PHILIP Delaney was a vulnerable six-month-old baby when he was first injected with the unauthorised 'five-in-one' vaccine.
Over the next two months, he was given the combined jab on three separate occasions in an apparently secret trial.
Now, more than 40 years later, he is determined to know why he was given the jab in 1965 at the Bessborough mother and baby home in Co Cork.
Throughout the 1960s and 1970s three separate vaccine trials were conducted on Irish children on behalf of the multinational drugs company The Wellcome Foundation, which is now known as GlaxoSmithKline.
A report drawn up by the Department of Health in 2000, by its then chief medical officer Dr James Kiely, confirmed the existence of these trials.
It found 211 children were administered vaccines -- 123 of whom were resident in children's homes in Dublin, Cork and the midlands.
But unlike these victims, Philip has never been able to find out why he was given a vaccine that was never provided to the rest of the public. And, crucially, if it was part of a larger vaccine trial involving children in Bessborough.
Born John Martin to Margaret Finnegan on March 30, 1965, in Bessborough, he was given a routine BCG vaccine -- like every other child in the nation. But that was where the comparisons stopped.
In a sinister twist, he received an unknown 'five-in-one' vaccine which had an unprecedented mixture of polio, measles, diphtheria, whooping cough and tetanus.
And unknown to Philip it would never be used on the general public again.
According to records Philip obtained from the adoption agency Cunamh, he was given the experimental vaccine on three occasions. But his birth mother Margaret insisted she had no knowledge this mixture was being administered to him.
Margaret lived and cared for Philip at the home until he was adopted. "I was shocked when I heard he had received the vaccine. We were never told anything about any sort of vaccine," she told the Irish Independent.
"I am angry he was given the injection without my consent. The consequences could have been more serious," she said.
She became pregnant with Philip while working in Wales and was referred to the Cunamh agency in February 1965 at the age of 21. Fearing her parents would react badly to the news of her pregnancy, she gave him up for adoption.
Vera and John Delaney, from Walkinstown, Co Dublin, were delighted when the toddler was handed to them. They named the little boy Philip. But just a few days later, Mrs Delaney was stunned when a doctor arrived at her door to administer the final tranche of the vaccine.
Despite the four decades that have since passed, Mrs Delaney, who went on to adopt four other children, said she remembers the day clearly.
"The doctor came out and said she was giving him a five-in-one injection and that it would cover everything. I had never heard of that injection, but he was our first baby so we didn't really know what to expect.
"She said she would be back in a couple of weeks to take blood to check if the injection had taken."
This is confirmed by Philip's records, which show social worker Anne O'Donoghue noted the doctor had called and that she was due again in May.
"She called but before she left she said Philip should never have been sent for adoption, saying that he was one of 20 children trying out this new vaccine. She was angry and saying she had to go all over the country to look for these children."
Frightened by the encounter, Mrs Delaney was afraid the doctor would stop her from adopting Philip, but the order was finally made official on May 4, 1966.
But the thought still niggled the new mother and she brought Philip to her local clinic to ensure he was protected from all disease.
"I mentioned the five-in-one vaccine and they thought I was mad. They just gave him an oral polio vaccine and nothing for measles," she said.
A few months later Philip was struck down with measles.
"He got it quite bad and was very sick at the time. He also got very bad asthma in later life and I don't know if this was to do with the vaccine," she said.
For Philip, the knowledge that he had received the vaccine only came after he obtained his medical files some months ago.
He is still in shock, but now wants answers as to why it happened. He insisted he has not ruled out going down the legal route to bring whoever administered the experimental vaccine to justice.
"I want to get answers. I want to know why I was given this vaccine and who gave it to me," he said.