Only 12 of 32 potentially infectious HIV donations have been traced by the Irish Blood Transfusion Service, the tribunal heard yesterday.
All but one of the 12 tested negative, the exception being the donation which infected a Co Kilkenny nurse in July 1985 with HIV.
Dr Emer Lawlor, the IBTS's deputy medical director, said it was possible up to six other donations were infectious and that the recipients had since died but, due to a lack of adequate documentation, one will never know.
She stressed, however, it was "most unlikely" anyone was "walking around" unaware they had been infected with HIV.
Dr Lawlor was being questioned on a look-back programme initiated by the agency in September 1996 to see what happened to the prior, untested donations of donors who were found to be positive for HIV after testing was introduced in October 1985.
Of 15 "low risk" donations from before 1980, only five were traced. Of 11 "high risk" donations from 1981-1982, four were traced. And of six "highest risk" donations from 1983-1985, three were traced.
One of these was a donation on July 16th 1985, from the HIV-positive Donor A, which infected the Kilkenny nurse through a blood transfusion.
Dr Lawlor agreed the destruction of all pre-1986 BTSB dispatch records in 1993 made the look-back "infinitely more difficult". The tribunal has heard the records were destroyed while in the care of the former senior technical officer, Mr Sean Hanratty, in contravention of a order by ex-CEO Mr Ted Keyes.
Dr Lawlor further agreed if the look-back had been done earlier the number of infections discovered would be likely to have been higher. "I think the six (highest-risk cases) would be the maximum" but "we don't know".
She added it was "very unusual" for anyone to show up as late as the Kilkenny nurse, who discovered she was HIV-positive independently of the board in December 1996.
Dr Lawlor later reiterated the look-back should have begun in at least July 1987 when Dr Terry Walsh, a former senior haematologist with the board, drew up a list of potentially infectious donations, which included Donor A's July 1985 donation. She said the list had been stored in a manila folder in a fireproof safe in Pelican House and was found only in 1996.
Asked who would have had access to it in the meantime, Dr Lawlor replied she presumed Dr Walsh, Dr Vincent Barry, the former chief medical officer, and Mr Keyes.
She agreed withholding the information between 1987 and 1996 would have been "unconscionable". However, she said she did not know whether it was done deliberately.
Under cross-examination by Mr James Connolly SC, counsel for the Kilkenny health worker, Dr Lawlor denied a leaflet on AIDS introduced by the BTSB in July 1983 was a "token" screening process.
