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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Remaining very windy with gales. Rain soon clearing, with sunny intervals developing.
Outbreaks of rain, sometimes heavy, will soon clear. Sunshine and scattered showers will follow. Mainly dry later.
Localised gales will develop across parts of the region tonight. Tomorrow there will be sunshine and scattered showers.