Many parents are opting out of the triple MMR vaccine

Two weeks ago, parents of 295 children who were given vaccinations at the Elstree Aero-Medical Centre were told to contact their doctor because the vaccines were thought to be ineffective.

Families were told the single shot immunisations given to toddlers between June and December last year were not done properly.

They were also told the vaccines themselves may have become contaminated, leading to an increased risk of the children suffering bacterial infections.

Lifeline Care, which runs the Hertfordshire clinic and another in Sheffield, has been ordered by the National Care Standards Commission to stop practising from the centres.

The clinics are not licensed and are operating outside the law.

Normal procedure

Following controversy over suggested links between the three-in-one MMR injection offered by the NHS, and autism, the parents had paid the clinics for single injections of the vaccines instead.

The problem arose because the clinics changed the normal procedure for making up the vaccines, according to the local NHS trust in Hertfordshire.

They began preparing batches of vaccines ahead of time, so more children could be treated - which investigators think may have led to the vaccines not working properly by the time they were administered.