[Coolhand]

Advice from NHS
Yellow fever: Although yellow fever does not occur in Thailand, an official yellow fever vaccination certificate may be required depending on your itinerary.
Requirement: A yellow fever vaccination certificate is required for travelers over 1 year of age coming from infected areas. A certificate is also required from travelers arriving from endemic countries.
Other vaccines: Depending on your itinerary, your personal risk factors, and the length of your visit, your health care provider may offer you vaccination against hepatitis A, hepatitis B, influenza, Japanese encephalitis, rabies, or typhoid. Routine immunizations, such as those that prevent tetanus/diphtheria or "childhood" diseases, should be reviewed and updated as needed.
Malaria:
Risk is limited to evening or nighttime exposure in rural forest/jungle areas infrequently visited by travelers: primarily international border regions with Laos in the north and east, with Myanmar in the west, and with Cambodia in the east. Risk is highest in the provinces of Chiang Mai, Mae Hong Son, Tak, Kanchanaburi, Ratchaburi, Chanthaburi, Trat, Prachuap Khiri Khan, Surat Thani, Sa Kaeo, and Yala. Risk is lower in most provinces of the southern isthmus. There is no risk in the interior of Thailand nor in the cities and main tourist resorts (Bangkok, Chiang Mai, Chiang Rai, gulf islands, Pattaya, Phuket Island, Ko Samui, etc.)
Take evening and nighttime insect precautions in risk areas. Medicines that protect against malaria in this area include doxycycline or atovaquone/proguanil (Malarone). Primaquine may be used in special circumstances (G6PD testing is required). Because mefloquine resistance is reported from areas near the borders with Cambodia and Myanmar, mefloquine is not an option in Thailand. The best drug for you depends on your itinerary and on a number of personal factors that should be discussed between you and your health care provider.
Because no preventive measure is 100% effective, if you have traveled in an area of malaria risk, seek immediate medical attention for any fever or flu-like illness occurring within 3 months of your return home. Be sure to tell your health care provider your travel history.