Vaccines remain one of the decisive markers in our life expectancy
Butantan-DV is Brazil's first nationally-developed dengue vaccine, tested exclusively in Brazilian centers including UFMT's hospital and medical school. The five-year study tracked 1,300 volunteers in Mato Grosso, maintaining over 90% participation and demonstrating 74.4% efficacy in preventing dengue cases.
- Butantan-DV is the world's first single-dose dengue vaccine, developed entirely in Brazil
- Clinical trials at UFMT tracked 1,300 volunteers over five years with 90% retention
- Vaccine shows 74.4% efficacy in people aged 12-59 years
- Mato Grosso recorded 34,962 suspected dengue cases in 2025, with 21 confirmed deaths
Brazil's Butantan Institute has developed the world's first single-dose dengue vaccine, with clinical trials conducted at UFMT involving 1,300 volunteers over five years. The vaccine shows 74.4% efficacy and is expected to reach the public health system by December 2025.
For nearly a decade, researchers at the Federal University of Mato Grosso watched over thirteen hundred people. They drew blood, tracked fevers, monitored for symptoms—all to answer a single question: could a single injection protect against dengue? This week, that question found its answer. The Butantan Institute announced approval of Butantan-DV, the world's first single-dose dengue vaccine, and it is entirely Brazilian.
The clinical trials that made this possible unfolded across sixteen research centers in Brazil, but the work in Mato Grosso proved essential. Between 2016 and 2025, the Federal University's Hospital Júlio Müller and its medical school enrolled and monitored participants from Cuiabá and Várzea Grande. The vaccine showed 74.4 percent efficacy in people aged twelve to fifty-nine—meaning roughly three-quarters of vaccinated individuals were spared infection. That number carries weight in a state where dengue has circulated heavily for two decades.
Luciano Gomes, a forty-three-year-old professor and research coordinator at the university, recalls the hardest part was not the science but the recruitment. Brazil has never cultivated a strong culture of clinical trial participation, and finding thirteen hundred willing volunteers required sustained effort from his team. "The most difficult thing," he said, "is selecting the volunteer." Yet they met their target. The hospital provided the infrastructure, the logistical support, and the medical backup—all financed by Butantan. A team of up to thirty researchers maintained contact with both the vaccinated group and those who received placebo, managing to keep more than ninety percent of participants engaged through the full five-year follow-up.
The first three weeks marked the critical window for evaluation, but the real work was the years that followed. Gomes sees in this vaccine something beyond epidemiology. A single dose, he believes, removes a barrier that has lately plagued immunization campaigns across Brazil. "I hope we can break through some of the resistance people have developed toward vaccination," he said. "Vaccines remain one of the decisive markers in the evolution of our life expectancy."
Mato Grosso needs this protection. The state ranks fifth nationally in suspected dengue cases, with 34,962 infections recorded in 2025 alone. Twenty-one deaths have been confirmed, and fourteen more remain under investigation. The disease strikes hardest among people aged twenty to thirty-nine. Women account for fifty-five percent of suspected cases, and those who identify as mixed-race comprise sixty-three and a half percent of notifications. The vaccine is expected to reach the public health system in December, with mass vaccination campaigns planned for 2026. For a state that has endured two decades of dengue circulation, a single injection may finally offer a way forward.
Notable Quotes
The most difficult thing is selecting the volunteer. Graças ao esforço da equipe a gente conseguiu incluir 1.300 pessoas.— Luciano Gomes, research coordinator and UFMT professor
I hope we can break through some of the resistance people have developed toward vaccination. Vaccines remain one of the decisive markers in the evolution of our life expectancy.— Luciano Gomes
The Hearth Conversation Another angle on the story
Why did it take five years to test a vaccine that's given in a single dose?
The initial three weeks tell you whether the vaccine triggers an immune response, but dengue doesn't announce itself on a schedule. You need years of follow-up to see who actually gets infected and who doesn't. That's where the real efficacy number comes from—watching real people in real life.
Thirteen hundred volunteers is a lot. How did they convince people to stay in the study that long?
That was the hardest part. Brazil doesn't have a tradition of people volunteering for clinical research. The team had to build trust, show up consistently, make it easy for people to participate. Keeping ninety percent of them for five years meant the hospital became part of their lives, not just a place they visited once.
Seventy-four percent efficacy—is that good enough?
It's solid. It means roughly three out of four vaccinated people won't get dengue. In a state where the virus has been circulating for twenty years, that's a significant shift. And a single dose means more people will actually get vaccinated, which multiplies the benefit.
Why does a single dose matter so much?
Compliance. If you need two shots, some people forget the second one, some lose interest, some can't make it back. One shot removes that friction. In a country where vaccine hesitancy is already rising, that simplicity could be the difference between a campaign that works and one that doesn't.
Mato Grosso had thirty-five thousand cases this year. Will this vaccine change that number?
Not immediately. Mass vaccination starts in 2026, and it's only approved for people twelve to fifty-nine. But yes, over time, if uptake is strong, you should see the case numbers drop. The real test is whether people actually show up to get it.