Health and vaccines for a Mekong River trip

Which vaccines for Laos, Cambodia and Vietnam?

No vaccine is required for travelers arriving from the United States. A yellow fever vaccination certificate is only required in Cambodia and Thailand if you arrive from a country with a risk of yellow fever^[2][4].

For all four countries, the CDC recommends being up to date on routine vaccines and getting the hepatitis A vaccine. It also recommends hepatitis B for unvaccinated travelers younger than 60 (all unvaccinated travelers for Vietnam), typhoid for most travelers, Japanese encephalitis for stays of a month or more or for rural activities, and suggests considering rabies depending on your activities^[1][2][3][4]. In Laos, adults should also get a polio booster^[1]. See a travel health provider a few weeks before you leave.

Japanese encephalitis transmission peaks from May to October in Cambodia, Thailand and Vietnam, and from June to September in Laos; the risk is extremely low for most travelers and higher for long rural stays during the peak^[5].

Malaria along the Mekong: where you need preventive medication

In Laos, the provinces where the CDC recommends preventive medication include Thakhek, Savannakhet, Pakse and the 4,000 Islands, all major stops on the river^[1]. Everywhere, bite prevention remains the rule. Any fever during your trip or in the months after you return requires prompt medical care; tell the doctor where you traveled.

Dengue in 2026: an epidemic year in Cambodia

Cambodia had recorded 68,951 dengue cases and 87 deaths by August 23, 2026, nearly twice as many as at the same date in 2025; the peak seemed to have passed by late August^[6]. Dengue was declining in Laos: 3,574 cases by August 8, 42% fewer than a year earlier according to the WHO^[7], and 4,371 cases by August 24 according to the official Lao news agency^[8]. In Vietnam, cases were up 41.5% from January to August, rising in Ho Chi Minh City in late August^[9]. The CDC has a Level 1 dengue notice for Cambodia and Vietnam^[2][3]: protection against mosquito bites, day and night, is the main defense.

Can you swim in the Mekong? Schistosomiasis near the 4,000 Islands and Kratie

A form of schistosomiasis specific to the Mekong, spread by small freshwater snails, persists in two areas along the route: southern Champasak province, in the 4,000 Islands (Khong district) and neighboring Mounlapamok district^[10], and the Cambodian provinces of Kratie and Stung Treng^[11]. Both countries aim to eliminate it, Cambodia by 2030^[11]. The CDC advises against swimming in unchlorinated lakes and rivers in Laos and Cambodia^[1][2].

Raw fish and liver flukes

The liver fluke Opisthorchis viverrini is found in Laos, Cambodia, Vietnam and Thailand. People catch it by eating raw, undercooked or fermented freshwater fish; chronic infection is strongly linked to bile duct cancer. Prevention is simple: fish that is thoroughly cooked, or frozen^[12]. In riverside villages, skip raw or fermented river fish dishes.

Getting medical care along the Mekong: hospitals and emergency numbers

In Laos, no major care is available: the French government advises seeking evacuation to Thailand in any emergency^[13]. According to the Australian Embassy, most patients are referred to Aek Udon hospital in Udon Thani, two hours from Vientiane, and there are hospitals in Nong Khai, 45 minutes away^[14]. In Thailand, all hospitals require a guarantee of payment before treatment^[15]. Medicare does not cover care abroad: see our travel insurance guide.

Pierre-Marie Coupry

Editor-in-chief of the French travel site Bon Plan Voyage, where he has published since 2012. He checks every practical detail against official sources and proofreads everything before it goes live.

Our method