Dengue fever – a vaccine-preventable disease
‘Dengue viruses infect around 390 million people a year. Now, for the first time, this mosquito-borne disease is vaccine-preventable.’
The first new vaccine against dengue fever has been given the green light in Mexico and other vaccines against the disease are also in the pipeline.
Update: The first vaccine is now approved in Mexico, Brazil and The Philippines
Dengue is the most common mosquito-borne viral disease of humans that in recent years has become a major international public health concern, according to the WHO.
Transmitted by the main vector, the Aedes aegypti mosquito, there are four distinct, but closely related, viruses that cause dengue.
“There are four distinct, but closely related, serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4),” says the WHO. “Recovery from infection by one provides lifelong immunity against that particular serotype. However, cross-immunity to the other serotypes after recovery is only partial and temporary. Subsequent infections by other serotypes increase the risk of developing severe dengue.”
Vector control has been the primary method of disease control but this can now be supplemented by vaccination.”
The approval in Mexico is expected to be followed by adoption in several South East Asian nations.
Most of those affected live in Asia, Africa and Latin America. However, the disease is now also spreading to non-tropical countries. The number of people living in countries at risk from dengue fever has been estimated at around 3.9 billion – around half the world’s population.
In addition, millions of travellers to those areas are also at risk of being bitten by the disease carrying mosquitos.
Dengue fever was first identified in the 1950s during epidemics in the Philippines and Thailand with nine countries reporting outbreaks by 1970. The number of cases has increased more than fourfold since then and continue to grow.
A 2012 outbreak on the Portuguese island of Madeira was Europe’s first major brush with the disease, while the US has seen cases in Florida and an ongoing outbreak in Hawaii.