Dominic is a pupil at Ysgol Penweddig

Eight days after his ordeal, Dominic Hamer, 13, is back to full fitness.

However, his father has appealed for an investigation into the drug, but said children must continue to be vaccinated.

He also paid tribute to staff at Bronglais Hospital who nursed his son.

Dominic, a pupil at Ysgol Gyfun Penweddig, spent a night in intensive care before being transferred to a general ward last week. He returned home, to Bow Street, near Aberystwyth, on Friday.

He was said to have had an anaphylactic shock, which is defined as a very sudden serious physical reaction caused by an allergy.

Two other pupils, who were also treated in hospital, were discharged last Wednesday.

There should be a more vigorous investigation into the BCG vaccine Paul Hamer

Another 10 students also received medical help at Bronglais after suffering "adverse effects" to the injections.

Nearly 120 pupils at the comprehensive school were being injected with the BCG vaccine, which combats tuberculosis.

Meanwhile, another Aberystwyth comprehensive school, Penglais, will begin its BCG vaccinations on 6 December.

The school has been assured by health officials that its pupils will not be injected with the same vaccine batch used at Ysgol Penweddig last week.

Speaking on Monday night, Dominic's father Paul said he was one of the first on the scene as he worked at a garage nearby: "Dominic is going back to school on Tuesday.

"When I saw a second ambulance turn up at the school last week I knew it must be something serious and I went across.

"I was told that Dominic had suffered a reaction to the injection and had already gone to hospital."

Mr Hamer added that his son had collapsed in the school toilets after feeling unwell. He was discovered by a friend who carried him to teachers and doctors.

The pupils were all taken to Bronglais Hospital

"My wife, Maria, and I later saw him in intensive care - it was a very, very worrying time for us. However, he eventually regained consciousness," he said.

Mr Hamer said four doctors on standby at Ysgol Penweddig during the vaccination process acted swiftly and professionally.

"I must praise the four doctors and all the medical staff involved. The school reacted well too," said Mr Hamer.

"As for the vaccination, if it had only been Dominic who had suffered then we would have said he'd been unlucky. But 13 children in all had problems so something must be wrong.

"However, we urge parents to allow the vaccination procedure to continue because my grandfather died of tuberculosis and I wouldn't want to see that horrible disease making a come back.

"Saying that, there should be a more vigorous investigation into the BCG vaccine."

Ceredigion NHS Trust is investigating and the batch of vaccine has been withdrawn.

Health Minister has Jane Hutt has said there were no grounds for suspecting any fault with the BCG vaccine.