NEWS: Brazil suspended its dengue vaccination campaign after two reported deathsà raising safety concerns regarding India's indigenous dengue vaccine DengiAll.

DENGUE VACCINE

• Biological vaccine designed to protect against the Dengue Virus (DENV), a mosquito-borne disease transmitted by Aedes mosquitoes.

DENGUE VACCINES GENERATE IMMUNITY

Targeting Envelope (E) Proteins

• Dengue viruses use E proteins to enter human cells.
• Vaccines train the immune system to recognize these proteins.

Antibody Response

Type-Specific Antibodies

• Target one dengue serotype precisely.
• Provide strong and long-lasting protection.

Cross-Reactive Antibodies

• Can bind all four dengue serotypes.
• Offer broader but less precise protection.

Antibody-Dependent Enhancement (ADE)

• When antibody levels decline, some antibodies may fail to neutralize the virus effectively.
• Weak antibodies may facilitate viral entry into immune cells.
• Can increase risk of severe dengue infection during subsequent infections.

NIH-BASED VACCINES (DengiAll & Butantan-DV)

Live-Attenuated Vaccine

• Uses weakened live dengue viruses.
• Generates immune memory similar to natural infection.

Tetravalent Vaccine

• Contains weakened forms of all four dengue serotypes (DENV-1, 2, 3, 4).
• Aims to provide broad protection.

Viral Interference Challenge

• One vaccine strain may replicate more strongly than others.
• Can result in uneven immunity across serotypes.

Efficacy Uncertainty

• Brazilian trials had limited circulation of DENV-3 and DENV-4.
• Protection against these serotypes requires further real-world validation.