Hospital bosses have apologised to the parents of a premature baby, saying their failure to give him "timely" antibiotics contributed to his death.
Ben Condon died in Bristol Royal Hospital for Children on April 17 2015 after developing acute respiratory distress syndrome mostly likely caused by human metapneumovirus (hMPV) - like the common cold in adults.
His parents, Olympian Allyn and Jenny Condon, from Weston-super-Mare, Somerset, vowed to "continue to seek for the truth" following an inquest into his death which concluded last year.
They told the hearing they believed Ben should have been given antibiotics in the days leading up to his death but Avon Coroner's Court heard this would not have prevented it.
On Thursday, the chief executive of University Hospitals Bristol NHS Foundation Trust, Robert Woolley, said he accepted there were failings in Ben's care and had written to his parents to say sorry.
"I would like to publicly apologise to Mr and Mrs Condon," he said.
"We failed to take the opportunity to give Ben timely antibiotics and this contributed to his death.
"I am also deeply sorry for the additional distress and hurt caused by the wait Mr and Mrs Condon have endured before receiving this explanation."
Ben was born at 29 weeks at Southmead Hospital in Bristol on February 17 2015 and spent seven weeks being cared for in the paediatric intensive care unit before being allowed home on April 7.
Ben, who weighed just 5lb, began coughing and sneezing two days later and was taken to Weston General Hospital and transferred to Bristol Royal Hospital for Children after becoming lifeless and struggling to breathe on April 10.
During the inquest, his parents said they were repeatedly assured that Ben would be given antibiotics from April 15 when X-rays showed a change in his lungs.
Ben was prescribed antibiotics at 3pm on April 17 but these were not administered until 8pm. By that time he had suffered a cardiac arrest and doctors were carrying out life-saving treatment.
He died at 9.07pm, having suffered a second cardiac arrest.
Coroner Maria Voisin said Ben's death was caused by acute respiratory distress syndrome, hMPV and prematurity.
The Trust said Mr Condon brought a claim for clinical negligence earlier this year on his son's behalf, based on the failure to give Ben antibiotics on April 16 2015, which resulted in a further extensive review of the circumstances of his death, including obtaining additional and further clinical and expert evidence and advice.
The Trust said Ben's case was "very complex" and there were a "range of different views" on whether and when he should have been given antibiotics, which was the reason for the delay in "clarifying the Trust's position".
Dr Bryony Strachan, clinical chairwoman for the Division of Women and Children's Services, said she hoped Mr and Mrs Condon could take "some comfort that we have learnt lessons from this and that we have already made changes and improvements in light of their and Ben's experience in our care".
She added: "We also know that the way we responded to Ben's parents at times added to their distress and we are very sorry for that."
Changes made include investment in bereavement support, a new electronic information system on the children's intensive care unit recording everything happening to a child, and the review and update of guidelines for treating acute lung problems in children.