Role of the dengue vaccine TAK-003 in an outbreak response: Modeling the Sri Lanka experience.
Role of the dengue vaccine TAK-003 in an outbreak response: Modeling the Sri Lanka experience.
Blog Article
BackgroundOutbreaks of dengue can overburden hospital systems, drastically reducing capacity for other care.The 2017 dengue serotype 2 (DENV-2) outbreak in Sri Lanka coincided with vaccination in an ongoing phase 3 efficacy trial of a tetravalent dengue vaccine, TAK-003 (NCT02747927).Here, we present data on the efficacy of TAK-003 following two doses of the vaccine administered 3 months apart in participants aged 4-16 years in Sri Lanka.
In addition, we have used the 2017 outbreak dynamics to model the potential impact of TAK-003 on virologically confirmed dengue (VCD) cases and hospitalizations during an outbreak situation.Methodology/principal findingsModeling was performed using an age-structured, host-vector, spatial and stochastic transmission model, assuming 65% vaccine coverage and 30 days until initiation of vaccination.Efficacy of TAK-003 against VCD and hospitalized VCD cases was based on data against DENV-2 from the first year of the phase 3 trial.
Vaccine efficacy and safety findings in Sri Lanka Knife Rolls/Cases were in line with those of the overall trial population.The efficacy estimates in Sri Lanka up to Hood Scoops the first 12 months after the second dose of TAK-003 were 94.7% and 95.
7% against VCD and hospitalized VCD cases, respectively.Modeling of the trial data over an extended geographic area showed a substantial reduction in cases and a flattening of outbreak curves from TAK-003 use.The baseline vaccination scenario (initiation at 30 days, 65% target coverage, vaccine effective at 14 days, 70% hospitalization rate, VE of 95% for VCD and 97% for hospitalized VCD, and 47% for asymptomatic) resulted in a 69.
1% reduction in VCD cases and 72.7% reduction in VCD hospitalizations compared with no vaccination.An extreme high scenario (vaccination initiated at Day 15, 80% coverage rate, baseline VE) resulted in 80.
3% and 82.3% reduction in VCD and VCD hospitalizations, respectively.Vaccine performance, speed of vaccination campaign initiation, and vaccine coverage were key drivers in reducing VCD cases and hospitalizations.
Conclusions/significanceOverall, the study and modeling results indicate that TAK-003 has the potential of meaningful utility in dengue outbreaks in endemic areas.