08:50 - 06 March 2007 A Schoolgirl from the north-east is at the centre of a legal battle to prove that her deafness is linked to a form of the controversial MMR triple vaccine.
Katie Stephen, 16, became ill and suffered a severe fever just 10 days after she was administered an early form of the vaccine as a toddler in 1991.
The Aberdeenshire youngster lost the hearing in her left ear following the alleged reaction, which showed similarities to the brain disease encephalitis.
Katie's parents, Wendy and Alistair, of Carron Terrace, Stonehaven, joined a group litigation against the drug companies that manufactured the particular vaccine, which included the Urabe strain of mumps and was first used on children in 1988.
A bad reaction can involve swelling of the brain, the lining of the brain or the spinal cord, which can lead to brain damage, deafness or death.
Yesterday, the family's fight became more determined after documents released under freedom-of-information legislation indicated that the UK Government had been aware of the health risks associated with the vaccine but continued to use it.
The vaccine was blamed for the deaths of several children after eventually being withdrawn by the Department of Health in 1992.
More recent forms of the vaccine have been at the centre of a separate row over alleged links to autism, prompting some parents to refuse to allow it to be administered to their children.
Katie, a fifth-year pupil at Mackie Academy at Stonehaven, became aware of her parents' fight to prove a link to the vaccine only as she neared the end of primary school.
She spoke yesterday for the first time about the battle she and her family have gone through and about how she has learned to live with her partial deafness.
"It's always been there but it's become more a part of my life as I grow up," she said.
"When I thought about going to high school, I began to worry and it started to dawn on me how it would affect me."
Doctors said the nerve between her brain and left ear was "totally shot" and could not be repaired.
This has left her unable to cope with noisy situations and she becomes disorientated in busy public places.
Katie said: "When there's background noise I can't pick out individual sounds or what people are saying. It makes it harder for me to be involved in discussions.
"I have a group of friends who make it easier for me and help me understand but when I'm out shopping I get lost in the noise.
"It can get quite awkward. People don't like it when I ask them to repeat something."
Despite the lifelong affliction, she is determined to pursue a career in musical theatre and has contacted a union that helps disabled people.
She said her initial feelings of coming to terms with her partial deafness are turning to anger as the lengthy legal challenge steps up.
"I feel quite angry when I think about it," Katie said. "It shouldn't have happened to me.
"But also I think about the amount of effort my mum's put into this, going to London because of court dates. It shouldn't have happened to her either."
Her 49-year-old mother is due back in court this month as the MMR litigation inches forward another step in the case against drug company Smith Kline and French Laboratories, as it was known at the time.
Mrs Stephen said she had considered giving up the fight but vowed to continue for the sake of her daughter and other affected families.
She said: "This should not have happened to my daughter. I used to try and tell her it was just an accident but now I don't.
"It can't happen to anyone now - the vaccine is different - but it was quite obvious to me what happened then.
"She was a healthy baby. She was given the injection and 10 days later was seriously ill."
Katie's older sister, Emma, 25, was given earlier individual injections and suffers no hearing problems. Younger sister Anna, 10, was not given any injection against mumps, measles or rubella.
More than 2,000 parents, the vast majority from England, have joined the MMR litigation since around 1997.
Many children of families alleging links with the strain have severe physical disabilities and in some cases they use wheelchairs.
