November 3, 2025 : Vietnam’s capital city Hanoi is witnessing a significant surge in dengue fever cases, with 486 new infections reported over the past week, according to the Hanoi Center for Disease Control (CDC). The sharp rise has prompted health authorities to intensify mosquito control measures and public awareness campaigns across the city. The new cases add to the growing dengue burden in Vietnam, with health officials warning that the outbreak may worsen as the country enters its peak mosquito-breeding season, typically from September to November.
The Hanoi CDC reported that dengue cases have now been recorded in nearly all of the city’s 30 districts, with the highest numbers coming from Hoang Mai, Dong Da, Thanh Xuan, and Ha Dong. Health experts attribute the spike to rising temperatures, stagnant water accumulation, and low public participation in preventive activities such as cleaning breeding sites. “The weather conditions have been ideal for mosquito breeding, and community awareness remains low. Unless we act swiftly, these numbers will continue to rise,” said Dr. Nguyen Thi Lan, a senior epidemiologist at Hanoi CDC.
As of early November, the total number of dengue cases in Hanoi has surpassed 8,000, with several severe cases requiring hospitalization. However, no fatalities have been reported in the latest update. Vietnam has been battling dengue fever for decades, but 2025 has seen a sharper uptick in cases compared to previous years. The Ministry of Health (MoH) revealed that the country has reported over 125,000 dengue cases so far this year, with more than 30 deaths nationwide. Southern provinces such as Ho Chi Minh City, Dong Nai, and Binh Duong continue to be among the worst-hit regions, though northern areas like Hanoi are now catching up due to changing weather patterns. “The dengue virus is spreading more widely this year due to increased travel and climate shifts that support mosquito activity,” explained Dr. Pham Duc Minh, a public health researcher from Hanoi Medical University. Dengue fever is caused by the Aedes aegypti mosquito, which also transmits Zika and chikungunya viruses.
Common symptoms include sudden high fever, severe headache and eye pain, muscle and joint pain, nausea, vomiting, and skin rashes. In severe cases, dengue can progress to dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), both of which can be fatal if not treated promptly. Health experts urge residents to seek medical attention immediately if they experience continuous fever, bleeding gums, or persistent vomiting. The Hanoi Department of Health has activated emergency response teams to contain the spread. City authorities have ordered fogging operations, larvicide spraying, and house-to-house inspections to eliminate mosquito breeding grounds, especially in residential areas and construction sites. Community volunteers have joined the effort, distributing educational leaflets and conducting awareness drives about proper waste management and water storage. “People must take responsibility by keeping their surroundings clean. Even a small bucket of water can become a breeding site for mosquitoes,” said Dr. Lan. Authorities are also urging schools and workplaces to conduct weekly cleaning campaigns, covering flower vases, water tanks, and roof gutters — common mosquito breeding hotspots. Major hospitals in Hanoi, including Bach Mai Hospital and Hanoi Medical University Hospital, have reported an increasing influx of dengue patients.
Doctors have been instructed to prioritize early diagnosis and supportive treatment to prevent complications. Temporary fever clinics have been established to reduce overcrowding and speed up testing. Medical staff are being trained to identify early warning signs and manage dehydration — a major risk in dengue patients. Health professionals warn that a second dengue infection can be more dangerous than the first due to a phenomenon known as antibody-dependent enhancement (ADE). “If someone who previously had dengue gets infected again with a different strain, the body’s immune response can worsen the disease,” Dr. Minh explained.
There are four strains of the dengue virus (DEN-1, DEN-2, DEN-3, and DEN-4), and Vietnam has reported circulation of all four this year — making reinfection risks particularly high. Health authorities have emphasized that prevention remains the best protection against dengue. People are advised to cover water containers tightly, use mosquito repellents and nets, wear long-sleeved clothing, avoid water stagnation near homes, and participate in community clean-up campaigns. Dr. Mehra stressed that every household plays a role in controlling dengue’s spread: “Government intervention alone is not enough. Community participation is the most effective tool against dengue outbreaks.” As Hanoi braces for continued rainfall and humidity in the coming weeks, experts fear that dengue numbers could peak in late November if preventive actions are not sustained. The Ministry of Health has reiterated its commitment to nationwide vector control efforts, urging citizens to treat dengue as a serious but preventable disease. “Dengue is no longer a seasonal problem — it’s a year-round threat,” Dr. Minh concluded. “With vigilance and cooperation, we can prevent more lives from being put at risk.”
Summary
Hanoi reports 486 new dengue fever cases, bringing total infections above 8,000. Health authorities intensify mosquito control measures as Vietnam battles rising dengue cases amid changing weather patterns.