Deaths in Brazil raise concerns about India’s dengue vaccine, DengiAll

15 JUNE 2026

The recent deaths of two people in Brazil during its dengue vaccination campaign, leading to the shot’s suspension on June 8, 2026 is a crucial wake-up call for India.
Of 42 vaccine recipients who displayed serious side-effects, two people died and one had to receive intensive care.
These side-effects included severe abdominal pain, persistent vomiting, and bleeding, none of which the phase 3 clinical trials revealed.
Brazilian authorities have stressed that the 42 cases of severe adverse events out of half-a-million vaccinated represent only 0.008%.
The dengue vaccine in Brazil, Butantan-DV, is pretty similar, if not identical, to India’s upcoming dengue vaccine, DengiAll.
Both vaccines were several years in the making.
Both have live but weakened (attenuated) versions of the dengue viruses (DENVs).
And both vaccines are said to be tetravalent because each vaccine is a physical mixture of four live, weakened DENV serotypes: DENV-1, -2, -3 and -4.
Another tetravalent dengue vaccine, Qdenga, marketed by Japan-based Takeda has its India approval awaited.

DENV serotypes

Dengue viruses (DENVs) have four serotypes: DENV-1, -2, -3 and -4.
All four serotypes are known to be prevalent in Brazil and India.
Each DENV serotype has an outer shell adorned with specialised envelope proteins, called E proteins — akin to the spike protein of coronaviruses.
Even though the four DENV serotypes are very similar, their E proteins are different enough to warrant immunisation against each of the four serotypes.

DENV Antibodies

When weakened DENV is used in a vaccine, it will prompt two broad types of antibodies: type-specific antibodies and cross-reactive antibodies.
Type-specific antibodies are often made in small amounts and recognise only one particular serotype (based on its E proteins) and excel at blocking infections by that serotype alone.
On the other hand, the cross-reactive antibodies are made usually in large amounts and can recognise any of the four serotypes and block an infection — provided they are present at adequate levels.

Antibody-Dependent Enhancement (ADE).

When the cross-reactive antibodies levels drop, they don’t just fail to block a new DENV infection: they enhance it, leading to a severe and potentially fatal form of dengue. This phenomenon is called antibody-dependent enhancement (ADE).
The risk of ADE during dengue vaccination is considered a serious adverse event.
If untreated, it can lead to death.

Phase 3 Clinical Trials of DengiAll

DengiAll is a single-dose dengue vaccine developed by Panacea Biotec in collaboration with the Indian Council of Medical Research (ICMR)
Phase 3 clinical trials completed its enrollment target of 10,335 healthy volunteers in January 2026.
The trial began in August 2024; its participants will be followed for two years post-vaccination. Once all the data have been analysed, the company will approach the drug regulator for market approval.

Qdenga Approval in India

India has officially approved Takeda’s Qdenga (TAK-003), making it the country’s first clearance for a dengue vaccine.
Developed by the Japanese pharmaceutical company Takeda in partnership with Hyderabad-based Biological E, the vaccine is cleared to protect against all four dengue serotypes.
Target Age: Approved for individuals aged 4 to 60 years.
Dosage: Administered in two doses, spaced 3 months apart.
Prior Infection: No pre-vaccination screening or prior history of dengue is required for administration.
Estimated Cost: Expected to be between Rs 6,000 and Rs 12,000 for the full two-dose course.
Availability: Available in both public and private healthcare sectors, with large-scale domestic manufacturing by Biological E underway to make it more widely accessible.