Qdenga dengue vaccine nears rollout in India: What experts want you to know

With dengue rising across regions, doctors break down the vaccine's benefits, safety, and why mosquito control still remains essential

As climate change reshapes weather patterns, it is also quietly expanding the footprint of vector-borne diseases like Dengue across regions that were once less affected. Warmer temperatures, erratic rainfall, and rising humidity are creating ideal breeding conditions for the Aedes mosquito, allowing dengue to spread faster and last longer through the year. This growing burden is putting pressure on public health systems, especially in densely populated countries like India. 

Against this backdrop, the arrival of a new vaccine, Qdenga, is being seen as a crucial development. Japanese biopharma giant Takeda’s dengue vaccine, TAK-003, marketed as Qdenga, has recently been cleared by the Subject Expert Committee (SEC) under the Drugs Controller General of India (DCGI) for use in individuals aged 4 to 60 years, as reported by The Hindu. 

 

The panel has also mandated post-marketing studies within six months of rollout to assess safety and effectiveness in the Indian population, which will be key to understanding how the vaccine performs across regions and circulating dengue strains. 

Experts say that while the vaccine offers promise, understanding its role, effectiveness, and limitations is key before it becomes widely available.

What is Qdenga and why is it different?

Qdenga is a vaccine made using a weakened form of the virus and is designed to protect against all four types of dengue. It is given in two doses, spaced three months apart. 

It has been evaluated in large global trials involving over 28,000 participants and has already received approval in more than 40 countries. 

Dr Rashmi Khadapkar, GM of Research and Development and Section Head of Molecular Infectious Diseases at Agilus Diagnostics, explains that its biggest advantage lies in its broader usability. 

“Qdenga can be given irrespective of prior dengue exposure, without the need for pre-vaccination screening, making it more suitable for public health programmes.” 

This marks a significant shift from Dengvaxia, which required prior infection due to safety concerns. 

Dr Amitabh Parti, Senior Director and Unit Head of Internal Medicine at Fortis Gurgaon, highlights that protection against hospitalisation remains strong across both groups. 

“Against dengue hospitalisation, Qdenga showed 85.9 per cent efficacy in seropositive individuals (those previously infected) and 79.3 per cent in seronegative individuals (those never infected), reassuringly high in both groups for the most critical outcome.”

Who is likely to get it first?

While India’s final rollout strategy is still awaited, experts expect a targeted approach rather than immediate universal access. 

Likely priority groups include:

• People living in high-burden urban and semi-urban areas
• Children and adolescents, who face higher risk
• High-exposure groups such as healthcare workers

Dr Khadapkar notes that globally, the vaccine is approved for individuals aged six years and above, particularly in regions where dengue transmission is high. This aligns with international recommendations to introduce it first in high-transmission settings.

How effective is the vaccine?

Experts share that Qdenga offers meaningful protection, especially against severe outcomes.

• Around 80 per cent protection against symptomatic dengue in the first year
• About 61 per cent protection over longer follow-up
• Nearly 84–90 per cent reduction in hospitalisation

These numbers highlight that while the vaccine may not completely prevent infection, it significantly lowers the risk of severe disease, which remains the primary public health concern.

What about safety and side effects?

So far, evidence points to a favourable safety profile. 

Common side effects include:

• Mild fever
• Pain at the injection site
• Headache or fatigue

Serious adverse events are rare, and no major long-term safety concerns have emerged. However, ongoing monitoring continues, particularly in people who have never had dengue before. 

Experts say this improved safety profile makes Qdenga more suitable for large-scale public health use compared to earlier vaccines. 

They caution that effectiveness varies by strain. Dr Parti notes that while the vaccine is highly effective against DENV-2, it shows limited or inconclusive protection against the DENV-3 and DENV-4 variants in those without prior exposure. This is why global recommendations prioritise high-transmission areas where most people have already encountered the virus.

Will the vaccine be enough to stop dengue?

Despite the optimism, experts emphasise that vaccination alone will not eliminate dengue. 

“Vaccination is a powerful addition, but not a replacement for integrated dengue control,” says Dr Parti. 

This is because the disease is transmitted by the Aedes mosquito, which also spreads infections such as Chikungunya, Zika, and Yellow fever, none of which are covered by this vaccine. 

Experts underline that dengue control must remain multi-pronged:

• Eliminating mosquito breeding sites
• Using personal protection such as repellents
• Ensuring early diagnosis and timely treatment

Dr Khadapkar reinforces this, noting that vaccination should be viewed as an additional layer of protection rather than a standalone solution. 

As India prepares for its possible rollout, experts stress that success will depend not just on vaccination, but on sustained public health measures and awareness. 

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This report is for informational purposes only and is not a substitute for professional medical advice.