Dengue Vaccine Dilemma: Balancing the Health Risks and Financial Benefits
The current debate surrounding Dengvaxia CYD-TDV highlights the urgency for a better dengue vaccine
The first vaccine for the potentially life-threatening dengue virus should only be used in moderate-to high impacted regions. There is a growing public health need for effective, preventive interventions against dengue, a disease caused by four viruses.
An affordable dengue vaccine against these four viruses would represent a major advance for the control of the disease.
A team of researchers, including Dr Mario Recker from the University of Exeter, reviewed the impact and cost-effectiveness of the vaccine, called Dengvaxia, under varying conditions.
This research team found that in areas with high-levels of dengue infection, a routine vaccination programme could reduce the burden of dengue disease on the local population by up to 25 percent.
Moreover, Dengvaxia could potentially be cost-effective in these settings.
However, because the vaccine appears to act similarly to natural infection, its use in areas of low-density dengue disease could potentially see hospital rates increase, significantly reducing any benefit to the local communities.
This is because the vaccine appears to 'prime' individuals who have not yet been in contact with dengue to develop more severe disease symptoms when they get infected with the virus.
The team, led by the London School of Hygiene and Tropical Medicine, suggest that Dengvaxia would be most cost effective, and best reduce the impact on populations, only when infections with dengue are most prevalent.
Dr Recker, an Associate Professor in Applied Mathematics at the University of Exeter's Penryn Campus said: "These results demonstrate although Dengvaxia could reduce the burden of severe and life-threatening disease in countries that suffer most from dengue, it is unlikely to have a major impact on its widespread transmission."
These findings were an important contribution to the evidence base that led the World Health Organization to recommend countries to consider the use of Dengvaxia only in settings with a high burden of dengue disease.
Dengvaxia® (CYD-TDV) is the first dengue vaccine to be licensed. It was first licensed in Mexico in December 2015 for use in individuals 9-45 years of age living in endemic areas. CYD-TDV is a live recombinant tetravalent dengue vaccine developed by Sanofi Pasteur (CYD-TDV), given as a 3-dose series on a 0/6/12 month schedule.
Approximately five additional dengue vaccine candidates are in clinical development, with two candidates (developed by Butantan and Takeda) expected to begin Phase III trials in early 2016.
Dengue is a mosquito-borne viral infection.
The infection causes flu-like illness, and occasionally develops into a potentially lethal complication called severe dengue. Severe dengue is a leading cause of serious illness and death among children in some Asian and Latin American countries. Dengue infects nearly 400 million people across more than 120 countries each year. Most survive with few or no symptoms.
The research paper, the long term safety, public health impact, and cost effectiveness of routine vaccination with a recombinant, live-attenuated dengue vaccine (Dengvaxia): a model comparison study is available at PLOS Medicine online.