Ngoc's family in Son My, Lam Dong, reported that both deceased individuals were admitted to the hospital late, experiencing shock and multi-organ failure. They had contracted dengue fever but did not seek medical attention, opting to take medication at home. When their fever subsided, they believed they had recovered, unaware that this could be the stage when the illness worsens.

Following the local outbreak, health authorities initiated mosquito larva eradication, chemical spraying, and increased case surveillance. Despite these efforts, Ngoc remained concerned, deciding to take her family to VNVC Phan Thiet for dengue vaccination.

"Hearing about people dying around us made me very worried," she said. "Vaccination helps our whole family feel safer, and if we do get sick, the risk of complications might decrease." In 2022, her locality recorded a 23-year-old man who died from dengue fever, along with many other cases.

With young children at home, Ngoc regularly clears trash, eliminates standing water containers, uses mosquito repellent, dresses her children in long-sleeved clothing, and ensures they sleep under mosquito nets day and night. However, her two children still experienced numerous mosquito bites, sometimes with swollen red welts and fever, prompting her and her husband to have them tested to rule out dengue fever.

Ngoc brought her two children, aged 7 and 5, to VNVC Phan Thiet for dengue vaccination. She and her husband have also completed their two vaccine doses. *Photo: Dieu Thuan*

In Dong Phu, Dong Nai, Xuan Di also had her entire family vaccinated after the locality recorded a child's death from dengue fever earlier this year.

The day before their scheduled vaccination, Xuan Di's 4-year-old daughter, Thu, unexpectedly developed a fever and a red rash on her hands and feet. Fearing dengue fever, Xuan Di and her husband took Thu for examination and close monitoring. Doctors determined it was only a fever with a rash. After more than one week of treatment and recovery, the family proceeded with their vaccination plan.

"The days we took our child for examination were very stressful," Xuan Di said. "After that experience, we realized even more the need to proactively prevent illness early."

Doctor Pham Van Phu, Medical Manager at the VNVC Vaccination System, explained that dengue fever is an infection caused by the Dengue virus, transmitted through the bite of an infected female Aedes mosquito. During the one to two initial days, patients typically experience fever, eye pain, headache, rash, nausea, vomiting, and joint pain.

From day 3 to 7, patients may experience a decrease or cessation of fever, but this is also the stage when the illness can become severe. Patients may suffer from thrombocytopenia (low platelet count), hemoconcentration, hemorrhage, shock, multi-organ failure, or even death. Warning signs include abdominal pain, persistent vomiting, lethargy, unusual bleeding, cold extremities, or swollen pain. If patients are complacent, believing that a reduced fever means recovery, they are likely to be admitted to the hospital late.

At a recent seminar on the burden of dengue fever organized by the Ho Chi Minh City Center for Disease Control (HCDC), experts warned that the epidemic pattern is changing. The interval between major outbreaks has shortened to three to four years, compared to approximately five years previously.

In 2026, TP HCM recorded an early increase in cases before the peak of the rainy season. By 31/5, the city had nearly 18,000 cases and four deaths, representing an almost 65% increase compared to the same period in 2025, with cases appearing across all communes, wards, and special zones.

Over half of the cases involved individuals aged 15 years or older. The elderly, pregnant women, and those with underlying conditions such as cardiovascular disease, diabetes, and obesity face a higher risk of severe progression, complications, or death if they contract the disease.

Flooding in TP HCM creates favorable conditions for mosquito breeding, increasing their density and making dengue fever outbreaks more likely. *Photo: Thanh Tung*

According to Doctor Phu, dengue fever can occur year-round, while Aedes mosquitoes breed in containers with long-standing water. Therefore, people need to combine multiple measures: mosquito control, mosquito larva eradication, sleeping under nets day and night, eliminating water-holding items around the house, and proactively preventing the disease with suitable vaccination.

Currently, Vietnam uses a dengue fever vaccine for children aged 4 years to adults, with a schedule of two doses administered three months apart. The vaccine helps prevent all four Dengue virus serotypes—DEN-1, DEN-2, DEN-3, and DEN-4; it reduces the risk of illness by over 80% and the risk of hospitalization by over 90%. Women should be vaccinated three months before pregnancy or at least one month prior.

Doctors advise that vaccines must be fully administered and on schedule to maximize protective efficacy. People should get vaccinated early and not wait until an outbreak occurs in their area or severe cases emerge before starting prevention.

Dieu Thuan