Background
Butantan-Dengue Vaccine (Butantan-DV) is an investigational, live, attenuated, single-dose, quadrivalent vaccine against dengue disease, but data on its overall efficacy are needed.
Methods
In an ongoing double-blind phase 3 trial in Brazil, we randomly assigned participants to receive Butantan-DV or placebo, with stratification by age (2 to 6 years, 7 to 17 years, and 18 to 59 years); A 5-year follow-up is planned.
The objectives of the trial were to evaluate the overall efficacy of the vaccine against symptomatic and virologically confirmed dengue of any serotype occurring more than 28 days after vaccination (the primary efficacy endpoint), regardless of baseline serostatus. and describe safety through day 21 (the primary safety endpoint).
Here, vaccine efficacy was assessed based on 2 years of follow-up for each participant, and safety based on solicited vaccine-related adverse events reported up to day 21 post-injection.
Key secondary objectives were to evaluate vaccine efficacy among participants based on dengue serostatus at baseline and dengue viral serotype; Efficacy was also evaluated according to age.
Results
Over a 3-year enrollment period, 16,235 participants received Butantan-DV (10,259 participants) or placebo (5,976 participants).
Overall vaccine efficacy at 2 years was 79.6% (95% confidence interval [CI], 70.0 to 86.3), 73.6% (95% CI, 57.6 to 83.7) among participants without evidence of prior exposure to dengue and 89.2% (95% CI, 57.6 to 83.7). CI, 77.6 to 95.6) among those with a history of exposure .
Vaccine efficacy was 80.1% (95% CI: 66.0 to 88.4) among participants aged 2 to 6 years, 77.8% (95% CI: 55.6 to 89.6) among those aged 7 to 17 years and 90.0% (95% CI: 55.6 to 89.6, 68.2 to 97.5) among those aged 18 to 59 years.
Efficacy against DENV-1 was 89.5% (95% CI, 78.7 to 95.0) and against DENV-2 was 69.6% (95% CI, 50.8 to 81.0). 5). DENV-3 and DENV-4 were not detected during the follow-up period.
Solicited adverse events related to systemic vaccine or placebo within 21 days of injection were more common with Butantan-DV than with placebo (58.3% of participants, vs. 45.6%).
Conclusions A single dose of Butantan-DV prevented symptomatic DENV-1 and DENV-2, regardless of dengue serostatus at baseline, over 2 years of follow-up. |
(Funded by the Butantan Institute and others; DEN-03-IB ClinicalTrials.gov number, NCT02406729. opens in a new tab and WHO ICTRP number, U1111-1168-8679. opens in a new tab.)
