Mosquitoes in Vietnam: dengue, malaria and how to protect yourself
Vietnam has mosquitoes all year, and the main risk is dengue — 2026 cases are above normal. When they bite, which repellent to take, symptoms and when to see a doctor, malaria in Nha Trang and Da Nang, vaccines.
Short answer: there are mosquitoes in Vietnam all year, and the main risk is dengue fever. It's spread by Aedes mosquitoes, which bite during the day — most often in the morning and late afternoon. There's no malaria in Nha Trang, Da Nang or Ho Chi Minh City. Protection is simple: repellent with DEET, picaridin or IR3535, covering clothes, and air conditioning or screens on windows. See a doctor if you get a high fever after bites, and go straight to hospital with severe abdominal pain, vomiting or bleeding.
Is there dengue in Vietnam?
Yes, all year round — according to the CDC (updated 10 November 2026) and the UK's TravelHealthPro. Cases in 2026 are well above normal: more than 50,000 in the first five months, 2.5 times as many as a year earlier (Tuổi Trẻ and SGGP, 11 June 2026). Doctors say outbreaks no longer follow the old seasonal pattern: in late 2025 cases didn't fall as they used to. In Khanh Hoa province, home to Nha Trang, there were more than 5,900 cases and two deaths by early September 2025, with hotspots including Nha Trang (Tuổi Trẻ and SGGP, 12 September 2025).
When do dengue mosquitoes bite?
During the day. Dengue is spread by Aedes mosquitoes, which the WHO says are active in daylight; the CDC adds that bites peak early in the morning and late in the afternoon. So you need repellent in the daytime too — in cafés, on walks, by the water. Mosquitoes are most common in towns and suburbs (TravelHealthPro).
How to protect yourself from mosquitoes in Vietnam?
| What | How | Source |
|---|---|---|
| Repellent | DEET, picaridin (icaridin) or IR3535 | CDC, WHO |
| Clothing | long sleeves and trousers, especially morning and evening | CDC, WHO |
| Accommodation | air conditioning or screens on windows and doors | CDC, WHO |
| Water around the home | empty standing water: buckets, plant saucers, lids | WHO, CDC |
If you're renting long-term, ask the landlord about window screens before you move in — it's easier than fighting mosquitoes later. On accommodation — renting in Nha Trang.
What are the symptoms of dengue and when to see a doctor?
Symptoms start 4–10 days after a bite and last 2–7 days: high fever, severe headache, pain behind the eyes, muscle and joint aches, nausea, rash. Many people have mild illness or no symptoms at all. Warning signs can appear once the fever has dropped: severe abdominal pain, persistent vomiting, bleeding gums or nose, pale cold skin, lethargy. With any of these, go to hospital at once (WHO, CDC). There's no medicine that prevents dengue; treatment is up to a doctor. Where to go — hospitals in Nha Trang and if you fall ill in Nha Trang.
Is there a dengue vaccine?
It isn't recommended for ordinary travellers, according to the CDC and the WHO. The UK's TravelHealthPro says it may be considered for people who have had dengue before, and for others only after seeing a travel health specialist. Decide with your doctor before the trip. Which vaccines are advised for Vietnam — vaccinations for Vietnam.
Is there malaria in Vietnam?
Not in the cities of Nha Trang, Da Nang or Ho Chi Minh City (CDC, TravelHealthPro). Malaria occurs in rural areas, mainly in the south and the Central Highlands, and according to the CDC also in rural Khanh Hoa province outside Nha Trang. If you're only visiting cities and resorts, antimalarial tablets usually aren't needed; if you're heading into jungle or mountains, ask a doctor.
What other diseases do mosquitoes carry in Vietnam?
Japanese encephalitis — nationwide, all year, peaking May to October. The CDC and TravelHealthPro advise the vaccine for people living in Vietnam or spending a month or more in risk areas — which includes winter stayers. Chikungunya and Zika also occur; pregnant women should discuss the trip with a doctor in advance (CDC, TravelHealthPro). The same thing protects against all of them — not getting bitten.
FAQ
Are there many mosquitoes in Vietnam? Mosquitoes are around all year, most of all in towns and near water. Indoors with air conditioning and screens there are hardly any.
Are mosquitoes in Vietnam dangerous? The main risk is dengue: it's present all year, and 2026 cases are above normal.
When do dengue mosquitoes bite? In the daytime, most often morning and late afternoon.
Which repellent should I take? One with DEET, picaridin or IR3535 — recommended by the CDC and WHO.
Is there malaria in Nha Trang? No. Malaria is found in rural areas, not in cities or resorts.
Do I need a dengue vaccine? It isn't recommended for ordinary travellers; decide with your doctor.
What should I do with a high fever? See a doctor. Severe abdominal pain, vomiting or bleeding — go to hospital at once.
Sources and checks
Dengue risk, malaria, Japanese encephalitis, chikungunya, Zika — CDC Travelers' Health (updated 10 November 2026) and TravelHealthPro. Vector, symptoms, warning signs, protection — WHO (dengue fact sheet, 21 August 2025) and CDC Yellow Book 2026. Cases in Vietnam — Tuổi Trẻ and SGGP (11 June 2026), Vietnamnet (7 November 2026); Khanh Hoa — Tuổi Trẻ and SGGP (12 September 2025). Checked 12 November 2026. This isn't medical advice: decide on vaccines and treatment with a doctor.