Aoife Murray, from Ashfield, Mullingar, was on a trip to Medjugorje when she fell ill. It is understood the teenager is being treated for suspected meningitis.
The 15-year-old had travelled to Bosnia with her mother but was taken ill a number of days ago. She was taken to Mostar Hospital for treatment.
Her local parish priest Fr Barry Condron had hit out at the treatment the teenager had been receiving and called on hospital officials to allow her to travel back to Ireland.
A VHI spokeswoman said the health insurer had been in contact with the hospital in an effort to ensure the best treatment.
“The VHI assist team are in contact with the member and her mother with regard to her treatment,” the spokeswoman said.
In June 1981, the Virgin Mary is said to have begun appearing to a group of children.
The Catholic Church has not officially approved of the site, in the way it has approved of Lourdes or Fatima.
However, many millions of pilgrims, of all religions or of no religion, have visited Medjugorje, many even coming during the war years.