Brazil suspends the new Dengue vaccine, stop after two suspected deaths and 42 adverse events

The Minister of Health: “Precautionary action, these are rare events”

It was the Minister of Health, Alexandre Padilha, who explained that the temporary suspension of the anti-Dengue vaccination strategy is “a precautionary action” to allow the Ministry of Health, the national health surveillance agency Anvisa and the Butantan Institute, which developed the vaccine, to investigate cases, “in particular deaths, for which there is not yet sufficient information to establish a causal link with the vaccine”.

Researchers will study the patients’ medical history, pre-existing conditions and individual risk factors, as well as alternative causes, possible quality issues and immunization errors, in order to identify possible links between their conditions and the Butantan-DV vaccine they received. The identification of these episodes occurred through pharmacovigilance, as part of a standard monitoring procedure that is adopted every time a new product of this type is introduced into the SUS healthcare system (Sistema Único de Saúde). These are rare eventsthe ministry specified in a note, which represent 0.008% of a total of over 500,000 doses administered up to May 30, and there is not yet a conclusive result on the correlation with the vaccine. The anti-Dengue vaccination strategy with the Butantan Institute vaccine was aimed at primary healthcare workers and, more generally, at the 15-49 age group in three cities – Botucatu, Maranguape and Nova Lima – and in the Araguaína region, in the state of Tocantins. The campaign started in January this year.

What should those who have already received the first dose do?

Those who have already received the vaccine have been advised to monitor your health for 21 days after vaccination. “It is important to underline that this measure does not invalidate the effectiveness of the vaccine nor alter the evidence of protection observed so far. Those who have already been immunized remain protected and epidemiological surveillance continues to monitor the vaccinated population”, the ministry note specifies. Clinical trials have proven for this vaccine an overall effectiveness of 65% and 80.5% for severe cases. After 21 days, no active components of the vaccine are detectable in the body.

The fight against Dengue continues – it was assured by the Brazilian health authorities in the note – with all the other control strategies implemented to reduce the circulation of the virus, prevent serious cases, reduce hospital admissions and avoid deaths. At the end of May this year, the country had recorded a 94% drop in the number of cases compared to the same period in 2024. Probable cases were in fact 365 thousand, compared to the 5.8 million recorded in the same period of 2024. As for deaths, the reduction was 97%, with 178 deaths recorded in 2026 and over 6,300 in 2024.