An eight-week-old baby boy died after a "catalogue of failings" in his care at a hospital in Bristol, an independent report has found.
Ben Condon died in Bristol Royal Hospital for Children on 17 April 2015 after developing acute respiratory distress syndrome mostly likely caused by human metapneumovirus (hMPV) - like the common cold in adults.
The University Hospitals Bristol and Weston NHS Foundation Trust has previously admitted that failure to give Ben timely antibiotics contributed to his death.
His parents, Olympic athlete Allyn and Jenny Condon, from Weston-super-Mare, complained to the Parliamentary and Health Service Ombudsman about his care.
The ombudsman found doctors were aware of Ben's deterioration on the day he died and "did not provide him with the treatment he needed as promptly as they should have done".
"We find that Ben and his family suffered serious injustice in consequence of the failings we found in his care and treatment," the ombudsman said.
"This is because the failings we found - which are in addition to the accepted failure to give Ben antibiotics - were all lost opportunities to intervene and give Ben the best possible chance of recovering from his illness.
"Each one of the failings would have reduced the chances of the best possible outcome for Ben."
The report found Mr and Mrs Condon suffered a "serious injustice" in the way the trust responded to their questions after Ben died and in its handling of their complaints.
The ombudsman said doctors and nurses did not "respond appropriately" to his parents' concerns about their son's low temperature or tell them how ill he was.
Although Mr and Mrs Condon have accused the trust of a "cover-up", the report said the trust's actions in failing to be "open and honest" about Ben's death could be seen as a "deliberate attempt to deceive".
Ben was born at 29 weeks at Southmead Hospital on 17 February 2015 and spent seven weeks being cared for in the paediatric intensive care unit before being allowed home on 7 April.
Ben, who weighed just 5lb, began coughing and sneezing two days later and was taken to Weston General Hospital before he was transferred to Bristol Royal Hospital for Children after becoming lifeless and struggling to breathe three days later.
An inquest into his death heard his parents said they were repeatedly assured Ben would be given antibiotics from 15 April, when X-rays showed a change in his lungs.
Ben was prescribed antibiotics at 3pm on 17 April 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.
Mr Condon said: "It is now six years since Ben's death and nearly four years since the ombudsman began investigating.
"We hope that the truth of what happened to Ben will now, finally, be clearer and that we are closer to getting the justice we have fought so hard for.
"Our constant desire has been to ensure that what happened to Ben does not happen to another child.
"Our fight over the years is not just about justice for Ben, but to also ensure that lessons are learnt from what happened so that no other family suffers as we have, either because of the avoidable death of their child, or the way failings in care have been covered-up afterwards.
"Many other families out there are in similar positions to us. Our message to them is to keep fighting for the truth."
Novum Law lawyer Mary Smith, who represents the Condon family, said: "Allyn and Jenny have fought tirelessly for years to expose the truth of what happened to Ben.
"No family should have to endure what they have had to suffer.
"Hospital trusts and those working for them should be open and honest with families from the outset.
"It cannot be right that bereaved families are put through further significant trauma by having to battle to uncover for themselves what happened to their loved one."
Robert Woolley, Chief Executive of University Hospitals Bristol and Weston NHS Foundation Trust said:
“We have fully contributed to the independent review carried out by the Parliamentary and Health Service Ombudsman (PHSO).
“We have previously accepted, and apologised for, failings that were made in Ben’s care and our communication with his family. We have accepted the failure to give timely antibiotics made a material contribution to Ben’s death in 2015.
“I would like to reiterate this apology on behalf of the Trust and again extend mydeepest condolences to Mr and Mrs Condon and their family.
“We will take forward the recommendations in the report to summarise all the learning and improvements we have made in how we handle complaints and communication with families, together with a robust action plan where required.”