Kerstin Fritzl, one of seven children whom authorities say Josef Fritzl has confessed to fathering with his daughter, was brought to a hospital on April 19 unconscious and suffering from an unidentified infection.
She later suffered seizures. In addition to the induced coma, she was placed on a respirator and underwent dialysis because of the effects of lack of oxygen.
The 19-year-old woman "has been awakened from the induced coma and was able to leave the intensive care unit several days ago," said a statement e-mailed to The Associated Press by the central office grouping publicly run hospitals in Lower Austria province.
"The patient continues to need intensive medical ... and therapeutic care," said the statement, e-mailed by hospital spokesman Klaus Schwertner. It gave no timeframe for further treatment and offered no details as to where the patient now was.
Josef Fritzl is accused of raping his daughter repeatedly while confining her to a basement hideaway for 24 years.
Kerstin's hospitalization led to the unraveling of the elaborate crime when doctors appealed on TV for her mother to come forward because they needed information about the young woman's medical history.
Fritzl then accompanied his daughter, 42-year-old Elisabeth, to the hospital on April 26 and her story came to light shortly after.
On Friday, authorities decided to extend pretrial custody for Fritzl, 73, by another two months. Fritzl was formally placed in custody April 29 and will likely be charged when the investigation is complete.
Three of the children fathered by Fritzl, including Kerstin, were raised in a cellar at his home in the lower Austrian town of Amstetten, west of Vienna. Three others were brought up above ground to live with Fritzl and his wife, and one died in infancy. DNA tests confirmed Fritzl is the biological father of the six surviving children.
Schooling began for the children kept in the cellar last month. Christoph Herbst, a lawyer representing the victims, said then that the family was "doing well" but was expected to remain in the clinic for several months.