The Hanoi office worker said she contracted dengue fever for the second time in 2023, about two years after her first bout. Hong Anh believes she was infected outside her home, despite taking numerous precautions such as using mosquito nets, keeping water containers covered, burning mosquito repellent incense, using essential oils, and keeping windows and doors closed year-round. She even sealed the drains around her house.

However, the disease struck during a casual coffee meeting with colleagues. Hong Anh and two others were bitten by mosquitoes. Within two weeks, Hong Anh developed a high fever and eye pain, leading to a dengue fever diagnosis.

"The illness wasn't severe, but it was debilitating. I had to take a taxi to the hospital for checkups every day. Even waiting for half a day was draining," Hong Anh said.

Since then, Hong Anh has become even more vigilant. She uses an electric swatter to eliminate every mosquito in her house before sleeping. She and her colleagues avoid restaurants and cafes near water features like ponds, lakes, or waterfalls, opting for enclosed spaces. They won't return to a location if mosquitoes are present.

They carry mosquito repellent, wear long-sleeved clothing, shoes, and high socks. They also research and update their mosquito repellent products annually.

Hong Anh uses an electric swatter on the wall before bed to catch any remaining mosquitoes. Photo: NVCC

In TP HCM, the family of 35-year-old Nhu Y also takes extensive measures to combat mosquitoes. They eliminate unnecessary standing water, keep their house clean, and clear out bushes. Like many other families in their neighborhood, they also keep their children indoors and hire mosquito spraying services weekly.

Y explained that their alley in Nha Be district is old, with many ditches and dense vegetation, making it a mosquito haven. During the summer, many children in the neighborhood play together outdoors and get bitten. One child contracted dengue fever and required a long hospital stay.

While they've tried many methods to reduce the risk, even burning wood to create smoke, these proved ineffective. They eventually stopped the mosquito spraying service. "I've resorted to keeping my child occupied indoors with TV and an iPad," Y said, adding that she and her husband have discussed moving to a high-rise apartment to avoid mosquitoes, but they remain uncertain if it will truly solve the problem.

Parents let their children watch TV and use phones to keep them inside and away from mosquitoes. Illustration: Vecteezy

Dengue fever cases, typically peaking between May and November, have seen a sharp increase in 2025 in some areas. According to Ministry of Health statistics from 28/7, TP HCM has over 15,500 cases, a nearly 160% increase compared to the same period last year, with 10 deaths. Ben Tre saw a 346% increase, Tay Ninh 274%, and Dong Nai 192%. Hanoi also reports high mosquito indices in many areas.

The Ministry of Health attributes the surge to several factors: increased rainfall, high humidity, and rising temperatures, which create ideal breeding conditions for mosquitoes. Rapid urbanization and high population density in cities also contribute to the mosquito population growth. The Ministry has repeatedly urged the public to take preventive measures and issued official requests to provinces and localities to strengthen dengue fever control.

Recommended preventive measures include eliminating mosquitoes and larvae and avoiding mosquito bites. People should cover all water containers, sleep under mosquito nets even during the day, wear long clothing, and use mosquito repellent creams, lamps, or electric swatters. Families should spend at least 10 minutes each week checking for and removing mosquito larvae from household water containers, fish tanks, and discarded items that can collect water. Unused containers should be overturned to prevent mosquito breeding.

Dr. Bach Thi Chinh, Medical Director of VNVC Vaccination System, advises against extreme measures based on hearsay, such as excessive screen time for children, which can have negative health and psychological consequences.

Parents take their children for dengue fever vaccinations at the VNVC Vaccination System. Photo: An Hoa

"Lack of physical activity can lead to obesity, cardiovascular disease, diabetes, vision problems, sleep disorders, and abnormal behavior due to one-way online interaction, reducing the ability to focus," Dr. Chinh explained, adding that Aedes mosquitoes prefer dark, humid places indoors and typically bite in the early morning and evening. Extra care should be taken to protect children and the elderly.

Vaccination is also an effective preventive measure. Vietnam currently uses the Qdenga vaccine produced by Takeda Pharmaceuticals (Japan). The vaccine is for children aged 4 and above and adults, requiring only two doses, three months apart. It is over 80% effective in preventing dengue fever infection and reinfection, and reduces the risk of hospitalization by over 90%.

Hoang Duong

*Names have been changed.

At 8 PM on 8/8, the VNVC Vaccination System will host a live online consultation: "How to safely and effectively vaccinate against dengue fever and shingles?". The program will feature the following experts:

Dr. Pham Van Phu, Medical Manager, VNVC Vaccination System

Dr. Hoa Tuan Ngoc, Medical Manager, VNVC Vaccination System.

The program will be broadcast on VnExpress, VNVC, Tam Anh General Hospital, and Nutrihome nutrition clinic media channels. Readers can submit questions here.