
The fifth victim, a 15-year-old girl of Chon Buri province, became the youngest victim.
Doctors said The student had chronic illness including brain tumor and diabetes.
Earlier the ministry revealed that the fourth victim was a 47-year-old man who was a heavy smoker and drinker.
Rajvethee Hospital director Dr Warunee Jinarat said the succumbed to heart and kidney failure at her hospital on Wednesday.
Warunee refused to give further detail about the man, saying only he was a cleaner and was exhausted by overwork and not enough rest.
A Thai navy cadet died of H1N1-related symptoms Monday. A 40-year-old woman died on June 22 and a 42-year-old man died Saturday of H1N1-related complications.
The ministry on Wednesday announced 59 new flu cases in Thailand, bringing the total in the kingdom to 1,473.