What is Dengue?
Dengue is a mosquito-borne viral infection causing a severe flu-like illness, and sometimes leading to potentially lethal complications known as severe dengue. The virus is transmitted by female mosquitoes mainly of the species Aedes aegypti and, to a lesser extent, Aedes albopictus. Dengue is prevalent in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas.
Why is a Dengue Vaccine Important?
The World Health Organization (WHO) estimates that dengue infects about 390 million people every year. As the incidence of dengue has grown rapidly in recent decades, it is crucial to develop effective preventive measures. A
dengue vaccine offers the potential to significantly reduce the burden of this disease.
How Does the Dengue Vaccine Work?
Dengue vaccines work by stimulating the immune system to produce antibodies against the dengue virus. This is achieved by introducing an inactivated or weakened form of the virus or a part of the virus, such as a protein, into the body. As a result, the immune system learns to recognize and fight the actual virus if the body is exposed to it in the future.
What Are the Available Dengue Vaccines?
The first licensed dengue vaccine,
Dengvaxia (CYD-TDV), was developed by Sanofi Pasteur. It is approved for use in several countries and is recommended for individuals aged 9-45 years who live in endemic areas. Other candidates, such as
TAK-003 by Takeda and
TV003/TV005 by the National Institutes of Health (NIH), are in various stages of development and clinical trials.
Who Should Receive the Dengue Vaccine?
The dengue vaccine is generally recommended for individuals in dengue-endemic areas who have had a prior dengue infection. This recommendation is based on studies that show the vaccine is more effective and safer for those who have previously been exposed to the virus. It's important to consult healthcare professionals for a thorough evaluation before vaccination.
What Are the Benefits and Risks?
Benefits include reducing the incidence of dengue, decreasing the severity of the disease, and lowering the risk of hospitalization due to severe dengue. However, there are
risks involved, such as the potential for severe dengue in those who have not been previously infected. The decision to vaccinate should be based on a careful assessment of these factors.
What Are the Challenges in Developing Dengue Vaccines?
Developing a dengue vaccine poses several challenges due to the complexity of the virus, which has four distinct serotypes. A vaccine must provide immunity against all four serotypes to be effective. Additionally, the risk of antibody-dependent enhancement (ADE), where antibodies facilitate viral entry into cells, complicates vaccine development.
Future Directions in Dengue Vaccination
Research is ongoing to develop more effective and safer dengue vaccines. Advances in
vaccine technology, such as the use of mRNA platforms, offer promising avenues. Collaboration between governments, pharmaceutical companies, and public health organizations is crucial to ensure equitable access to future dengue vaccines.
