Warning of the risk of dengue fever outbreak out of season

Although the dry season in the South has not ended, unseasonal rains have appeared, creating favorable conditions for the development of disease-transmitting agents, especially Aedes mosquitoes - the vector of dengue fever.

Although the dry season in the South has not ended, unseasonal rains have appeared, creating favorable conditions for the development of disease-transmitting agents, especially Aedes mosquitoes - the vector of dengue fever.

Experts warn that dengue fever could flare up, even though it is not the rainy season. According to the National Center for Hydro-Meteorological Forecasting, it is currently the dry season in the Southern region, and unseasonal rains have begun to appear.

Although it is not the rainy season yet, the dengue fever epidemic situation is alarming.

Climate change and the La Nina phenomenon have increased the rate of unseasonal rains, bringing high humidity, creating favorable conditions for Aedes mosquitoes - the main agent causing dengue fever. At the same time, the North is entering a humid period, with high humidity, causing mosquito eggs to develop rapidly.

The concern is that Aedes eggs can survive in dry environments, waiting for the right time to breed. Rain creates stagnant water, which is an ideal place for mosquito eggs to hatch and grow, increasing the risk of disease spread.

Although it is not yet the rainy season, the dengue fever epidemic situation is alarming. In the first two months of 2025 alone, Ho Chi Minh City recorded 4,213 cases of dengue fever, an increase of 125.3% compared to the same period in 2024.

This shows that dengue fever is no longer just a disease of the rainy season, but can occur all year round. The situation in the North is no better, when Hanoi recorded 137 cases of dengue fever during the cold spell in early 2025. This is something that has not happened in many years.

Prof. Dr. Vu Sinh Nam, Senior Advisor on dengue fever, National Institute of Hygiene and Epidemiology, said that dengue fever prevention and control in Vietnam still faces many difficulties.

Factors such as climate change, increased trade, urbanization and the lack of specific treatment all contribute to the increased spread of the disease. In addition, dengue fever begins with non-specific symptoms such as fever, headache, muscle pain, which can easily be confused with other diseases, making timely diagnosis and treatment difficult.

Prof. Dr. Vu Sinh Nam also emphasized that dengue fever vaccine is an important tool in disease control. However, relying on the vaccine alone is not enough, because Aedes mosquitoes and viruses can still survive and maintain the risk of spreading. Therefore, vaccination needs to be combined with traditional measures such as mosquito control and larvae removal to ensure long-term and sustainable prevention.

The World Health Organization (WHO) also recommends that vaccination should be integrated into an overall disease control strategy, including vector control, case management, public awareness raising and encouraging active participation of people in disease prevention.

It is forecasted that by 2025, dengue fever and other infectious diseases will continue to develop complicatedly and become a major challenge for global health. Therefore, the synchronous combination of prevention measures will help reduce the spread of the disease, while ensuring the effectiveness and sustainability of dengue fever prevention.

Doctor Bach Thi Chinh, Medical Director of VNVC Vaccination System, said that dengue fever has unpredictable and complicated developments and can occur in both children and adults, in which the subjects with a higher risk of becoming more severe are children, pregnant women, people with chronic diseases, obesity, etc.

If not treated promptly, patients may experience dangerous complications due to dengue fever such as hypotension, heart failure, kidney failure, hemorrhagic shock, multiple organ failure, cerebral hemorrhage, coma, etc.

In pregnant women, dengue fever can cause fetal distress, premature birth, and stillbirth. The mother may experience uncontrollable bleeding, preeclampsia, liver and kidney damage, and prolonged bleeding during labor, which can be life-threatening.

Providing more information about the epidemic, Associate Professor, Dr. Tran Dac Phu, former Director of the Department of Preventive Medicine (Ministry of Health) said that Vietnam is currently circulating all 4 serotypes of the Dengue virus that cause dengue fever, in which the main circulating virus types are DEN-1 and DEN-2. The DEN-2 type is often associated with severe cases of dengue fever and epidemics. This is also the major cause of deaths related to the disease.

According to Associate Professor, Dr. Tran Dac Phu, thanks to vaccines, many dangerous diseases have been eliminated and cases have been reduced by hundreds, thousands of times such as smallpox, neonatal tetanus, polio, most recently Covid-19, and now dengue fever.

“The vaccine is a great achievement and will contribute effectively to the work of controlling the epidemic. The use of the vaccine will reduce the number of cases, severe cases and deaths,” Associate Professor, Dr. Tran Dac Phu assessed.

It is known that Takeda's dengue fever vaccine is currently approved by the Ministry of Health for use in Vietnam in May 2024, for children aged 4 years and older and adults.

The vaccine is effective in preventing all four types of dengue virus that cause the disease (DEN-1, DEN-2, DEN-3, DEN-4) with an effectiveness of up to 80% and prevents the risk of hospitalization by up to 90%. In particular, the vaccine is effective in preventing reinfection in people who have had dengue fever.

Source: https://baodautu.vn/canh-bao-nguy-co-sot-xuat-huyet-bung-phat-trai-mua-d256558.html