The Brazilian government has ordered the temporary suspension of its national dengue vaccination pilot program following the confirmation of two deaths and 42 cases of severe adverse symptoms among individuals who recently received the immunization.
Health Minister Alexandre Padilha emphasized that there is currently no verified data proving that the vaccine, produced domestically by the Butantan Institute, is the direct cause of the complications or fatalities. Instead, the decision to halt the rollout was enacted strictly as a precautionary safety measure.
“There is no conclusive data establishing a causal relationship between the vaccine and these severe cases, but it serves as an important warning sign,” Padilha stated during a press conference in Brasília. He noted that the reported adverse events represent a very small percentage of the total population immunized, given that approximately 500,000 doses have been successfully administered across the selected pilot areas since January.
According to Eder Gatti Fernandes, the director of the National Immunization Program (PNI), the affected individuals initially developed mild symptoms resembling classic dengue fever before the conditions escalated into more severe medical scenarios, including persistent abdominal pain, intense vomiting, and hemorrhaging.
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The temporary suspension will remain in place while the Ministry of Health and the National Health Surveillance Agency (Anvisa) thoroughly analyze clinical data and conduct diagnostic tests to verify the drug’s long-term safety profile.
The suspended immunization initiative began earlier this year as a localized pilot project targeted at vaccinating individuals between the ages of 15 and 29. The specific municipalities selected for this initial phase include Maranguape in the northeastern state of Ceará, Nova Lima in Minas Gerais, and Botucatu in São Paulo.
Health officials clarified that this halt does not impact the availability of Brazil’s alternative dengue vaccine, which is manufactured separately by the Japanese pharmaceutical company Takeda (referred to in local procurement channels as Qdenga).
The emergency review comes on the heels of major public health challenges in South America. In 2024, Brazil experienced its worst dengue epidemic on record, resulting in an unprecedented 6.5 million probable infections and 6,321 confirmed deaths. While epidemiological figures improved significantly over the subsequent year—dropping to 1.6 million cases and 1,793 fatalities—controlling the mosquito-borne disease remains a critical priority for national sanitary authorities.
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Medical teams are advising anyone who received the Butantan vaccine within the last 21 days to closely monitor their health and seek immediate attention at a Basic Health Unit (UBS) if they experience a high fever, severe dizziness, or signs of abnormal bleeding.
