India Close To Dengue Vaccine: All About The Phase 3 Trials And More

India is advancing toward its first indigenous dengue vaccine, DengiAll, which has entered the final stage of testing. Developed by Panacea Biotec in collaboration with ICMR, this will be one of the world's first this single-shot vaccine targets all four dengue serotypes amid rising cases. Dengue is a viral infection caused by the dengue virus (DENV), which is transmitted to humans through the bite of infected mosquitoes. According to the World Health Organization (WHO), about half of the world's population is now at risk of dengue, with an estimated 100-400 million infections occurring each year. In 2024, India reported a total of 2,33,519 Dengue cases and 297 deaths, according to the National Centre for Disease Control.

Most people who get infected do not have symptoms. However, those who do, get better in 1-2 weeks. Some develop severe dengue and need care in a hospital. Symptoms of dengue can range from mild fever and joint pain to severe dengue haemorrhagic fever, which can lead to shock and death if untreated. Severe dengue is characterised by plasma leakage, severe bleeding, and organ failure. Major causes of death include shock (Dengue Shock Syndrome), significant haemorrhage, and severe liver/organ dysfunction.

There's no cure for dengue yet, and management focuses on relieving symptoms through rest, hydration, and medications. Every year, India witnesses a surge in dengue cases during the monsoons. Hence, a vaccine could act as a shield against the vector-borne disease.

Global Dengue Vaccines

Dengue vaccine development has faced hurdles due to antibody-dependent enhancement (ADE). It is a phenomenon where, instead of neutralising the virus, antibodies from a previous infection or vaccination bind to a different serotype. This results in higher viral replication and more severe disease.

This was the issue with the world's first licensed dengue vaccine, Dengvaxia, leading to restricted use and the need for new, more balanced vaccine strategies. Dengvaxia and Qdenga are the two main authorised vaccines in the world. These vaccines are designed to protect against all four serotypes of the virus, with a focus on reducing severe disease and hospitalisations.

The DengiAll Vaccine

DengiAll, which is Panacea Biotec's tetravalent live-attenuated vaccine, uses weakened strains of all four DENV serotypes. As a single-dose shot, it simplifies administration compared to other multi-dose vaccines.

Earlier Phase 1/2 trials showed strong immunogenicity and no serious adverse events, generating antibodies against all serotypes. This potentially makes DengiAll India's first indigenous dengue vaccine.

More than 10,000 volunteers across the country are enrolled in the study, overseen by the Indian Council of Medical Research, with the vaccine on track for rollout as early as next year if the trial results are favourable. Speaking to AFP, Syed Khalid Ali, chief scientific officer of Panacea, said, "We will try to get this vaccine out there as soon as possible."

Doctor Ekta Gupta, professor of clinical virology at the Institute of Liver and Biliary Sciences in New Delhi, said, "This vaccine is very much needed right now to control the occurrence of these cases, or at least prevent the severity."

Details Of Phase 3 Trials

The Phase 3 trial was launched in August 2024 and is a multicenter, randomised, placebo-controlled study across 19-20 sites in dengue-endemic zones like Pune, Chennai, Kolkata, Delhi, and Bhubaneswar. It enrolled more than 10,000 healthy adults aged 18-60. These participants were randomly assigned vaccines or placebo.

Enrollment hit 70% by mid-2025 and fully completed by late 2025 and early 2026. Participants will now undergo two-year follow-up for efficacy (dengue prevention), immunogenicity, and safety.

Other Indian Dengue Vaccines

Serum Institute Of India's TetraVax-DV is a live-attenuated tetravalent vaccine. It entered Phase 3 in 2023 across 20+ sites with more than 10,000 volunteers. This vaccine is similar to that of DengiAll in design. TetraVax-DV is developed in collaboration with the US National Institutes of Health (NIH) and aims for an early rollout

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