The five are now being treated with anti-AIDS drugs, said the official at National Taiwan University Hospital in Taipei.
The official spoke on condition of anonymity because she is not authorized to deal with the media.
In a posting on its website over the weekend, the hospital said the mistake occurred because a transplant staffer believed he heard the English word "non-reactive" on the donor's standard HIV test, which means negative, while the word "reactive" was actually given.
The hospital added that the information on the test result was given over the telephone and was not double-checked, as required by standard operating procedures.
"We deeply apologize for the mistake," the hospital said.
Shih Chung-liang, a Health Department official, said a department team will look into the mistaken transplants and decide on possible penalties for NTUH. If negligence was found to have caused the blunder, Shih said the hospital may have to suspend its transplant programs for up to a year in addition to unspecified fines.
The donor was a 37-year-old man who fell into a coma on Aug. 24 and his heart, liver, lungs and two kidneys were transplanted to five patients on the same day. The heart transplant was conducted at another hospital, while the four other transplants were conducted at NTUH, according to NTUH.
The donor's mother, who was not identified, told cable news stations that she felt terrible about the transplants and had not been aware of her son's ailment. She said he died after "falling from a high spot," without providing details.
Yao Ke-wu, who heads the health department of Hsinchu city, where the donor resided, decried the NTUH transplants as "appalling negligence."
He said NTUH staffers could have avoided the mistake by asking his department about the donor's medical history in advance, and deplored that such inquiries were not mandatory in Taiwan.
Yao said the five organ receivers will very likely contract HIV, and their anti-AIDS treatment will be further complicated because they also have to take medication to modify rejection of the new organs.
The five recipients are all Taiwanese. NTUH is among about a dozen well-equipped and highly-respected Taiwanese hospitals offering organ transplants.
There are also concerns among the physicians and nurses who conducted the transplants that they too may contract HIV. Medical staffers routinely take protections against bodily fluids during surgeries, but some experts also warned needle and other accidential cuts could still expose them to HIV.
Lee Nan-yao, a physician with the National Chengkung University Hospital, which performed the heart transplant, told the United Daily News that some physicians and nurses who had conducted the transplant "were depressed, and on the verge of panic."
Annie Huang, The Associated Press