A senior doctor told an inquest she is "truly sorry" for failings in care that led to a three month old boy dying of sepsis.
Lewys Crawford, from Cardiff, died of meningococcal septicaemia at the city's University Hospital of Wales in March 2019.
Dr Jennifer Evans, a consultant paediatrician who investigated Lewys' death, apologised to his parents.
An inquest is taking place in Pontypridd.
Addressing Lewys' parents, Dr Evans said: "We missed a series of opportunities.
"I'm truly, truly sorry for that."
Lewys should have been given antibiotics within an hour of being seen, rather than the seven hours it took, the inquest heard.
Clinical director of the emergency unit Dr Katja Empson said she was "very sorry" a senior paediatric doctor was not available to assess Lewys when he arrived.
She said if one had seen him, she was in no doubt he would have started antibiotics straight away, adding: "I'm very sorry for that."
Dr Empson said Lewys' parents were "absolutely" right to bring him to A&E.
The inquest heard there were 20 patients in paediatric A&E at the time, and two children were "more unwell" than him.
Although Dr Empson said the volume of patients "was not exceptional", she added: "It will take another couple of years to recruit enough paediatric emergency consultants to cover all week."
She said this is in line with other hospitals.
The inquest continues.