World's most advanced dengue vaccine candidate shows promise in phase 3 trial

July 11, 2014

The first dengue vaccine candidate (CYD-TDV) to reach phase 3 clinical testing has shown moderate protection (56%) against the disease in Asian children, according to new research published in The Lancet.

Dengue is a mosquito-borne disease that infects around 390 million people each year, of whom about 96 million suffer from symptomatic infection. WHO estimates that the global burden of has risen 30-fold over the past 50 years, with over half of the world's population at risk of the disease.

There is no licensed vaccine available to treat or prevent , and efforts to develop one have been complicated by the fact that dengue is caused by four distinct dengue viruses, and a vaccine must target all four serotypes (DENV 1–4).

This phase 3 trial took place in dengue-endemic areas across five countries in Asia, a region that accounts for over 70% of the global dengue burden. The study involved 10 275 healthy children aged 2 to 14 years who were randomly assigned to receive three injections of the CYD-TDV vaccine (6851) or a placebo (3424) at 0, 6, and 12 months, and followed for up to 2 years.

The researchers recorded 250 dengue cases more than 28 days after the third injection—117 in the vaccine group and 133 in the , demonstrating an overall protective efficacy of 56.5%.

The vaccine also showed 88.5% efficacy after 3 doses against severe disease (dengue haemorrhagic fever) which leads to hospitalisation for over half a million people (mostly children) every year, and 67% against dengue-associated hospitalisation.

The researchers found that the vaccine gave low protection (35%) against DENV 2, but more than 75% protection against DENV 3 and 4, and 50% against DENV 1.

The vaccine was generally well tolerated. A total of 647 serious adverse events were reported, 402 (62%) in the vaccine group and 245 (38%) in the placebo group.

According to lead author Dr Maria Rosario Capeding from the Research Institute for Tropical Medicine in the Philippines, "Our results suggest that vaccination with CYD-TDV can reduce the incidence of symptomatic dengue infection by more than half and importantly reduced severe disease and hospitalisations. This candidate vaccine has the potential to have a significant impact on public health in view of the high disease burden in endemic countries."

Writing in a linked Comment, Professor Annelies Wilder-Smith from Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore says, "Perhaps the most interesting finding of this trial was that efficacy after at least one dose was almost as high as that after three doses…Because three doses 6 months apart is an inconvenient and costly immunisation schedule for scale up in national programmes, the question of whether sufficient efficacy can be achieved with a lower number of doses deserves further assessment."

She adds, "With an estimated 96 million clinically apparent dengue infections annually, a reduction by half would present a significant public health benefit that would support dengue vaccine introduction….Whether the armamentarium of alternative vaccine candidates presently in the pipeline (including inactivated, live attenuated, chimeric, recombinant, subunit and DNA vaccines) will improve efficacy beyond 56% remains to be established. For the moment, the CYD-TDV vaccine is the best we have; however, with 56% efficacy it will never be a single solution. Continued support for the development of other novel strategies including drugs, improved case management, insecticides, and new approaches to vector control, is needed before effective dengue control becomes a credible prospect."

Explore further: Scientists make dengue vaccine breakthrough

Related Stories

Scientists make dengue vaccine breakthrough

September 10, 2012

Dengue is one of the most widespread mosquito-borne viral diseases in the world, with WHO estimating that around half of the world's population are currently at risk. While infection usually causes flu-like symptoms, it can ...

Concerns over cost of dengue vaccine lessened with new study

June 28, 2012

Research funded by the Dengue Vaccine Initiative (DVI) involving an economic analysis of producing a tetravalent dengue vaccine shows that the cost could be as low as $0.20 per dose with an annual production level of 60 million ...

Dengue vaccine to be tested in India

November 19, 2012

French health care giant Sanofi Pasteur will soon test a vaccine against dengue fever in India amid concerns about the increasingly global spread of the disease, reports said Monday.

Recommended for you

Zika in fetal brain tissue responds to a popular antibiotic

November 30, 2016

Working in the lab, UC San Francisco researchers have identified fetal brain tissue cells that are targeted by the Zika virus and determined that azithromycin, a common antibiotic regarded as safe for use during pregnancy, ...

Zika and glaucoma linked for first time in new study

November 30, 2016

A team of researchers in Brazil and at the Yale School of Public Health has published the first report demonstrating that the Zika virus can cause glaucoma in infants who were exposed to the virus during gestation.

Flu forecasts successful on neighborhood level

November 30, 2016

Scientists at Columbia University's Mailman School of Public Health developed a computer model to predict the onset, duration, and magnitude of influenza outbreaks for New York City boroughs and neighborhoods. They found ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.