A hospital launched an investigation today after a newborn baby was given an overdose of a tuberculosis vaccine.
The boy, who was born on February 5, was injected with 0.5mg of the BCG vaccine - 10 times the usual 0.05mg dose, lawyers for his family said.
A statement from law firm Irwin Mitchell said the boy is now being treated with help from the poisons agency and an expert in immunology at Sheffield Children's Hospital.
A spokesman for Scunthorpe General Hospital said it had launched a "full investigation".
Speaking on behalf of the family, who wish to remain anonymous, David Body, a medical law specialist at Irwin Mitchell, said: "This is a difficult time for the baby's family.
"Their baby is receiving treatment for TB, which has its own side-effects, but they are hopeful that the treatment will be successful with no long-term damage to their baby's health.
"However, this case raises important questions about basic systems in hospitals to ensure the safe administration of drugs, including vaccines."
Mr Body said the firm would also follow up reports that other such cases had occurred at the hospital.
He added: "It is important that we get answers about how and why this has happened.
"It is unclear how many people have been affected but we have received reports that others may also have been given the same overdose."
Simon Rigg, a spokesman for Scunthorpe General Hospital, said authorities would keep in touch with the family for as long as the investigation lasted, which at present was unknown.
He said: "We launched a full investigation as soon as we found out about the incident.
"That investigation is ongoing and we will continue to keep the parents informed as to the progress of that investigation."