Dengue
Dengue is an infection caused by the dengue virus of which there are four different types (serogroups) DENV-1, DENV-2, DENV-3 and DENV-4. The disease is spread through the bite of an infected mosquito. The mosquitoes that spread dengue usually breed in urban areas close to human habitation and are most active during daylight hours. Although unpleasant, dengue is usually a self-limiting illness. However, a small, but significant, number of people can develop more life-threatening infection (severe dengue).
The disease is common in the tropics. Affected areas include the Caribbean, South and Central America, Africa, Asia and the Pacific Islands. Although less common, outbreaks are increasingly being reported outside tropical areas, including in Europe, with locally acquired cases reported in Croatia, France, Italy, Madeira and Spain.
Dengue does not occur naturally in the United Kingdom (UK) but is reported in travellers returning from dengue affected areas. Cases of dengue in UK travellers are increasing, with most reported in travellers who visited Asia, Central and South America or the Caribbean. Country-specific information on dengue is available on our Country Information pages and current dengue outbreaks are listed on our Outbreak Surveillance section.
All travellers to dengue endemic countries are at risk of dengue infection. The chance of becoming infected with dengue is determined by several factors, including destination, length of exposure and season of travel. Risk is thought to be higher during periods of intense mosquito feeding activity (two to three hours after dawn and during the early evening). Travellers, who spend long periods in areas where dengue is common, are at increased risk, but even short-term visitors can be infected.
Approximately 40 to 80 percent of people infected with dengue remain symptom-free. If symptoms do occur, the illness usually begins abruptly with a high fever, and is often accompanied by a severe headache, muscle and joint pain, nausea, vomiting and a rash. Most infections are self-limiting, with a rapid recovery three to four days after the rash appears.
A small number of people develop more severe illness with symptoms which can include dangerously low blood pressure (shock), fluid build-up in the lungs and severe bleeding. There is no specific drug treatment for severe dengue illness, although hospital admission and careful management of fever, fluid balance and pain can help with recovery. If left untreated, severe dengue illness can be fatal. With good medical care, death due to severe dengue is typically less than one percent.
Prevention
Travellers can check our Country Information pages for information on the risk of dengue at their destination. Mosquito bite avoidance is recommended. As dengue is spread by day-biting mosquitoes, particular care with bite avoidance is advised during the day, especially around dawn and dusk.
A vaccine, Qdenga®▼ has been licensed in the UK for the prevention of dengue disease in individuals from 4 years of age.
The UK Joint Committee on Vaccination and Immunisation (JCVI) has advised that Qdenga®▼ vaccine can be considered for individuals aged 4 years of age and older who have had dengue infection in the past and are:
- planning to travel to dengue where there is a risk of dengue infection or areas with an ongoing outbreak of dengue
or
- exposed to dengue virus through their work, for example, laboratory staff working with the virus.
Exceptionally, vaccination can be considered in those who have not had dengue in the past. In these situations, further expert advice should be considered.
Blood tests for previous dengue infection may not be 100 percent reliable and assessment must be made of previous tests for dengue, likely exposure and clinical history. In the UK, tests for previous dengue infection are usually offered privately, (a fee is charged to the individual being tested). Guidance on investigating previous dengue infection and use of Qdenga®▼ is available in the UKHSA 'green book' Immunisation against infectious disease, dengue chapter.
Qdenga®▼ is a live vaccine (it contains live, attenuated dengue virus) and cannot be given to travellers who are immunosuppressed (have a weakened immune system), pregnant or breastfeeding. This vaccine is also contraindicated (cannot be given) for those with hypersensitivity to any component of the vaccine and for children under four years of age.
Resources
- More detailed information on can be found in our dengue factsheet
- UKHSA: Dengue: guidance, data and analysis
- UKHSA: Dengue chapter 'green book' Immunisation against infectious disease
- Joint Committee on Vaccination and Immunisation (JCVI): Minutes of meeting 7 February 2024
- World Health Organization (WHO): Fact sheets: dengue and severe dengue
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Recent News on Dengue
Changes to the Country Information pages: dengue vaccine recommendations
NaTHNaC has reviewed and updated the dengue country-specific information and vaccine recommendations
Updated: 02 May 2025Mosquito and insect spread infections in the Caribbean
An increase in cases of mosquito and insect spread infections have been reported in the Caribbean region
Updated: 24 December 2024Dengue 'green book' chapter published
A new dengue chapter in the 'green book' (Immunisation against infectious disease) has been published
Updated: 15 October 2024Insect spread illness reminder for pregnant travellers
Information and advice for pregnant women planning travel to countries with a risk of insect, mosquito and tick spread infections
Updated: 08 October 2024Recent Dengue Outbreaks
Dengue in Martinique
As of 29 March 2026, 1,009 cases of dengue fever have been reported in Martinique since the start of 2026. DENV3 has been recorded. Please see our Topics in Brief article for further details on dengue.
Dengue in Bolivia
As of 22 March 2026, 36,007 suspected cases of dengue have been reported in Bolivia since the start of 2026. This represents a large increase compared to the same period in 2025. Serotypes DENV1 and DENV2 have been recorded. Please see our Topics in Brief article for further details on dengue.
Dengue in Maldives
As of 15 April 2026, 1,908 cases of dengue have been reported in the Maldives since the start of 2026. This represents an increase compared to the same period in previous years. Cases has been recorded across all Atolls. Please see our Topics in Brief article for further details on dengue.
Dengue in Tonga
As of 20 April 2026, a total of 24 laboratory confirmed dengue cases have been reported in Tonga for 2026. The Ministry of Health have declared a dengue outbreak following an increase in confirmed and suspected cases, along with evidence of community transmission across Eua, Ha‘apai and Tongatapu. Please see our Topics in Brief article for further details on dengue.
