The Health Protection Agency (HPA) was working alongside NHS Luton to identify why seven schoolchildren became unwell after having injections on January 30. Students from Year 10 at Icknield High School were taken to Luton & Dunstable Hospital as they became ill immediately after receiving the diptheria, tetanus and polio (Td/IPV) vaccine.

A statement from NHS Luton said: "All the children are recovering. Five of the children who showed a reaction have now been released with the final two due to go home this afternoon."

According to NHS Luton, the vaccine was stopped as soon as the children became unwell with 72 students having already been vaccinated.

NHS Luton said: "Both the HPA and ourselves would like to reassure parents that Td/IPV is a safe vaccine and is routinely used in the national vaccination programme. There have been no adverse reactions to this batch of the vaccine which has been in use since April last year."

A spokeswoman for the L&D said: "We had a group of eight school students at the hospital today. All have been seen and none of them required any treatment. There is no evidence to suggest that any of them had a severe reaction."

The GPs of all the students involved have been informed as a precaution.