Carl Williams, Headteacher at Moreton School in Wolverhampton, has described an incident in which 20 pupils were jabbed with a diabetic testing needle as "frightening".
Some of the children have been taken to hospital for hepatitis jabs as a precaution.
An 11-year-old boy has been arrested.
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The British manufacturing giant - which is worth £13bn - is to make voluntary payments to settle cases across the world.
Sean Williams died after being struck by a car after he ran across two lanes of traffic while the lights were on green.
The accident happened on the A46 in Drayton, near to Wildmoor Spa, at around 12.30pm.