Dengue
Symptoms, transmission, and current treatments for dengue
Dengue
Symptoms, transmission, and current treatments for dengue
What is dengue?
Dengue is the most widely distributed mosquito-borne viral disease in the world. Driven by climate change, rapid urbanization, and increased population mobility, it continues to spread rapidly. Outbreaks are usually seasonal, peaking during and after rainy seasons. The World Health Organization ranks dengue among the top ten threats to public health.
Caused by a virus that is mostly transmitted by the bite of Aedes aegypti mosquitoes, dengue symptoms can include fever, nausea, vomiting, rashes, fatigue, and intense eye, muscle, joint, and bone pain. For some, dengue infection can become severe, with complications such as bleeding and plasma leakage that can lead to shock, organ dysfunction, and death. Pregnant women, children, older adults, and people with comorbidities are most at risk.
There are four closely related dengue viruses, called dengue serotypes. Although recovery from infection generally provides immunity from the same dengue serotype, it also increases the risk of severe dengue if people are later infected with a different serotype.
What is the impact of dengue?
- • More than half of the world’s population lives in areas at risk of dengue
- • Endemic in over 100 countries around the world, with 86% of cases reported in the Americas
- • 100-400 million estimated infections each year
- • 14.4 million cases reported to WHO in 2024 – the highest ever recorded
- • 11,200 deaths reported in 2024
- • Puts immense pressure on health systems during outbreaks
- • Most dengue infections go unreported as they are asymptomatic, mild and self-managed, or misdiagnosed
What are current treatments for dengue?
There are no specific antiviral drugs to treat dengue infection, or to prevent mild cases from progressing to severe disease.
Acetaminophen or paracetamol can be taken to control muscle aches, pains, and fever. Non-steroidal anti-inflammatory drugs such as ibuprofen and aspirin should be avoided.
Hospitalized dengue patients must be closely observed, and their fluid intake carefully managed, according to strict guidelines. In countries where early detection and specialized medical care for severe dengue is available, the fatality rate is below 1%.
Vaccines are an important component of dengue prevention, but their indications, availability, and recommendations vary by country and population. Qdenga (TAK-003) is currently used in several countries, particularly in settings with high dengue transmission. Additional vaccines are also progressing through national regulatory and implementation pathways. As live-attenuated vaccines, however, they are not currently recommended for high-risk groups such as pregnant women, older adults, and infants. Vaccination therefore complements, rather than replaces, vector control, surveillance, early diagnosis, and appropriate clinical management.
What new treatments for dengue are needed?
Effective treatments that can prevent mild
cases of dengue from becoming severe are urgently needed. Patient care – even
for serious cases – remains purely supportive, placing burdens on health
systems that can become rapidly overwhelmed during outbreaks.
What dengue treatments are we working on?
Together with partners in the Dengue Alliance, we are actively searching for new treatments and have advanced two candidates to Phase II and III clinical trials. We aim to complete development of at least one affordable and accessible dengue treatment solution, advance the pre-clinical development of both host-directed therapies (HDTs) and antiviral candidates, evaluate promising biomarkers that can predict development of severe dengue, and help close the epidemiological data gap on the burden of dengue in Africa.
Find out about our work developing treatments for dengue.
How do you get dengue?
- Insect bites: the virus that causes dengue can be transmitted by the bite of infected female Aedes mosquitoes
- Mother-to-child: transmission from mother to child during pregnancy or childbirth is possible
- Rare cases of transmission via blood products, organ donation, and transfusions have occurred
What are the symptoms of dengue?
Dengue can have no symptoms or cause only mild illness with flu-like symptoms. Moderate dengue infection has symptoms including:
- high fever (40°C/104°F)
- severe headache
- pain behind the eyes
- nausea
- vomiting
- swollen glands
- rash
- muscle, joint, or bone pains so severe that dengue is sometimes referred to as ‘breakbone fever’
Severe dengue occurs when blood vessels become damaged and leak, and the number of platelets (cells that form clots) drops. As a result, severe dengue can cause shock, internal bleeding, bleeding gums or nose, organ failure, and death. The symptoms of severe dengue include:
- severe abdominal pain
- persistent vomiting
- rapid breathing
- bleeding gums or nose
- fatigue
- restlessness
- liver enlargement
- blood in vomit or stool
How is dengue diagnosed?
Dengue can be diagnosed using laboratory or rapid diagnostic tests. During the first days of illness, molecular tests such as RT-PCR can detect dengue virus RNA, while NS1 antigen tests detect a viral protein circulating in the blood. After approximately five days of illness, antibody tests become increasingly useful for identifying a recent infection. Test performance varies by assay, timing of testing, and epidemiological context, and access to reliable diagnostics remains limited in many dengue-endemic settings. Also under development are biomarker tests that could identify individuals at higher risk of developing complications, a much-needed resource that would be useful for treatment optimization during outbreaks.
More information
Last updated: Ocotber 2026
‘Treating a feverish planet: The Dengue Alliance’
Recent years have seen an alarming upsurge in dengue outbreaks all over the world. This short film takes us to Brazil, Sri Lanka, and Thailand to show the devastating impact dengue outbreaks are having across the world.
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