MORE than 150 children have been given an out of date polio vaccine.

Pharmacy staff alerted health bosses after the drops were given to 14- year-old pupils by a doctor.

Health bosses have launched an investigation to find out why no one noticed earlier that the vaccine was past its use- by date.

Now pupils at Inveralmond Community High School in Livingston, West Lothian, will have to take a second dose.

One parent said: "Its surprising the doctor made such a basic error. Our kids aren't looking forward to it because the drops taste absolutely vile and make them feel sick."

Health bosses insist that Inveralmond is the only school affected by the mistake.

Peter Gabbitas, chief executive of West Lothian Healthcare NHS Trust said: "The Trust has initiated an immediate investigation into how the time- expired drugs were issued. Appropriate action has already been taken to prevent any re- occurrence.

"We're making arrangements to re-immunise the children as soon as possible.

"The Trust would like to apologise to the parents and children at the school for any distress caused."

A West Lothian council spokeswoman said: "We have been reassured that there is no risk to the children who were given this vaccine.

"Our main priority is always the well-being of our students."