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The HinduJuly 25, 2026

On guard: on India and the Qdenga dengue vaccine

The CDSCO’s approval of the Qdenga dengue vaccine — the first in India’s history — follows the vaccine’s licensing in over 40 countries and a WHO prequalification, and some of the country’s worst dengue years vis-à-vis the disease’s burden, although that is evidence of better surveillance as well. The Aedes mosquitoes that spread the disease are expanding into semi-urban and rural districts, where conventional vector control is harder to sustain. The time to develop the vaccine itself is understandable. The four antigenically distinct dengue serotypes and the possibility of a ‘second infection’ by a different serotype producing more severe disease through antibody-dependent enhancement mean that an effective shot has to induce strong immunity against all four at once. This constraint nearly derailed the first licensed dengue vaccine, Dengvaxia, and the controversy in the Philippines in 2017 prompted greater regulatory caution. The design of Qdenga, by Japan-based Takeda , differs from that of Dengvaxia and, unlike the latter, can be administered without screening for a prior dengue infection. Its protection against the serotypes varies from highest against DENV-2, followed by DENV-1, while uncertainty remains regarding protection against DENV-3 and DENV-4 in people without prior exposure to dengue. This is concerning because while DENV-2 is more common in India, DENV-3 prevalence is increasing. If the DENV-3 serotype dominates the 2026 monsoon season, Qdenga’s impact could be substantially lower than anticipated, especially if many recipients are dengue-naïve. Qdenga also requires two doses across three months apart. Clinical data suggest that the first dose protects unevenly, with stronger evidence against DENV-1 and DENV-2 than DENV-3 and DENV-4. If a seronegative person takes the first shot on July 1, when the monsoon begins, and encounters DENV-3 in August, the shot may not suffice to prevent severe illness. Ensuring the highly mobile migrant workforce receives its second dose will be significantly difficult, too; those falling through the cracks may also be exposed to concerns raised in the TIDES trial of a ‘negative efficacy’ against hospitalisation related to DENV-3 among seronegative children. Finally, following Takeda’s tiered pricing strategy worldwide, Qdenga may be too expensive for people living in dense urban slums with poor drainage. To ensure sufficient uptake among the populations at greatest risk, the government must negotiate a lower price. In the end, administering a dengue vaccine properly in a population is no less tricky than developing a vaccine against dengue, and the Qdenga rollout should give no cause for complacency. Published - July 25, 2026 12:10 am IST Read Comments Copy link Email Facebook Twitter Telegram LinkedIn WhatsApp Reddit READ LATER SEE ALL Remove Related Topics vaccines / India / World Health Organization / disease / Japan / Philippines / Monsoon / migration / labour / government

Key GK Takeaways for CLAT
  • 1India's drug approval architecture rests on the Central Drugs Standards Control Organisation functioning under the Drugs and Cosmetics Act, 1940, with the Drugs Controller General of India as the statutory approving authority for new vaccines. Qdenga's approval as India's first licensed dengue vaccine shows domestic regulatory sign-off increasingly following international benchmarks like WHO prequalification and licensing abroad. This sequencing raises governance questions about whether India's regulatory capacity is being used proactively or merely ratifying decisions already validated overseas.
  • 2On domestic policy, the National Vector Borne Disease Control Programme has for over two decades relied primarily on source reduction and Aedes mosquito control rather than vaccination, even as dengue cases in India have risen substantially over the past decade per government surveillance data. Qdenga's arrival forces a policy shift toward integrating vaccination into this programme, but the editorial's own caution about the DENV-3 mismatch suggests vaccination cannot yet replace vector control as the primary strategy. Budgetary allocation between vaccine procurement and continued sanitation-based vector control will be a key policy tension going forward.
  • 3Qdenga's approval falls under the New Drugs and Clinical Trials Rules, 2019, framed under the Drugs and Cosmetics Act, 1940, which empower the Central Licensing Authority to grant marketing approval based on foreign clinical data supplemented by local bridging studies. The Philippines' 2017 Dengvaxia controversy, where hundreds of thousands of schoolchildren were vaccinated before safety concerns emerged, led to a landmark Ombudsman probe and criminal charges against health officials, and remains the global cautionary precedent shaping regulatory caution. India's CDSCO is expected to mandate robust post-marketing pharmacovigilance for Qdenga under the Drugs Rules.
  • 4Scientifically, dengue's four serotypes create the phenomenon of antibody-dependent enhancement, where a second infection by a different serotype can be more severe than the first, a mechanism first documented during dengue epidemics in the 1970s. Economically, Takeda's tiered global pricing means Qdenga could be priced out of reach for India's urban poor without government subsidy or inclusion in the Universal Immunisation Programme. With dengue cases reported across nearly every state and Union Territory, effective and equitable rollout could meaningfully reduce the substantial annual economic burden dengue imposes through treatment costs and lost productivity.

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