Dengue fever, a mosquito-borne viral infection, is a significant global health concern, particularly in tropical and subtropical regions. Millions of infections occur annually, placing a substantial burden on healthcare systems. The development of vaccines provides a crucial tool in public health initiatives, offering protection for individuals in or traveling to endemic areas.
The First Dengue Vaccine
The first dengue vaccine was Dengvaxia (CYD-TDV), created by Sanofi Pasteur. This live recombinant tetravalent vaccine uses modified yellow fever virus components to target all four dengue serotypes. Dengvaxia is recommended only for individuals with a documented prior dengue infection. This is due to antibody-dependent enhancement (ADE), where vaccination in those without prior infection can increase the risk of severe dengue if they are later infected. Dengvaxia has been approved in some dengue-endemic countries for individuals aged 9 to 45 years with confirmed prior dengue infection.
The Latest Dengue Vaccine
Qdenga (TAK-003), developed by Takeda, is a newer live-attenuated tetravalent vaccine containing weakened versions of all four dengue virus serotypes. A significant advancement of Qdenga is its broader applicability; it can be administered regardless of an individual’s prior dengue exposure. This eliminates the need for pre-vaccination testing, simplifying its deployment. Clinical trials have shown Qdenga to be generally well-tolerated and to elicit immune responses against all four dengue serotypes in both seropositive and seronegative individuals. Qdenga has received approvals in various regions globally, including the European Union, Indonesia, Brazil, and the United Kingdom, for individuals aged four years and older.
Dengue Disease and Vaccine Necessity
Dengue fever is a viral infection transmitted to humans primarily through the bite of infected Aedes mosquitoes, particularly Aedes aegypti. This disease is prevalent in over 100 countries in tropical and subtropical climates, with an estimated 100 to 400 million infections occurring globally each year. While many dengue infections are asymptomatic or result in mild, flu-like symptoms such as high fever, headache, muscle and joint pains, nausea, and rash, some cases can progress to severe dengue.
Severe dengue, previously known as dengue hemorrhagic fever or dengue shock syndrome, can lead to serious complications including internal bleeding, plasma leakage, dangerously low blood pressure, and organ damage, which can be fatal. There is currently no specific antiviral treatment for dengue, with care focusing on supportive measures. The significant morbidity, mortality, and economic burden associated with dengue underscore the profound public health need for effective preventive strategies, including vaccination.
Vaccine Eligibility and Global Availability
The eligibility for dengue vaccination varies depending on the specific vaccine and national health guidelines. For Dengvaxia, the recommendation is typically for children aged 9 to 16 years who have a laboratory-confirmed history of prior dengue infection and reside in areas where dengue is common. This vaccine requires a three-dose series, with doses administered six months apart.
Qdenga, the newer vaccine, has broader eligibility and is generally approved for individuals aged four years and older, irrespective of their prior dengue exposure. The World Health Organization recommends Qdenga for children aged 6 to 16 years in settings with high dengue transmission intensity. This vaccine is typically given as a two-dose series, with a three-month interval between doses. Vaccine availability differs significantly by country, with prioritization often given to dengue-endemic regions. National health authorities and local epidemiology determine specific recommendations and access, so consulting local health guidelines is always advisable.