If dengue outbreaks once typically peaked between September and December, health authorities now report unusually high case numbers from the very beginning of the year. Ho Chi Minh City alone has already recorded four dengue-related deaths.

According to the Department of Disease Prevention under the Ministry of Health, Vietnam recorded nearly 50,000 dengue fever cases during the first months of 2026, approximately 2.5 times higher than the same period last year. The disease has appeared earlier than usual, spread to a growing number of northern localities and is showing increasingly unpredictable patterns.

Speaking at a recent forum titled "Dengue Fever: Unpredictable Developments in Vietnam", jointly organized by the Department of Disease Prevention and Suc Khoe & Doi Song newspaper, Dr. Angela Pratt, Representative of the World Health Organization (WHO) in Vietnam, said climate change is creating more favorable conditions for the proliferation of Aedes aegypti mosquitoes.

She added that rapid urbanization, high population density and inadequate environmental infrastructure are also contributing to increased transmission risks.

Public complacency remains a concern

Vo Hai Son, Deputy Director General of the Department of Disease Prevention, noted that Vietnam continues to record hundreds of thousands of dengue infections annually. While outbreaks traditionally followed a roughly three-year cycle, recent developments suggest that pattern is changing.

"A notable feature of 2025 and the first months of 2026 is that dengue fever has emerged earlier than usual. In the past, case numbers generally surged between September and December, but many localities are now reporting high infection rates from the start of the year," Son said.

According to Associate Professor Dr. Nguyen Thanh Hung, Vice President of the Vietnam Pediatric Association and former Director of Children's Hospital No. 1 in Ho Chi Minh City, approximately 60-70% of dengue cases in southern Vietnam more than a decade ago involved children under the age of 15. Today, infection rates among children and adults are nearly equal.

Medical experts say one reason the disease remains dangerous is widespread complacency. Many people mistakenly believe that once a fever subsides, recovery has begun. In reality, dengue often progresses in the opposite direction.

"The period between the third and fifth day of illness, when fever decreases or disappears, is often the most dangerous stage," Hung explained. "This is when severe complications such as dengue shock syndrome, major bleeding or multi-organ failure may occur. Many patients arrive at hospitals too late because they assume they are recovering, significantly increasing the risk of death. As there is still no specific treatment for dengue, early detection of warning signs, close monitoring and proper care remain the key factors in reducing complications and fatalities."

New tools in the fight against dengue

Alongside mosquito control measures, larval elimination campaigns and surveillance efforts, Vietnam's healthcare sector is gradually incorporating new technologies into dengue prevention strategies.

Dr. Angela Pratt said advances in technology and artificial intelligence are significantly improving early disease warning systems. Combining meteorological, environmental and epidemiological data can help authorities forecast outbreak risks more accurately, allowing local governments to implement preventive measures more proactively.

Vaccination is also regarded as a major breakthrough in dengue prevention. Experts say vaccines can reduce the risk of infection, lower the likelihood of severe disease, ease pressure on healthcare systems and ultimately help reduce mortality.

N. Huyen