The Brazilian government has temporarily suspended the rollout of the world’s first single dose dengue vaccine.
There have been reports of two deaths and 42 cases of serious adverse reactions after inoculation.
The vaccine, developed by the Butantan Institute, has been administered to approximately 500,000 individuals.
“The Ministry of Health reported 42 cases, or 0.008 percent of the 500,000 doses given through May 30, though officials are unsure if the vaccine caused the problems. This pause serves as a precautionary measure to respect life and science, allowing deeper probes by the Ministry of Health, Anvisa, and the Butantan Institute, especially into the deaths where no causal link is yet established. The step aims to ensure safety for future vaccination stages, with plans to resume soon if confirmed safe. The vaccine, developed by the Butantan Institute using U.S. technology, is a live attenuated version covering four dengue virus serotypes and was approved in 2025,” The Epoch Times wrote.
“Brazil launched the campaign in early 2026, targeting health care workers and people aged 15 to 49 in three cities in northern Tocantins state. Dengue has hit hard, with 6.5 million probable cases in 2024—four times the prior year—and 1.6 million by mid-November 2025, affecting over 20 million Brazilians since the 2000s. Testing showed the vaccine protects against dengue and severe cases, and fewer infections have been recorded since rollout compared to the same period in 2024,” it continued.
Brazil has suspended its dengue vaccination campaign after two deaths, halting the world's first single-dose vaccine to investigate the cases and related warning signs.
The Ministry of Health reported 42 cases, or 0.008 percent of the 500,000 doses given through May 30, though… pic.twitter.com/DuLxYAvj5H
— The Epoch Times (@EpochTimes) June 16, 2026
Reuters explained further:
Authorities clarified that there is no conclusive evidence directly linking the deaths to the vaccine, but decided to halt vaccinations as a precaution while investigations proceed.
The measure affects the world’s first single-dose dengue vaccine, considered one of the most important health projects in Latin America in recent years. The vaccine, known as Butantan-DV, was approved by Brazilian regulatory authorities in late 2015 and began mass vaccination in January of this year, primarily among healthcare workers and residents of regions with a high incidence of the disease.
According to the Brazilian Ministry of Health, the serious cases identified include the deaths of a 48-year-old woman and a 58-year-old man, as well as a patient who required intensive care and was later discharged. Health authorities indicated that the 42 serious adverse events represent a very small proportion of the total number of vaccinated individuals.
Health Minister Alexandre Padilha stated that the suspension aims to allow for a thorough evaluation of the reported cases and emphasized that the decision does not imply any questioning of the vaccine’s efficacy. Clinical studies conducted prior to its approval showed an efficacy of over 74% against symptomatic dengue and complete protection against hospitalizations during the analyzed period.
The Butantan Institute licensed the technology for the vaccine from the U.S. National Institutes of Health in 2009, the BMJ noted.
Brazil has suspended its rollout of the world’s first single dose dengue vaccine, after two healthcare workers died after receiving the vaccine and 42 unexpected adverse events were reportedhttps://t.co/ovtPqXAxXG
— The BMJ (@bmj_latest) June 15, 2026
More from the BMJ:
A five year phase 3 trial found that a single dose was 65% effective against symptomatic dengue and 80.5% effective against severe dengue. The Butantan Institute says that more than a million doses have already been produced and that the initial rollout was intended to help determine how best to expand vaccination across Brazil.
The Ministry of Health said that the suspension did not invalidate the vaccine’s efficacy or the protection already offered to the people immunised. It said that the suspension showed that Brazil’s vaccine safety monitoring system was functioning well by rapidly detecting the possible safety concerns.
Padilha added that the Ministry of Health had “total confidence in Butantan’s institutional capacity.”
Dengue is a mosquitoborne viral disease that typically causes high fever, headache, and muscle and joint pain. In severe cases it can cause internal bleeding, organ failure, and death.
ADVERTISEMENTWorldwide, dengue cases are on the rise, driven partly by climate change and growing urbanisation. Global dengue transmission reached a historic high in 2024, with the World Health Organization reporting more than 14.6 million cases and more than 12 000 dengue related deaths worldwide. The Americas accounted for more than 13 million of the cases, with Brazil driving the regional surge.
