New Dengue Vaccine Suspended in Brazil After Severe Adverse Event Reports

Brazil’s Ministry of Health and the National Health Surveillance Agency (ANVISA) suspended a mass vaccination campaign using a new dengue vaccine developed by a Brazilian biomedical research center after severe adverse events, including deaths, were associated with certain batches of the vaccine. Authorities have opened an investigation into the incidents while continuing to assess the vaccine’s safety profile.

The vaccine known as Butantan-DV, developed by the Butantan Institute in São Paulo, Brazil, is the world’s first single-dose dengue vaccine.¹ It is a single-dose, live-attenuated, tetravalent vaccine against all four strains of the mosquito-borne dengue virus.² It uses a genetically modified dengue virus with limited replication capacity and is used in both seropositive individuals with dengue antibodies and seronegative individuals without dengue antibodies.³

Dengue is one of the country’s most significant mosquito-borne viral diseases. Symptoms include high fever; joint, bone and muscle pain; sudden high blood pressure; severe headaches; and hemorrhages (bleeding) that can cause death.⁴ Public health authorities recommend the elimination of mosquito breeding sites as the primary preventive measure.⁵

Brazil Approved the New One-Dose Dengue Vaccine in 2015

 The vaccine received approval from Brazilian regulators in late 2015 and was rolled out for mass vaccination in January of this year, with priority given to healthcare professionals and people living in areas heavily affected by dengue. The public health campaign was celebrated as milestone for Latin America, as a single-dose vaccine significantly speeds up and simplifies mass vaccination efforts compared to traditional multi-dose options.⁶

Qdenga (TAK-003), another dengue vaccine produced by Takeda Pharmaceuticals, still remains available in Brazil. However, limited manufacturing capacity and its two-dose schedule have constrained supply, restricting widespread vaccination efforts in both endemic and non-endemic regions.⁷

Health Authorities Investigate Suspected Dengue Vaccine Deaths

Between January and May 2026, health care workers administered the vaccine to 501,044 individuals. Among these recipients, 3,703 people reported symptoms similar to dengue fever itself. The Ministry of Health also tracked 42 individuals who experienced very severe adverse reactions.⁸ These patients experienced intense and persistent abdominal pain and vomiting, as well as bleeding (hemorrhages).⁹

Public health records show that these serious adverse reactions resulted in the deaths of a 48-year-old woman and a 58-year-old man. A third patient, a 38-year-old woman, required intensive care treatment following vaccination but has since recovered.¹⁰

The government initiated the temporary suspension of the vaccine campaign to allow surveillance teams to evaluate the medical histories and risk factors associated with these severe adverse event cases. Health Minister Alexandre Padilha emphasized that the government ordered the halt to the mass vaccination campaign strictly as a preventative warning signal to protect the public. During a press conference, Padilha stated that authorities currently lack conclusive data to establish a definitive cause-and-effect link between the single-dose dengue vaccine and these deaths.

Brazilian government health officials said that the 42 recorded severe adverse events represent a very small statistical proportion of the half-million citizens who have been vaccinated so far.¹¹

If you would like to receive an e-mail notice of the most recent articles published in The Vaccine Reaction each week, click here.