Butantan dengue vaccine: government has no deadline for investigation

The Ministry of Health stated this Monday (8) that there is still no defined deadline for the conclusion of the investigation involving the dengue vaccine developed by the Butantan Institute, which had its application temporarily suspended by the federal government.

During a press conference, representatives from the department stated that the ministry has demanded speedy analysis, but emphasized that the process will follow the safety and pharmacovigilance protocols adopted by the SUS (Unified Health System).

When asked how many cities received the vaccine during the campaign, the ministry stated that the data would still be collected and could be released later. The number was not given during the press conference.

According to data presented by the National Immunization Program (PNI), 501,044 doses of the vaccine were administered between January and May 30 of this year. Of this total, 417,432 were allocated to primary health care professionals across the country and 83,612 were applied in expanded vaccination strategies carried out in Botucatu (SP), Nova Lima (MG), Maranguape (CE) and the Araguaína region (TO).

The decision does not affect the dengue vaccine currently offered by the Unified Health System (SUS) for children and adolescents aged 10 to 14 years. The suspension exclusively involves the immunizer developed by the Butantan Institute.

42 cases are being investigated
According to the Ministry of Health, the pharmacovigilance system identified 3,703 notifications of people who presented symptoms similar to dengue after vaccination, equivalent to 0.7% of those vaccinated.

Among these records, 42 cases showed warning signs, such as abdominal pain, persistent vomiting and bleeding. According to the ministry, these events represent 0.008% of the total number of people vaccinated and are considered rare, although unexpected, as they had not been identified in clinical studies nor predicted in the leaflet.

Three serious cases
Among the 42 serious adverse events, three cases caught the attention of health authorities and began to be investigated in depth.

The first involves a 39-year-old woman who developed fever, muscle pain and nausea six days after receiving the vaccine. It evolved into a condition compatible with severe dengue, with shock and the need for admission to an intensive care unit (ICU). The patient was discharged.

The second case was recorded in a 48-year-old woman who developed symptoms of severe dengue associated with neurological impairment, described as meningoencephalitis, 19 days after vaccination. She died.

The third case involves a 58-year-old man who developed a fever five days after receiving the vaccine and quickly progressed to severe dengue fever with refractory shock. The patient also died.

Where they occurred
According to the Ministry of Health, the three serious cases occurred among primary health care professionals, a group that received most of the doses distributed by the federal government.

The Minister of Health, Alexandre Padilha, stated that none of the serious cases or deaths were registered in Botucatu, Nova Lima, Maranguape or the Araguaína region, locations where vaccination was expanded to the entire population aged 15 to 59.

Part of the 42 serious adverse reactions were recorded in these regions, but the three most serious cases occurred among healthcare professionals vaccinated in other parts of the country.

Did the vaccine cause the cases?
The Ministry of Health states that it is not yet possible to conclude that the events were caused by the vaccine. According to the ministry, the temporal proximity between immunization and the appearance of symptoms does not prove a cause and effect relationship.

Investigations analyze clinical history, pre-existing diseases, individual risk factors, possible alternative causes, quality deviations and possible immunization errors. The cases are being evaluated by the Interinstitutional Committee for Pharmacovigilance of Vaccines and Other Immunobiologicals (Cifavi) and the Technical Advisory Chamber on Immunization (Ctai).

Understand why vaccination was suspended
According to the Ministry of Health, the suspension is preventive in nature and seeks to allow additional studies to assess the safety of the vaccine in different population groups and epidemiological scenarios.

Starting this Tuesday (9), states and municipalities will be instructed to temporarily interrupt the application of the vaccine to both primary care professionals and cities that participated in the expanded vaccination strategy. The doses will remain stored in the cold chain while investigations continue.

Anyone who has already taken the vaccine is still protected?
The Ministry of Health states that the suspension does not invalidate the effectiveness of the vaccine. According to the ministry, anyone who has already received the vaccine remains protected against the four dengue serotypes.

The advice is that people vaccinated in the last 21 days should be alert to symptoms such as fever, intense and continuous abdominal pain, persistent vomiting, dizziness, bleeding, intense drowsiness, irritability, signs of dehydration and worsening of the general condition. If symptoms worsen, it is recommended to seek medical attention immediately.

See Butantan's statement
"The Butantan Institute informs that, following guidance from the Ministry of Health and Anvisa, vaccination against dengue will be, in a preventive manner, temporarily interrupted to reevaluate the vaccination strategy.

At the moment, healthcare professionals were being vaccinated. The guidance occurs due to some cases of adverse reactions detected, three of them with signs of severity, in a universe of approximately 500 thousand vaccinated people, which may or may not be related to vaccination. The measure aims to ensure the safety of the population in the next stages of vaccination.

The Butantan Institute maintains its commitment and absolute rigor to science and the health of the population and will continue working to support the Ministry of Health and Anvisa, providing all available information about the vaccine, carrying out new studies and monitoring the pharmacovigilance work of those vaccinated. It is worth noting that the vaccine had an overall efficacy of 79.6% and 89% against severe dengue in a study published in an international scientific journal. In the three municipalities where there was mass vaccination of the population - Botucatu (SP), Maranguape (CE) and Nova Lima (MG), pharmacovigilance monitoring was positive, with no important cases of adverse reactions in the population.

The Butantan Institute, as already demonstrated in recent cases, will continue working with the utmost rigor to deepen information on the use of the vaccine so that, if its safety is confirmed, vaccination can be resumed soon, with complete peace of mind for the population served by the SUS. The Butantan Institute reaffirms its commitment to delivering safe and effective products to address Brazilian public health problems through the SUS."

Source: CNN