study 2 (Ages 6 through 14 Years) – mFASE* – Subjects Included in the Immunogenicity Subset DENGVAXIA group Cases (Subjects)Placebo group Cases (Subjects)VE % (95% CI)†
- mFASE (Modified Full Analysis Set): Set of the subjects who received 3 injections as per randomization including those with protocol deviations. † VE is calculated as 1- ratio of density incidence of dengue between DENGVAXIA and Placebo groups. Study 1(Subjects 9 through 16 years of age)7 (1034)17 (492)80.6 (50.7;93.2) Study 2(Subjects 6 through 14 years of age)6 (649)15 (337)79.5 (44.2;93.5)
The efficacy of DENGVAXIA in preventing dengue disease is as follows:
- In seropositive individuals (those who had previous dengue infection), the vaccine efficacy was:
- 80.6% (95% CI: 50.7;93.2) in Study 1 (subjects 9 through 16 years of age)
- 79.5% (95% CI: 44.2;93.5) in Study 2 (subjects 6 through 14 years of age)
- The studies were not designed to demonstrate efficacy of DENGVAXIA against individual dengue serotypes.
- The vaccine efficacy was assessed beginning 28 days after the third vaccination for 12 months.
- The pre-specified criterion for demonstrating efficacy of DENGVAXIA against VCD due to any dengue virus serotype and irrespective of previous dengue virus infection, was met (lower bound of 95% CI for vaccine efficacy >25%) 1
From the Research
Dengue fever vaccines, such as TAK-003, provide approximately 80% efficacy against symptomatic dengue and about 90% protection against hospitalization in the first year after vaccination, with protection gradually decreasing over time, as shown in the most recent and highest quality study 2. The most recent and highest quality study, published in 2019, demonstrated the efficacy of the TAK-003 vaccine in preventing dengue infection 2. This study found that the vaccine had an overall efficacy of 80.9% in preventing virologically confirmed dengue caused by any dengue virus serotype. Some key points to consider when evaluating the efficacy of dengue vaccines include:
- The level of protection offered by the vaccine, with TAK-003 providing approximately 80% efficacy against symptomatic dengue 2
- The duration of protection, with protection gradually decreasing over time 2
- The risk of severe disease in dengue-naïve individuals, which is increased with the use of some vaccines, such as Dengvaxia 3
- The importance of personal protective measures against mosquito bites, as no dengue vaccine provides complete protection 4 It is also important to note that the efficacy of dengue vaccines can vary depending on the serotype of the virus and the individual's previous immune status, as demonstrated in studies such as 5. Overall, the use of dengue vaccines, such as TAK-003, can provide significant protection against dengue infection, but it is essential to consider the individual's risk factors and previous immune status when making vaccination decisions.