Dengue Fever: Symptoms, Travel Risks and UK Vaccine Guidance

In short: Dengue is a viral infection spread by day-biting Aedes mosquitoes across the tropics and subtropics, and cases have reached record levels in recent years. Most infections are mild or cause no symptoms, but a small proportion become severe, and the risk is higher with a second infection. Mosquito bite prevention is the main protection for all travellers. A dengue vaccine is licensed in the UK, but UK guidance currently recommends it mainly for people aged 4 and over who have had dengue before.

This guide, written by a Ready Health prescribing pharmacist and based on UKHSA, NaTHNaC (TravelHealthPro) and NHS guidance, explains dengue symptoms, where it is a risk and what the UK vaccine guidance means for you.

What is dengue fever?

Dengue is caused by four closely related viruses (serotypes 1 to 4), spread mainly by Aedes aegypti and Aedes albopictus mosquitoes. These mosquitoes bite mostly during the day, especially in the early morning and late afternoon, and thrive in towns and cities as well as rural areas. The same mosquitoes can also spread chikungunya and Zika.

Recovering from one type of dengue gives lasting immunity to that type only. A later infection with a different type carries a higher risk of severe dengue.

Where is dengue a risk?

About half the world's population lives in areas at risk, with an estimated 100 to 400 million infections each year. In 2024, a record of more than 14 million cases were reported to the World Health Organization. Risk areas include:

• South and South-East Asia, including India, Sri Lanka, Thailand, Vietnam, Indonesia (including Bali) and the Philippines
• Central and South America and the Caribbean
• Parts of Africa and the Pacific Islands

Europe is not considered endemic, but small numbers of locally acquired cases have been reported in summer and autumn in France, Italy and Spain, where Aedes albopictus has become established.

What are the symptoms of dengue?

Up to 80% of infections cause no symptoms. When symptoms occur, they usually start 4 to 10 days after the bite and include:

• sudden high fever
• severe headache and pain behind the eyes
• muscle and joint pain
• nausea or vomiting
• a rash, often appearing a few days into the illness

Most people recover in about a week. Fewer than 5% develop severe dengue, which can cause bleeding, fluid leakage and shock. Warning signs usually appear around the time the fever settles and include:

• severe tummy pain or persistent vomiting
• bleeding from the gums or nose, or blood in vomit or stools
• rapid breathing, restlessness or extreme tiredness

Seek urgent medical help if any of these occur. There is no specific antiviral treatment; care focuses on fluids and monitoring. Paracetamol is used for fever and pain. Avoid ibuprofen, aspirin and other anti-inflammatory painkillers if dengue is possible, because they can increase the risk of bleeding.

Dengue can look like flu, COVID-19 or malaria. If you develop a fever during or after travel to the tropics, get medical advice promptly and mention your travel, as malaria needs urgent testing.

How can I prevent dengue when travelling?

• Use an effective insect repellent throughout the day, such as one containing 50% DEET (lower strengths can be used for children and in pregnancy, following product directions), applying sunscreen first.
• Wear loose clothing that covers your arms and legs.
• Choose accommodation with screened windows or air conditioning, and use a mosquito net when resting in the day if rooms are not screened.
• Remove standing water around your accommodation where you can.

Is there a dengue vaccine in the UK?

Yes. One dengue vaccine, Qdenga, has been licensed in the UK since 2023. It is a live attenuated vaccine given as two injections three months apart, from age 4. Guidance in the UKHSA Green Book dengue chapter (updated September 2026) is more targeted than the licence:

In clinical trials, the vaccine reduced hospitalisation from dengue in people who had previously been infected. A booster dose has not been established. Women who could become pregnant should avoid pregnancy for at least a month after vaccination. Whether you are vaccinated or not, bite prevention remains essential.

Frequently asked questions

Should I have the dengue vaccine before a holiday to Thailand or Bali?

If you have never had dengue, UK guidance does not usually recommend it. If you have had dengue before, it may be appropriate. A travel health consultation can help you decide.

How do I know if I have had dengue before?

A previous diagnosis or a typical illness after travel to a dengue area may suggest it, but many infections cause no symptoms. A clinician will discuss your history; in some cases a blood test may help.

Can you catch dengue in Europe?

Locally acquired cases have occurred in southern Europe in summer and autumn, but the risk remains low compared with tropical regions.

What painkiller should I take if I think I have dengue?

Paracetamol, following the label. Avoid ibuprofen and aspirin, and seek medical advice.

Key takeaways

• Dengue is spread by day-biting mosquitoes in tropical and subtropical areas, including many popular destinations.
• Most infections are mild, but a second infection carries a higher risk of severe disease.
• Bite prevention during the day is the main protection.
• In the UK, the dengue vaccine is mainly recommended for people aged 4+ who have had dengue before.
• Avoid ibuprofen and aspirin if dengue is possible; use paracetamol and seek advice.

Sources and further reading

• TravelHealthPro (NaTHNaC): Dengue
• UKHSA Green Book: Immunisation against infectious disease
• NHS: Dengue
• WHO: Dengue and severe dengue

Last reviewed: October 2026 by Shamir Patel, Independent Prescribing Pharmacist, Ready Health. This article is general information and does not replace advice from your own clinician. Brand names are trademarks of their respective owners.

Travelling somewhere dengue is common? Ready Health in Standish offers travel health consultations for people in Wigan, Chorley, Horwich, Bolton and the wider North West. A clinician will advise on bite prevention, malaria risk and other vaccines, and whether dengue vaccination is appropriate for you. Book a travel health consultation or call 01257 676001.