Vaccine trials on children in institutions may have been more widespread than the three trials in the early 1960s and early 1970s publicly confirmed to date.
Initial investigations by an abandoned inquiry that took place just over a decade ago were already raising some questions about the issues of consent, regulation and the overall justification for these trials.
Well over 500 people indicated or suspected that they may have been subjected to experimental vaccine trials in children's institutions, a report from this previous investigation has shown.
While, since the investigation was abandoned, the report does not come to any definitive conclusions about the three trials or give us any definitive information about other trials, it does shed some light on the controversy.
It also gives us an inkling of how a revived statutory inquiry into this issue might progress. The Government has now announced that the vaccine trials issue is likely to be included in the new Commission of Inquiry into mother and infant homes.
In terms of the vaccine trials confirmed to have taken place to date, or any other trials as yet unconfirmed, questions are again being debated about their appropriateness and the procedures and processes surrounding them.
Public awareness of this issue has perhaps been sharpened by the legacy of a number of medical treatment and intervention controversies that have been well-documented in recent years.
In 2001, the Laffoy/Ryan Commission on child abuse, at the request of the Government of the day, set up a distinct division to look at child vaccine trials, after a report by the Department of Health into three trials carried out in the early 1960s and early 1970s made largely inconclusive findings.
Trial one tested a four-in-one vaccine for diphtheria, whooping cough, tetanus and polio; trial two tested an intra-nasal rubella vaccine, while trial three tested a three-in-one (diphtheria, tetanus, polio) vaccine.
The Department report had concluded that the decision to perform such trials was acceptable given the diseases the vaccines sought to prevent, but there were questions about consent, the arrangements made with the homes for the conduct of the trials and adherence to the 1932 Therapeutic Substances Act.
This Vaccine Trials Division's investigation following on from the Department's inquiry was abandoned following a successful legal challenge in 2004 and the Government in 2006, having examined relevant court case judgements, decided that there should be no further investigation of the vaccine trials.
Until the Tuam mother and baby home story broke earlier this month, the State had shown no apparent inclination in recent years to return to the contentious issue of medical trials on institutionalised children.
According to a progress report from the Vaccine Trials Division in 2003, 520 people had at that stage indicated to the Commission that they may have been subjected to a clinical trial of a vaccine while in an institution.
This followed an advertisement in the print media in Ireland and the UK inviting anyone who believed he or she was involved in a vaccine trial to contact the division.
The findings from the initial investigations detailed in the report indicate that many children may have been involved in trials other than three publicly-known vaccine trials carried out mainly in children's homes in the early 1960s and early 1970s.
The Commission's official remit went beyond the three trials that took place in the early 1960s and early 1970s.
The Laffoy/Ryan Commission's 2003 report said its remit on the vaccine trials issue encompassed the three vaccine trials carried out in 1960-61, 1970 and 1973 as well as any trials of a vaccine to test its efficacy or to ascertain its side effects found by the investigation to have taken place between 1940 and 1987.
The 2003 Vaccines Division report from the Committee mentions that documentation it received from the pharmaceutical company, GlaxoSmithKline, whose predecessor company was involved in the three trials, 'disclosed a considerable amount of information in relation to other vaccine trials conducted in the State'.
However, it said: "No determination has been made as to whether those trials are within the ambit of the functions conferred on the Commission," according to the report.
According to the 2003 report, after people had got in touch with it following the advertisement, a questionnaire was sent out to them seeking more detailed information. The report stresses that as the respondents would have been infants or very young children at the time of any trials the completion of the questionnaire would not be an easy task.
A total of 877 members of the public sent in completed questionnaires to the vaccines Division of the Commission.
* 158 positively alleged they had been involved in a vaccine trial.
* 219 suspected they may have been involved in a trial.
* 143 both alleged and suspected that they were participants in a trial.
A further 357 people indicated they were not part of a trial, did not know whether they had been, or did not complete the relevant portion of the questionnaire.
In some cases, people submitted medical records to the Commission.
This left 520 people who, back in 2002, believed they had been part of a vaccine trial in an institution when they were young children
This is 309 more than the number known to have taken part in the three to date publicly revealed vaccine trials carried out in the early 1960s and early 1970s. However, the inquiry did not get a chance to investigate any further the issue of other trials and only made preliminary progress on the issue of the three known trials carried out largely in mother and baby homes.
During this time, the Division had gathered some information, including starting to identify institutions where the three 1960s and 1970s trials were carried out and to match names of people who were likely to have been trial subjects to the institutions.
Investigations by the Division into 'trial one' that took place in five children's homes in 1960-61 had by 2003 ascertained the identities of all the trial participants except six children. Following a further media advertisement, the Division asked mothers and children resident in the five institutions in trial one to contact it.
While it had established the identity of mothers and children involved in trial one, for privacy and confidentiality reasons it decided it would not be appropriate to contact them directly, and instead decided to ask any trial subjects and mothers to come forward if they wished.
Checking those who made contact following the advertisement against data it held, the Division was able to confirm that six people who made contact had been trial subjects for trial one. The advertisement also led to contacts from the birth mothers of two of the trial subjects.
By July 2003, the Division had held public hearings on trial one, while preliminary investigations had begun into trials two and three. As the process was abandoned shortly afterwards, the Division had not begun to investigate in detail any evidence about other vaccine trials carried out between 1940 and 1987.
At this stage of the process, the report says, areas of concern arising included the absence of documentation or information on the facilitation, organisation and administration of trial one and the absence of any documentation on consent allegedly given for children to participate in the trial.
The Division's deliberations were suspended in November 2003 and officially abandoned the following year following a successful legal challenge by one of the doctors involved in the trials, Prof Irene Hillary, who had expressed concern that the attachment of the vaccine trial issue to the work of a commission into child abuse had implications for her professional reputation.
Essentially, the legal challenge succeeded as the doctor's claim that it was grossly unfair to attach the vaccine trial issue to the overall institutional abuse issue was upheld by the courts.
In 2012, it was announced that that the records collected by the Vaccine Trials Division while it was in operation were being dismantled, and this included returning the records to the original sources.
As for any new investigation into the controversial vaccine trials, its remit, if it is not stymied by legal issues, can be summed up in the words of former Health Minister Michael Martin in 2000.
He was commenting following the publication of the initial inconclusive Department of Health report on the three known trials in 2000. The then Minister asked:
* Why did children in care receive experimental vaccines?
* Why were some of the recipients outside the normal age for the administration of vaccines?
* Was the end result for commercial gain or public good?
* Why were the records of the trials so inadequate?
And furthermore, perhaps, the new inquiry may seek to examine the extent of other vaccine trials on children in care, and the circumstances under which they were conducted.
Discussions on this topic are now closed.