Dengue is resurging across Asia and the Western Pacific, with Vietnam recording more than 50,000 cases in the first five months of 2026, roughly two and a half times the figure for the same period last year, according to World Health Organization monitoring.
Regional totals passed 238,000 cases in the first half of the year, with significant increases also reported in Sri Lanka and the Philippines.
Which countries are worst affected?
Vietnam recorded one of the sharpest increases, logging more than 50,000 cases and five deaths between January and May. Indonesia reported 47,537 cases and 117 deaths through May, although monthly case numbers there have declined since January.
Bangladesh reported 5,924 infections and 18 deaths by the end of June, against 714 infections and one death at the end of May, an eightfold rise in a single month.
| Country | Cases | Period |
|---|---|---|
| Vietnam | 50,000+ | Jan-May |
| Indonesia | 47,537 | To May |
| Bangladesh | 5,924 | To end June |
| New Caledonia | 2,052 | 2026 to date |
| Laos | 1,630 | 2026 to date |
Why are dengue cases rising in Asia in 2026?
Dengue cases have risen sharply across Asia and the Western Pacific during 2026, with regional totals exceeding 238,000 in the first half of the year. Vietnam recorded more than 50,000 cases and five deaths between January and May, approximately two and a half times the total for the same period in 2025. Indonesia reported 47,537 cases and 117 deaths through May, and Bangladesh 5,924 cases and 18 deaths by the end of June. The World Health Organization has attributed the increase to warmer temperatures, higher rainfall and expanding urban mosquito breeding sites. Dengue is transmitted by Aedes mosquitoes, principally Aedes aegypti, which breed in standing water around dwellings and bite during daylight hours. Most infections are mild, but a minority progress to severe dengue, which requires hospital care.
What is driving it?
WHO points to warmer temperatures, increased rainfall and the growth of urban mosquito breeding sites. Aedes aegypti, the principal vector, breeds in small volumes of standing water around houses and bites during the day, which makes bed nets largely ineffective against it.
Monsoon conditions across South and Southeast Asia typically push transmission upward from June through October, meaning the current figures cover the period before the seasonal peak.
Where are cases falling?
The regional picture is uneven. Laos recorded 1,630 cases this year, 12 per cent fewer than the same period in 2025, despite a recent weekly increase. Australia reported 507 notifications through May, with monthly cases declining since January.
Singapore logged 120 cases in epidemiological week 23, a 4.3 per cent increase year on year. New Caledonia has recorded 2,052 cases in 2026, of which 2,047 were locally acquired, indicating sustained community transmission.
Regional health groups signed an agreement in June to coordinate dengue control across borders. Separately, active chikungunya transmission has been reported in the Indian state of Kerala, with more than 2,700 confirmed and suspected cases in early 2026.
What does the trend look like longer term?
Dengue incidence has risen steeply across Southeast Asia over the past two decades, with significant increasing trends recorded in Singapore, Vietnam, Malaysia and the Philippines. Cases fell during the COVID-19 pandemic and rebounded sharply from 2023 onward.
There is no specific antiviral treatment for dengue. Clinical management relies on fluid replacement and monitoring for warning signs of severe disease, which makes early presentation and functioning hospital capacity the main determinants of survival.
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Sources for this report
The Redline News Desk
The Redline News desk files and edits world reporting. Every story carries the sources it was built from, and corrections are published on the story itself.
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