Da Nang's dengue count has more than doubled this year. Plan Hoi An around the daytime mosquito.
- CDC Level 1 Global dengue (Vietnam listed)
- Travel clinic CDC recommends medicine or vaccines for some areas · which ones
Da Nang's disease control center counted 4,251 dengue cases by October 1, 2026, 2.4 times the same point in 2025, with the central coast's rainy season still ahead. The CDC lists no malaria for Da Nang city, and the mosquito that matters bites in daylight around the Ancient Town, cafes and riverside tables.
Yes. The day-biting mosquito that spreads dengue lives around Hoi An's Ancient Town and Da Nang's beaches, and Da Nang's disease control center counted 4,251 dengue cases by October 1, 2026, 2.4 times the same point in 2025. The CDC lists no malaria for Da Nang city, so a town-and-beach trip comes down to a daytime repellent habit and some care along the river at dusk.
Da Nang's dengue year
Da Nang's Center for Disease Control reported 4,251 dengue cases as of October 1, 2026, 2.4 times as many as at the same point in 2025, and 283 outbreak sites, 3.9 times as many, according to Vietnamese press reports in early October. That is a steeper rise than the country's. Nationally, cases through September 20 were about 37% above 2025, with roughly 71% in the south, the World Health Organization reported. Vietnam is on the CDC's global dengue list. The figures cover Da Nang city, and Hoi An, just down the coast, shares its weather and its mosquito.
The Aedes mosquito bites in daylight, with peaks after sunrise and in the late afternoon, which line up with Ancient Town walks and riverside dinners. Put repellent on over sunscreen in the morning, again after swimming and again before sunset, and choose an air-conditioned or screened room. Our dengue & Zika routine has the full schedule. If you're pregnant, talk to a healthcare provider before the trip, because Zika has circulated in Vietnam.
Malaria and the countryside
The CDC places Vietnam's malaria in "Rural areas only; rare cases in the Mekong and Red River Deltas," and reports "None in the cities of Da Nang, Hai Phong, Hanoi, Ho Chi Minh City (Saigon), Nha Trang, and Quy Nhon." It doesn't name Hoi An, whose Ancient Town is urban.
If you're heading into the countryside. For "All other areas with malaria transmission (except Mekong and Red River Deltas)," the CDC lists "Atovaquone-proguanil, doxycycline, mefloquine, tafenoquine." It doesn't say whether Hoi An's rural outskirts, My Son or Ba Na Hills fall in a transmission area. If your plans include rural homestays or treks inland, book a travel clinic 4–6 weeks before departure and bring the route. The same visit can settle Japanese encephalitis vaccine, which the CDC suggests considering for shorter trips with rural stays and doesn't recommend for short city trips.
River, beach and hills
Hoi An's mosquitoes have a reputation for being manageable, with the worst along the Thu Bon river, at riverside resorts and on countryside bike rides. Cover your legs for riverside dinners, basket-boat trips and afternoon rides, and reapply before you set off. Ba Na Hills tends to be cooler, and a daytime visit likely means fewer bites. At An Bang, the stinging some swimmers feel is likely sea lice or jellyfish larvae rather than insects, so repellent is unlikely to help.
When to go
The central coast's rains come roughly October to December, often starting in September, and the Ancient Town often floods in October and November. The driest months, roughly February to May, are the easier stretch for bites. Da Nang's 2026 dengue was still climbing at the start of October as the rains began. During floods, stay out of the water, since the CDC's Vietnam page lists leptospirosis and melioidosis and advises avoiding floodwater.
Where you're going
Hoi An Ancient Town & the Thu Bon river
The Ancient Town is urban, and the CDC doesn't name Hoi An for malaria. The day-biting dengue mosquito is the one to cover for, and the worst bites tend to be along the river and at riverside resorts.
An Bang & Cua Dai beaches
Beaches where the complaints tend to be about stinging water rather than mosquitoes. Wear daytime repellent anyway for dengue, and reapply after swimming.
Marble Mountains & My Khe Beach
Inside Da Nang city, where the CDC reports no malaria. An urban beach strip and cave pagodas with the day-biting dengue mosquito, so repellent goes on before you leave the hotel.
Ba Na Hills & the Golden Bridge
A hilltop resort that tends to be cooler than the coast. The CDC's malaria wording doesn't address it, and a daytime visit likely means less exposure than a day by the river.
Continuing to Hanoi, Ha Long Bay or Saigon? The Vietnam briefing covers the rest of the route.
The Hoi An kit
- Picaridin 20% travel sprays: odorless in the heat and layers over sunscreen. One 3.4 oz bottle covers about a week of daily use for one person.
- A full-size backup in the checked bag. Daytime use for dengue goes through a bottle faster than evening-only spraying.
- Light long pants for riverside dinners and basket-boat trips.
What travelers report
Paraphrased from TripAdvisor threads and a review and linked so you can read them in full. None is dated, and bites vary with the season and how close you stay to the river.
- Hoi An
A poster who had just come from Siem Reap found Hoi An's mosquitoes mild by comparison. Another reply said the worst of them were along the river, near the riverside resorts. TripAdvisor ↗
- Hoi An
A traveler bitten in Hoi An worried about dengue. Replies said only one mosquito species carries it and the chance of infection from any one bite is low, but still advised repellent. TripAdvisor ↗
- An Bang Beach, Hoi An
A reviewer found the beach beautiful but the water stinging; a local blamed invisible jellyfish, and other posters suggested sea fleas. TripAdvisor ↗
One rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in Vietnam. Dengue usually shows up within two weeks of the bite. Already bitten and wondering how worried to be? Bitten in a dengue zone has the honest odds.
Traveler questions
Is dengue bad in Da Nang and Hoi An right now?
Da Nang's Center for Disease Control counted 4,251 dengue cases by October 1, 2026, 2.4 times the same point in 2025, Vietnamese press reported, and the central coast's rainy season was only starting. Vietnam is on the CDC's global dengue list. The figures cover Da Nang city, and the same routine applies in Hoi An: repellent from the morning on, again after swimming and again before sunset.
Do I need malaria pills for Hoi An?
The CDC reports no malaria in the city of Da Nang and places Vietnam's transmission in "Rural areas only." It doesn't name Hoi An, whose Ancient Town is urban. For rural areas outside the Mekong and Red River Deltas it lists atovaquone-proguanil, doxycycline, mefloquine and tafenoquine, and it doesn't say whether Hoi An's outskirts, My Son or Ba Na Hills count. If your plans go beyond the towns and beaches, ask a travel clinic 4–6 weeks before departure.
When is the best time to visit Hoi An for fewer mosquitoes?
Roughly February to May, the central coast's driest months. September to December brings the rains, the Ancient Town often floods in October and November, and in 2026 Da Nang's dengue was still climbing as the rains began. Dengue is reported in every month, so keep the daytime routine whenever you go.
Should I worry about the autumn floods?
Floodwater carries its own risks. The CDC's Vietnam page lists leptospirosis and melioidosis and advises avoiding floodwater, so stay out of flooded streets where you can. The pools left behind after the rains also give the dengue mosquito places to breed, so keep the repellent habit going after a storm.
Sources
Health authorities, surveillance reports and news coverage of official bulletins used for this briefing, last checked October 2026. Traveler reports are linked where they appear. This page summarizes public-health guidance and is not medical advice.