Anh Tuyet, residing in Phu Nhuan ward, TP HCM, is planning a one-month summer trip with her family to several Northern provinces. The trip includes visiting terraced fields, livestock farms, and staying in the countryside. Before the journey, she researched mosquito-borne illnesses and decided to get vaccinated against japanese encephalitis.

Tuyet shared that she had read about adults contracting japanese encephalitis, requiring prolonged treatment, and facing the risk of lasting neurological sequelae. What worried her more was that in its early stages, the disease may only manifest as fever and headache, easily mistaken for common viral infections.

"My family will travel through many areas with fields, trees, and livestock farms. I want to proactively prevent the disease before the trip for greater peace of mind", Tuyet said.

Anh Tuyet received the Imojev japanese encephalitis vaccine at VNVC Hoang Van Thu to prevent illness before her trip, which includes visiting her hometown. Photo: Dieu Thuan

Similarly, Thanh Hieu, 42, from Hiep Binh Chanh ward, TP HCM, also received the japanese encephalitis vaccine at VNVC Hiep Binh Chanh. As a civil engineer, he frequently works at construction sites in the Central and Western regions. Many of these sites are located near trees, fields, farms, or areas with standing water, making it difficult for him and his colleagues to avoid mosquito bites.

Hieu mentioned that he has two young children. His older child has been vaccinated against several mosquito-borne diseases as advised by their doctor, while his younger child is just over four months old. Since he frequently travels for work, he aims to reduce the risk of illness, especially during the rainy season.

"For any disease with a vaccine that is suitable for my family's age and risk, I consult the doctor to get myself and my children vaccinated", he said, adding that his wife also received the japanese encephalitis vaccine before her pregnancy.

According to Dr. Huynh Tran An Khuong, Medical Specialist at the VNVC Vaccination System, japanese encephalitis is an infectious disease caused by the japanese encephalitis virus. The virus is transmitted to humans through the bite of Culex mosquitoes. These mosquitoes become infected after biting hosts carrying the pathogen, primarily pigs and some species of water birds.

The disease is prevalent in many Asian countries, including Vietnam. While children are a primary focus group, adults without immunity or those not receiving scheduled booster shots remain at risk if exposed to infected mosquitoes.

In its early stages, patients may experience fever, headache, nausea, and fatigue. Some cases progress to severe encephalitis, leading to altered consciousness, seizures, and respiratory failure. The World Health Organization reports that the mortality rate in people with severe symptoms can be up to 30%; approximately 20-30% of survivors experience long-term neurological, cognitive, or behavioral sequelae.

Dr. Khuong stated that the risk of contracting the disease depends on the destination, length of stay, disease season, and outdoor activities. Individuals traveling, working, or living in rural areas, especially near rice fields, ponds, or livestock farms, particularly during the rainy season, should seek advice on disease prevention before their trip.

Culex mosquitoes bite hosts carrying the japanese encephalitis virus, primarily pigs and birds, then transmit the disease to humans through bites. Photo: Vecteezy

Currently, there is no specific treatment for japanese encephalitis. Treatment is primarily supportive and focuses on managing complications. Therefore, prevention through vaccination and avoiding mosquito bites plays a crucial role.

Vietnam offers japanese encephalitis vaccines for children and adults, including: Jevax (Vietnam), Jeev (India), and Imojev (Thailand). Doctors advise appropriate regimens based on vaccine type, age, vaccination history, and exposure risk. Individuals who previously received inactivated vaccines in earlier immunization programs need to ensure booster shots to maintain immunity. If booster schedules are difficult to adhere to, children and adults should visit a vaccination facility for advice on suitable vaccines to complete their immunization schedule.

In addition to vaccination, people should wear long-sleeved clothing, sleep under mosquito nets, maintain clean living areas, remove standing water, and protect livestock pens. If high fever, headache, vomiting, confusion, seizures, or other neurological signs appear, patients should seek medical attention early and avoid self-monitoring at home.

Phuc Long