Dengue vaccine: Phase-3 of trial begins in Rohtak

The first phase III clinical trial for dengue vaccine in India was kickstarted on Wednesday, with the first person receiving a shot at Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences (PGIMS), Rohtak.

The vaccine called DengiAll, which works against all four serotypes of dengue, has been developed by Panacea Biotech.

The trial will be conducted at 19 sites across 18 states and Union Territories. It will follow 10,335 healthy adults for a period of two years. The trial is primarily funded by the Indian Council of Medical Research, with the company partially bearing the expenses.

“The initiation of this Phase 3 clinical trial for India’s first indigenous dengue vaccine marks a critical advancement in our fight against dengue. It reflects our commitment to protecting our citizens from this pervasive disease and underscores India’s capabilities in vaccine research and development,” Union Health Minister JP Nadda said.

Panacea’s vaccine uses live, weakened versions of all four dengue serotypes. These weakened versions of the virus were developed by the National Institute of Allergy and Infectious Diseases in the US— they deleted parts of the genetic code of DENV1, DENV3, and DENV4 and then genetically engineered a DENV2 backbone using parts from the weakened DENV 4, on which the others were tacked.

One of the biggest challenges with developing a dengue vaccine is that the four serotypes of the infection offer very little protection against each other, meaning one individual can be infected repeatedly with different serotypes. More importantly, it can lead to antibody dependent enhancement (ADE) — a person with low levels of antibodies against one serotype of dengue, getting a more severe infection with another serotype.

ADE was the reason for controversy surrounding the first dengue vaccine in the world. Only after a vaccination programme had been rolled out in the Philippines was it found that the vaccine could actually increase the risk of severe disease in the people who had not been infected before.

The Serum Institute of India has used the same weakened virus from the United States to develop another vaccine candidate that has completed initial phases of trial. The company will conduct a large phase III trial in collaboration with ICMR in children between the ages of 2 and 18 years.

The same technology has also been used by Indian Immunologicals Limited to develop a vaccine that is undergoing initial phases of human trials. Hyderabad-based vaccine manufacturer BiologicalE has partnered with the global pharmaceutical company Takeda to produce its dengue vaccine, which is based on the same principle as the NIAID vaccine.

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