More than 120 pupils and staff at Wallingford School are facing an anxious week-long wait to see if they have contracted TB.

The move comes after a teenage boy at the school contracted the disease.

Oxfordshire's consultant on infectious diseases, Dr Dick Mayon-White, said there was no cause for alarm.

He said the screenings were purely a precaution.

Dr Mayon-White said: "I would be most surprised indeed if anyone else showed signs of the infection.

"But we have to take precautions and that is why the screening is being done."

The action on Tuesday came after a pupil was taken ill over Christmas. The teenage boy was taken to his GP where it was discovered that TB had been detected in other members of his family.

Public health experts waited until tests proved positive before telling other pupils and staff, and health screenings were organised.

Dr Mayon-White said: "All pupils in the same class and who use the same bus, and all staff who have had contact with the patient were tested.

"The results will be known next week."

He said the boy who contracted tuberculosis is responding well to treatment. TB is treated with drugs and no longer forces the patient into isolation.

Oxfordshire phased out the TB vaccination -- known as the BCG -- about three years ago in line with Government policy.

Dr Mayon-White said the county had 30 to 40 cases a year, which is a rise of a third in a decade.

He said they came mainly from people who had picked it up abroad or who had contracted it from inside the family. Others can get it from living rough and being homeless or getting it from contacts at work.

No-one at Wallingford School was prepared to comment.