Two people have died of heat stroke in Hanoi this month while a third is in a coma.
All three were taken to 108 Military Central Hospital and the comatose person is in critical condition, according to Dr Nguyen Thi Nga of the hospital.
They were manual laborers who had worked outdoors for several hours in the heat, which caused high fever, organ damage and cardiovascular failure.
The survivor was admitted last Saturday with the body temperature of 42 degrees Celsius (107.6 degrees Fahrenheit) and multiple organ failure. The 50-year-old woman’s temperature has returned to normal thanks to doctors’ efforts, but remains in a deep coma.
Nga cautioned people against going out during hot days, and remain well hydrated and fully covered if they must work outside to avoid heat strokes.
Northern and central Vietnam have going through a scorching summer. Temperatures in Hanoi peaked at 40 degrees Celsius last Saturday while temperatures in Hue in central Vietnam have been around 39 degrees.
Last month, a 50-year-old man who had been harvesting peanuts in a field in the central province of Ha Tinh collapsed and died of a heat stroke.
Meteorologists have warned that people should brace for more heatwaves this summer.
A study published in the journal Climatic Change last September said Southeast Asian nations like the Philippines and Vietnam would be most affected by heat-related mortality along with countries in southern Europe and South America.