Dengue, a viral infection spread by Aedes mosquitoes, has grown from about half a million reported cases in 2000 to a record of more than 14 million in 2024, and it is reaching places that have never had it before.
Updated October 15, 2026. Written from the sources listed below, not independently peer-reviewed.
In 2000, about half a million dengue cases were reported to WHO worldwide. Roughly how many were reported in 2024?
14.4 million
Dengue cases reported to WHO
The highest number ever recorded, from more than 100 countries in all six WHO regions. About 7.7 million were laboratory-confirmed and 52,738 were severe.
Data year 2024. Source: World Health Organization, 2025
11,201
Deaths from dengue reported to WHO
Brazil alone reported 6,321 of them, and Argentina, Mexico and Colombia each reported more than 300,000 cases.
Data year 2024. Source: World Health Organization, 2025
About 4 billion
People at risk of Aedes-borne viruses
WHO's estimate for dengue, Zika, chikungunya and related viruses; the number is expected to rise to 5 billion by 2050.
Data year 2024. Source: World Health Organization, 2024
Unit: million reported cases
Cases reported to WHO by countries, as given in the WHO fact sheet: 505,430 in 2000 and 14.6 million in 2024, about 29 times more. Part of the rise reflects better reporting, and most infections are never reported. WHO's later December 2025 update puts the 2024 total at 14.4 million; reports are revised as countries update them. In January–July 2025, over 4 million cases were reported.
SDG target 3.3 calls for combating communicable diseases by 2030, but dengue has moved in the opposite direction. After reported cases rose to 6.5 million in 2023, WHO graded the global dengue upsurge as a grade 3 emergency, its highest level, in December 2023. In October 2024 it launched a one-year global preparedness and response plan for dengue and other Aedes-borne viruses, running to September 2025 and requiring US$55 million, built on surveillance, vector control, community engagement, clinical care and research.
The Americas accounted for more than 90% of the dengue cases reported worldwide in 2024. Brazil reported over 10 million cases and 6,321 deaths, followed by Argentina (581,559 cases) and Mexico (558,846).
Source: World Health Organization, 2025People infected for a second time, with a different type of dengue virus, are at greater risk of severe dengue than people infected for the first time.
Source: World Health Organization, 2025Small islands can be hit hardest relative to their size: between January and June 2026 the Cook Islands recorded 849 cases, about 5,000 per 100,000 people, and Guyana about 4,200 per 100,000. Eighteen countries, six of them in the African Region, recorded more cases in that period than in the same months of the record year 2024.
Source: World Health Organization, 2026Dengue is spreading into new areas. In 2024, 308 cases were reported to WHO from France, Italy and Spain, and another 1,291 cases and four deaths were recorded in the French overseas territories of Mayotte and Réunion.
Source: World Health Organization, 2025Instead of one “percent solved” score, DO GOOD rates three separate dimensions. A problem can have mature solutions that still reach too few people. These ratings are an editorial reading of the sources on this page, not a measured index.
Has the situation improved in the real world?
LowReported cases rose from about half a million in 2000 to a record 14.6 million in 2024, and dengue is now endemic in more than 100 countries. Fewer cases have been reported since that peak, but outbreaks swing from year to year and the long-run rise has not been reversed.
How mature and validated are the available solutions?
ModerateGood clinical care keeps deaths among people with dengue below 1%, and one vaccine, TAK-003, is recommended by WHO. But there is no specific medicine against the virus, the vaccine is recommended only for children aged 6–16 in high-transmission settings, and mosquito control depends on sustained effort in every household and neighbourhood.
How widely are effective solutions actually used?
LowThe only recommended vaccine is licensed in some countries only, and WHO's main global response plan was a one-year plan with a budget of US$55 million against a threat to about 4 billion people. Wolbachia releases are being used or evaluated in several countries, but WHO has not yet issued a recommendation on them.
Most infections cause no or mild symptoms and are never reported, and WHO notes that case definitions and ascertainment vary substantially between countries. Reporting is improving: since 2024 WHO's global dashboard receives monthly data from 185 countries, territories and areas.
Between January and June 2026 reported cases (1.6 million) were lower than in the same period of 2025, but 18 countries recorded more cases than in the same months of the record year 2024. The mosquitoes are reaching new areas, and WHO links the spread to climate change, urbanisation and population movement.
Dengue is a viral infection passed to people through the bites of infected mosquitoes, mainly Aedes aegypti and Aedes albopictus, which also spread Zika and chikungunya. Most infections cause no symptoms or a mild illness that people manage at home, but some cause high fever and joint pain, and a small share turn into severe dengue, which needs hospital care and can be fatal. There are four types of dengue virus: recovering from one gives lifelong protection only against that type, and a second infection with a different type raises the risk of severe disease. There is no specific medicine against the virus. WHO estimates that about half the world's population is at risk, and in 2024 it received reports of 14.4 million cases and 11,201 deaths, more than in any year before.
The Americas carried more than 90% of reported cases in 2024, with Brazil alone reporting over 10 million, but outbreaks also hit South and South-East Asia, Pakistan and several African countries. Small island states can see very high rates: in the first half of 2026 the Cook Islands recorded about 5,000 cases per 100,000 people. WHO links the spread to mosquitoes moving into new areas, climate change bringing higher temperatures, heavy rainfall and humidity, urbanisation and population movement, as well as weak health systems, gaps in surveillance and humanitarian crises. Severe cases need hospital care, so large outbreaks put heavy pressure on health services that are often already overburdened, and dengue is now reaching countries with no previous experience of it.
Global dengue figures are based on what countries report to WHO, and most infections never reach a clinic. The main measures are:
Reported cases
All suspected and confirmed cases that countries report, including many diagnosed from symptoms without a laboratory test. WHO notes that case definitions and the way cases are found vary substantially between countries, so totals are not fully comparable.
Laboratory-confirmed cases
Reported cases in which a test has confirmed the virus or an immune response to it. In 2024 about 7.7 million of the 14.4 million reported cases were laboratory-confirmed.
Severe dengue and deaths
Cases with dangerous complications that need hospital care, and deaths attributed to dengue. With proper clinical care, fewer than 1% of people with dengue die.
Estimated infections
Because most infections cause no symptoms or only a mild illness, researchers use models to estimate the true number. WHO cites an estimate of 100–400 million infections a year, and one modelling study put the figure at 390 million, of which 96 million showed clinical signs.
What works
Aedes mosquitoes lay their eggs in small amounts of standing water close to homes. Covering, emptying and cleaning water storage containers every week, disposing of solid waste properly, removing other objects that collect water and treating outdoor containers with suitable insecticides reduce the number of mosquitoes.
Limits
It works only if households, schools, businesses and local authorities keep it up week after week, including between outbreaks, and it is harder in fast-growing cities with irregular water supply and waste collection.
What works
There is no specific medicine against the virus, but rest, fluids, paracetamol for fever and pain, and close monitoring for warning signs prevent most deaths: with proper care, fewer than 1% of people with dengue die.
Limits
Dengue can be missed where health workers have little experience of it. Large outbreaks can overwhelm hospitals, and people who take aspirin or ibuprofen face a higher risk of bleeding.
What works
TAK-003 (QDenga), given as two doses three months apart, is the dengue vaccine currently licensed, and WHO recommends it for children aged 6–16 in settings with high dengue transmission. Travellers from non-endemic countries who have had dengue before may also benefit.
Limits
WHO does not recommend it for routine use in children under 6, because of lower efficacy in that age group, nor during pregnancy or breastfeeding or for people with weakened immune systems. It is licensed only in some countries and is meant to add to mosquito control and clinical care, not replace them.
What works
Early warning lets health services prepare beds, staff and supplies and target mosquito control before an outbreak peaks. In 2024 WHO set up a near-real-time global surveillance system that now receives monthly data from 185 countries, territories and areas.
Limits
Surveillance systems in many regions are still at varying stages of development and case definitions differ, so outbreaks can be detected late and comparisons between countries are rough.
Promising, but not proven at scale. The stage shows how far each approach has come; it is not a recommendation.
Releasing Aedes mosquitoes carrying Wolbachia, a naturally occurring bacterium that reduces their ability to transmit dengue, can over time replace the local mosquito population. A WHO advisory group concluded in 2020 that field trials in several countries showed an effect on disease, and several countries are using or evaluating the approach. WHO has not yet issued a recommendation: it has started a new evidence review, and recommendations are expected in late 2027.
Wolbachia releases can also be used to reduce the number of Aedes mosquitoes rather than replace them. WHO's new evidence review will also cover this approach; its effect on disease at scale has not yet been established.
Several additional dengue vaccines are under evaluation. Whether any of them protects a wider range of people than TAK-003, safely and in routine use, will only be clear from trial results and monitoring after licensure.
Since 2024 WHO has run a global dengue dashboard that brings together monthly reports from 185 countries, territories and areas, in place of mostly annual reporting. It makes outbreaks easier to compare, but the data are only as good as national surveillance, which varies widely.
Technology gap
There is no antiviral treatment for dengue. Care relies on fluids, pain relief and careful monitoring, which requires trained staff and hospital capacity that are often stretched during outbreaks.
Technology gap
WHO recommends TAK-003 only for children aged 6–16 in high-transmission settings and not for younger children, pregnant or breastfeeding people or people with weakened immune systems, and the vaccine is licensed in only some countries.
Knowledge gap
Most infections are mild or without symptoms, so many cases are never reported. WHO's own estimate of yearly infections spans a wide range, from 100 to 400 million, which makes it hard to measure progress or compare countries.
Implementation gap
WHO lists fragile and overburdened health systems, political and financial instability, humanitarian crises and large population movements among the drivers of dengue's spread. In these settings, mosquito control and clinical care are hardest to sustain.
Coordination gap
WHO's global response plan for dengue and other Aedes-borne viruses ran for one year, to September 2025, and required US$55 million. Dengue outbreaks recur every year, but responses are often organised and funded as one-off emergencies.
Coordination gap
Several countries are already using or evaluating Wolbachia releases, but WHO does not expect to publish recommendations before late 2027, leaving governments to decide on large investments without global guidance.
Unresolved questions, not vetted breakthroughs. Answering any of them would change what is possible.
How much does Wolbachia population replacement reduce dengue in large, diverse cities, how long does the effect last after releases stop, and what does it cost compared with other control methods?
Can a vaccine safely protect young children, adults and people who have never had dengue against all four virus types, ideally after a single dose, and how should countries choose whom to vaccinate first?
How will rising temperatures, changing rainfall and urban growth change where and when Aedes mosquitoes transmit dengue, and how far ahead can outbreaks be predicted reliably enough to act on?
How many infections, severe cases and deaths go unreported, especially in Africa and in places where dengue is new, and which simple surveillance methods would give countries a more accurate picture?
Once a week, cover, empty and scrub containers that hold water at home, at school or at work, and get rid of rubbish such as tyres and cans that collect rainwater. Encourage neighbours to do the same: Aedes mosquitoes fly up to about 400 metres.
Where dengue occurs, protect yourself against mosquito bites. If you develop a high fever, rest, drink fluids and use paracetamol rather than aspirin or ibuprofen, and ask a health worker which warning signs to watch for: they often appear as the fever goes down and need care straight away.
If you live in a high-transmission area and have children aged 6–16, or you are travelling and have had dengue before, ask a health worker whether the dengue vaccine is available and recommended for you.
Organisations that strengthen local mosquito control, clinical training and surveillance, or that fund vaccine and vector control research, depend on sustained funding. Look for groups that publish evaluations of their work before you give.
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World Health Organization (21 August 2025), published 2025
WHO's overview of dengue. Source of the rise in reported cases from 505,430 in 2000 to 14.6 million in 2024 (with more than 12,000 deaths), endemicity in more than 100 countries, the estimate of 100–400 million infections a year and the modelling estimate of 390 million (96 million clinical), the cases in France, Italy, Spain, Mayotte and Réunion in 2024, the drivers of spread (vectors, climate change, health systems, surveillance, crises, population movement), the breeding-site measures and the statement that QDenga is licensed in some countries.
World Health Organization (26 December 2025), published 2025
WHO's annual global dengue update for 2024. Source of the 14,434,584 reported cases, 7,718,585 laboratory-confirmed, 52,738 severe and 11,201 deaths, the more than 90% share of the Americas, and country figures for Brazil (over 10 million cases, 6,321 deaths), Argentina and Mexico.
World Health Organization (July 2026), published 2026
WHO's mid-2026 global dengue update. Source of the near-real-time surveillance system set up in 2024 (monthly data from 185 countries, territories and areas), the 1.6 million cases and over 700 deaths reported from 89 countries in January–June 2026 (81% in the Americas), totals below 2025, the 18 countries above their January–June 2024 totals (six in the African Region), incidence in the Cook Islands and Guyana, and the caveat that case definitions and ascertainment vary substantially.
World Health Organization, published 2025
WHO's Q&A on dengue. Source of the four virus types and serotype-specific immunity, the higher risk of severe dengue in second infections, the absence of specific treatment and advice to avoid aspirin and ibuprofen, case fatality below 1% with proper care, and WHO's recommendation of TAK-003 (two doses three months apart, ages 6–16 in high-transmission settings; not under 6, in pregnancy, breastfeeding or immune deficiency; possible benefit for previously infected travellers).
World Health Organization (news release, 3 October 2024), published 2024
Launch of the Global strategic preparedness, readiness and response plan for dengue and other Aedes-borne arboviruses (September 2024 to September 2025). Source of the 4 billion people at risk of arboviruses (5 billion by 2050), 6.5 million dengue cases in 2023, the grade 3 emergency of December 2023, the US$55 million requirement and the plan's components.
World Health Organization (departmental update, 11 June 2026), published 2026
Source of the 2020 Vector Control Advisory Group conclusion that Wolbachia population replacement showed epidemiological impact, the absence of a WHO recommendation so far, the new systematic review (also covering population suppression), the Guideline Development Group expected in early 2027 and recommendations anticipated in late 2027.