What is the primary objective of a 'tetravalent' dengue vaccine?

To target all four DENV serotypes simultaneously and equally

To provide immunity against four different strains of mosquito vectors

To provide protection for four distinct age groups

To reduce the dosage requirement to four separate injections

What is 'Antibody-Dependent Enhancement' (ADE) in the context of dengue infection?

The process where antibodies from a first infection increase the severity of a secondary infection by a different serotype

The process where a vaccine completely eliminates the risk of all four dengue serotypes

The mechanism by which the immune system prevents the virus from entering host cells

The natural immunity developed after a single exposure to any dengue serotype

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27 July 2026

Dengue vaccine approval in India

The approval of a new vaccine for a major public health challenge like dengue is a significant development in government health policy and medical technology that directly impacts public health infrastructure.

Notes

India has approved Qdenga, its first dengue vaccine, manufactured by Takeda (Japan), for individuals aged 4-60 years.
The vaccine is tetravalent, intended to protect against all four dengue virus serotypes (DENV-1 to DENV-4).
Dengue infection mechanism: Primary infection creates antibodies; secondary infection by a different serotype can lead to Antibody-Dependent Enhancement (ADE), increasing the risk of severe disease.
Phase-3 trial data (20,000 participants) showed an overall efficacy of 80% in preventing infection and hospitalisation.
Efficacy was 82% for seropositive individuals and 75% for seronegative individuals at baseline.
Safety signal: Seronegative children vaccinated with Qdenga were 25% more likely to be infected by DENV-3 compared to unvaccinated children.
Efficacy against DENV-4 remains unknown due to low/absent case numbers in trials.
Researchers suggest pre-vaccination screening for dengue exposure is necessary to mitigate the risk of ADE in seronegative recipients.

Part of a longer story

This is day 3 of 5 in Approval of Qdenga dengue vaccine in India, which has been running since 21 July 2026. Reading it whole is usually worth more than reading today alone — the exam asks how something developed.

Questions

Discuss the challenges in developing a safe and effective tetravalent dengue vaccine, with specific reference to the phenomenon of Antibody-Dependent Enhancement (ADE). 150 words

Attempt this — 150 words in 8 min

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The approval of new vaccines for endemic diseases requires a balance between public health urgency and clinical safety protocols. In the context of the recently approved dengue vaccine in India, examine the necessity of serological screening and the implications of variable vaccine efficacy across different viral serotypes. 250 words

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Prelims

What is the primary objective of a 'tetravalent' dengue vaccine?

What is 'Antibody-Dependent Enhancement' (ADE) in the context of dengue infection?

Syllabus

Topics

Sources

India’s first dengue vaccine arrives with a crucial safety caveat

250words.in · https://250words.in/daily/2026-07-27/dengue-vaccine-approval-in-india