St Vincent's Hospital in Dublin has admitted members of non-frontline staff have received the Covid-19 vaccine.
It comes amid reports that intensive care workers were among those who had to wait for the jab after a "glitch" in the booking system.
The situation has caused distress among frontliners who have been at patients' bedsides daily.
When asked on Monday if retired surgeons and private secretaries were given the vaccine above some nursing staff, a spokeswoman for the hospital said the priority list "follows national guidelines which is to provide the vaccine to groups of health care workers who are delivering direct patient care".
However, yesterday the spokeswoman acknowledged that "in certain instances non-frontline staff have received the vaccine to ensure that no vaccine is wasted". She said the earlier statement was "correct".
She added: "Our priority list has been in line with the guidelines to provide the vaccine to groups of health care workers who are delivering direct patient care.
"Following frontline staff, vaccination is provided to staff who in the course of their duties may be on wards or in direct contact with patients and staff, as well as other staff who in a surge may be redeployed to support frontline staff."