A dengue vaccine, which has been tested in a clinical study in Bangladesh, is showing encouraging results in combating the viral disease.

In a groundbreaking collaboration, researchers from icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh) and the Larner College of Medicine at the University of Vermont (UVM), USA have embarked on the first study of a promising tetravalent dengue vaccine in dengue-endemic Bangladesh, according to a press release on Thursday.

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Their efforts, centred around evaluating the single-dose tetravalent dengue vaccine candidate TV005, have yielded promising results, demonstrating safety and immune responsiveness in both children and adults. These findings have been published in The Lancet Infectious Diseases, it said.

Lead investigator and senior scientist D. Rashidul Haque of icddr,b emphasised on the critical importance of this work for Bangladesh, a nation plagued by severe dengue outbreaks.

Dr Kirkpatrick from UVM highlighted TV005's unique features, including its single-dose administration and its ability to stimulate immune responses against all four dengue serotypes, making it a promising candidate for endemic regions like South Asia.

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As of September 25, 2023, the ongoing outbreak has resulted in 190,758 hospitalizations and over 920 deaths throughout Bangladesh. Currently, fluid management and symptom control are the only available treatments, underscoring the urgency of developing a tetravalent dengue vaccine.

The icddr,b and UVM research teams initiated the "Dengue in Dhaka Initiative (DIDI)" in 2015, marking the first research endeavor on dengue vaccines in Bangladesh.

Their collaborative efforts aimed to advance dengue vaccine development across the country. The study published in The Lancet Infectious Diseases represented a significant phase II randomized and controlled clinical trial, said the release.

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Over three years, starting in 2016, nearly 200 volunteers across four age groups (1-49 years) received either the TV005 vaccine or a placebo. TV005 proved well-tolerated, with most volunteers developing antibodies to all four dengue serotypes, especially those with previous dengue exposure. While the study wasn't designed to assess efficacy, no dengue cases were reported among vaccinated individuals. These results bring the TV005 vaccine closer to widespread use, paving the way for large-scale phase III efficacy trials, it also said.

UVM's Vaccine Testing Centre (VTC) has been evaluating dengue vaccines developed by the US National Institutes of Health (NIH) since 2009. The UVM team, led by Dr Kirkpatrick, collaborated closely with experts like Dr Stephen Whitehead, who played a crucial role in designing the TV005 vaccine. This collaboration has contributed significantly to dengue vaccine research in the United States and beyond, added the release.

Several pharmaceutical companies, including Sanofi and Takeda, have also made progress with tetravalent dengue vaccines, completing their own phase III trials.