Dengue is unusual in that the first infection with any of the four dengue viruses is typically asymptomatic or relatively mild, but if exposed to one of the other four viruses later in life an infected person has a greater risk of developing severe disease. This complex interaction between the four viruses and the human immune response has made developing an effective and safe vaccine against dengue very difficult. At present one vaccine has been licensed, but it can only be given safely to people who have already had dengue at least once.

Since we don't yet have a vaccine that can be widely deployed, controlling the mosquito vectors remains a very important approach in global dengue prevention efforts. In addition to environmental control and use of insecticides, a relatively new strategy that involves infecting mosquitoes with harmless bacteria called Wolbachia that interfere with the ability of dengue viruses to survive inside the mosquito is looking promising. Mosquitoes with different Wolbachia strains have been released in Australia and several countries in Asia and South America and trial results indicate that dengue cases numbers are reduced in places where these mosquitoes have become established in the wild population.