Vietnam reports over 50,000 dengue cases in 5 months as outbreak patterns shift

The figures were presented at a dengue fever forum in Hanoi ahead of ASEAN Dengue Day (June 15).

Vo Hai Son, deputy director of the Ministry of Health's Department of Preventive Medicine, said dengue infections remained elevated in November and December 2025 instead of declining toward the end of the year as they had in previous years.

Health experts said outbreaks were no longer confined to specific regions or age groups. 

Cases have been reported across most parts of the country, including northern provinces that historically recorded relatively few infections.

Angela Pratt, the World Health Organization's representative in Vietnam, said climate change, rapid urbanization, and increasingly difficult-to-predict epidemiological trends were driving changes in dengue transmission.

Son said Vietnam recorded about 371,000 dengue cases in 2022, while annual infections in recent years averaged around 150,000. 

He said prolonged periods of hot, humid weather, and rainfall had created favorable conditions for mosquito breeding.

He also said the DENV-2 serotype was currently dominant, increasing the risk of severe illness.

According to Nguyen Thanh Hung, vice-president of the Vietnam Pediatric Association, the age distribution of dengue cases had shifted. 

More than a decade ago, children under 15 accounted for 60 percent to 70 percent of cases in southern Vietnam, but infection rates among children and adults are now nearly equal, he said.

Hung said severe complications can occur between the third and fifth day of illness, when fever may subside and patients believe they are recovering. 

He said delayed treatment can increase the risk of shock, severe bleeding, multiple organ failure, and death.

Pratt said artificial intelligence and other technologies were helping strengthen early warning systems and improve forecasting of dengue transmission alongside traditional mosquito-control and disease-surveillance measures.

She said Vietnam had licensed a dengue vaccine and was preparing pilot programs to evaluate its potential inclusion in the national immunization program.

Son said health authorities were also studying pilot vaccination programs in selected localities while continuing mosquito-control efforts, public awareness campaigns, treatment-capacity improvements, and the use of environmental and weather data to support outbreak forecasting.