A leading liver specialist has said that women who received suspect batches of anti-D should be recalled for testing.
The Blood Transfusion Service Board (BTSB) is aware of up to 19,000 women who received potentially infectious product but tested negative for the hepatitis C virus.
Dr Aiden McCormick, a consultant hepatologist at St Vincent's Hospital in Dublin, said that it would be "reasonable" to test the women more than once. "In any area of medicine, where there is a high reason to suspect a person has been exposed to a virus, it is sensible to retest", he added.
Dr McCormick, who treats hepatitis C patients, emphasised that the chances of any of these women having the virus was "very small". He conceded that repeat testing would be upsetting for many of the women, who had already undergone testing in 1994.
Dr McCormick emphasised that he was not familiar with the work of the expert group which had been set up by the Department of Health to assess the situation relating to these women.
In a statement, the BTSB said that any decisions would be made on the basis of advice from the expert group. "The BTSB awaits the decisions of this expert group and will act on any recommendations made." The next meeting of the expert group is not due until early in September.
The statement said that the BTSB wished to re-emphasise that the continuing focus of the anti-D screening programme was directed at women who had never come forward for testing. "The BTSB wishes to further assure those women who have come forward and received a negative result that the risk of them being infected with hepatitis C is extremely remote."
The board urged women who have never had a hepatitis C test and who received anti-D between May 1997 and the end of 1978, or between March 1991 and February 1994, to come forward.
The statement continued: "The BTSB has conducted the most comprehensive testing programme ever mounted worldwide, through a major public awareness programme, including a national advertising campaign, accessing hospital and Department of Social Welfare records, liaising with general practitioners and direct written appeals."
To date, about 65,000 women have come forward and some 64,000 of these have tested negative. "Of this [number], approximately 19,000 women may have received potentially infectious product and subsequently tested negative for the virus."
There are three possible reasons, according to the BTSB, for the negative results:
the particular product the women received was not infected;
the recipient, for reasons which are not currently medically understood, did not become infected;
the recipient did become infected, but her immune system was able to combat and clear the virus.
Positive Action, which represents women infected with anti-D, has said that it also subscribes to the belief that there is a minimal risk to these women. However, its chairwoman, Ms Jane O'Brien, told The Irish Times that it was aware that more doses of infected and potentially infected anti-D had been administered than would account for the number of women who were identified in the national screening programme.
All the anti-D given to the 65,000 women who came forward for testing was made from plasma donated by two women, known as patient X and patient Y, who were both infected with the virus. Patient X's anti-D was administered in hospitals from May 1977 to the end of 1978; patient Y's anti-D was administered between March 1991 and February 1994.
While the BTSB has ascertained that the anti-D came from these two sources, it is not known if every vial was infected. Nor is the level of infection in each vial known. This may explain why some women became infected and others did not.