NEW DELHI (AFP) — As dengue surges globally, an Indian vaccine candidate has entered the final stage of testing, raising hopes for one of the world’s first single-dose shots against the deadly mosquito-borne disease.

Dengue, which causes severe flu-like symptoms and debilitating body aches, has exploded globally, fueled by rising temperatures and densely populated cities.

The World Health Organization says that almost half the world’s population is now at risk, with 100 to 400 million infections every year. India alone has recorded over one million cases and at least 1,500 deaths since 2021.

Hoping to stem the global epidemic, Panacea Biotec has begun final Phase III trials of its vaccine, DengiAll, which has been pursuing for nearly 15 years.

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 favorable.

“We will try to get this vaccine out there as soon as possible,” Syed Khalid Ali, chief scientific officer of Panacea, told Agence France-Presse in New Delhi.

Doctor Ekta Gupta, professor of clinical virology at the Institute of Liver and Biliary Sciences in New Delhi, said dengue was now considered hyperendemic in India, with all four virus serotypes circulating simultaneously.

“This vaccine is very much needed right now to control the occurrence of these cases, or at least prevent the severity.”

Climate change

Monsoon outbreaks regularly push Indian hospitals to their limits, crowding urban wards and leaving rural regions grappling with late diagnoses and poor access to care.

Higher temperatures and changing rainfall patterns create ideal conditions for Aedes mosquitoes — the vectors of dengue — to reproduce and spread the virus.

Children are particularly vulnerable to the more severe form, called dengue hemorrhagic fever, as they are more likely to suffer low platelet counts and shock.

Participants in Phase III trials, which started in 2024, were randomly assigned to receive either the vaccine or a placebo, with the results expected later this year.

Vaccines against all four dengue serotypes have long posed a scientific challenge. Immunity to one strain does not protect against others, and secondary infections can be more severe.

Most existing candidates require multiple doses.

If approved, DengiAll would become one of the world’s first single-dose dengue vaccines, following Brazil’s approval of a similar shot last year.

It would also be the first such vaccine available in India, where no dengue shot is currently licensed for public use.

“We will be the second (single-dose) vaccine to come out... But in India and several lower-middle-income countries, we will be the first ones to roll out the dengue vaccine,” Ali said.

The candidate is based on a tetravalent strain originally developed by the United States National Institutes of Health.