As the measles outbreak in Wales continues the false claims of a doctor 15-years-ago over the MMR vaccine have been blamed for the spread of the disease.
But despite the link being debunked in 2010 Karenza Cassidy remains convinced that the MMR vaccine led to her son's autism and consequently has not had her youngest child immunised.
Ms Cassidy claims that she witnessed the effects of autism on her third son Eddie in the wake of the MMR.
To me it's very clear because it literally happened in front of me.
I've since read research obviously on both sides of the argument but really that's quite separate from the issue when you see something happening like that.
Eddie was 15-months-old when he had the MMR and was diagnosed with autism when he was two.
He is considered 'severely autistic' on the autism spectrum.
Because of her fears she stopped her youngest child Maddison, who is now 12, having the MMR jab. Both of her eldest children were vaccinated before Eddie and have not developed autism.
When I'm living day-to-day with what I'm seeing as an adverse reaction to MMR, if I had to choose I can honestly say that between one of my children getting the measles and one of them getting autism - I would go for measles any day of the week.
The claims that link MMR and autism have been widely discredited and Public Health Wales recommends parents have their children vaccinated with the MMR.
– Public Health Wales spokesperson
Although there was publicity in 1998 on a report claiming a link between the MMR and autism, numerous studies undertaken to investigate the claim have found no such link.
Our advice is unequivocal, the MMR vaccine is recommended by the World Health Organization, UK Department of Health and Public Health Wales as the most effective and safe way to protect children against measles.
Background to the MMR 'scare'
Research published by the Dr Andrew Wakefield in 1998 suggested a link between the triple vaccine for measles, mumps and rubella and autism.
Published in the respected Lancet medical journal, the report received widespread media attention and lead to a significant decline in children being given the MMR vaccine.
But concerns were raised when other scientists failed to recreate his results and the General Medical Council launched a review of the research.
The Sunday Times journalist Brian Deer exposed significant flaws in Dr Wakefield's research and ethical practices.
Following an extensive investigation in 2010, the General Medical Council struck Dr Wakefield off the medical register, describing him as "dishonest", "unethical" and "callous".