Sepsis deaths recorded in hospitals rose by more than a third in two years
William died from sepsis following a chest infection in December 2014. An expert at the inquest into his death in June 2015 said that had William's condition been recognised and treated earlier, there is a good chance he would have survived.
Responding to the report that sepsis killed 15,722 people in the year ending April 2017, Melissa Meade, who has been campaigning since her son's death, said that lack of public awareness about sepsis means "there will be people sitting at home feeling poorly who don't even realise sepsis is a thing".
"We need to be looking at this from all angles," Melissa said. "It's all very well having a world-class health system with surplus beds and surplus doctors, but if I'm sitting on my sofa at home feeling poorly and I don't know what sepsis is, I'm not going to get that care.
"It's making sure that every route is connected, that people have the information to make informed decisions about their onward care, and that when they access that care that they are listened to and their concerns are acted upon promptly."
In a similar case run by Mark Bowman, an eight-month-old baby (Christopher) died from meningococcal septicaemia when a junior doctor at the University College Hospital London (UCL) diagnosed tonsillitis and sent the family home. Meningitis because of infection can lead to sepsis.
Prof Sir Brian Jarman who wrote the recent report said he believes staff shortages and overcrowding on wards are partly to blame for an increase in sepsis. Sir Brian, director of the Dr Foster research unit at Imperial College in London, wants his data to be used to improve the survival chances of hospital patients who developed sepsis, via alerts that he sends to hospitals that are falling behind.
There has been a focus on screening for sepsis in the NHS in recent years, led by the UK Sepsis Trust, which confirmed that sepsis was one of the most common causes of death in the UK, responsible for killing up to 44,000 people a year - in hospital and in the community.
A spokesperson for the trust said that "treatment for sepsis, if it's caught early enough, involves very basic interventions - looking for the source of the infection, giving antibiotics.
"For every hour we delay in giving antibiotics, the patient's risk of dying increases by a few per cent, so it's essential that we spot it early and deliver the basics of care quickly."
Sir Brian said: "The biggest thing that's important seems to be the number of staff - doctors per bed.
"One of the secondary important things is the overcrowding of hospitals. The level of overcrowding shouldn't be more than 85% [bed occupancy], and it's been going over 90% in recent years."
But Professor Bryan Williams, chair of medicine at University College London, said that increased awareness and detection of sepsis meant more cases of sepsis were actually being picked up, which contributed to the rise in numbers.
He said it was important for the public to recognise that the NHS was taking sepsis "incredibly seriously".
"If you go to any hospital now it is treated as one of the priorities and death rates are falling," he said.
An NHS England spokesperson was quoted by the BBC: "Over the past three years there has been huge effort across the NHS to increase clinical recognition of, and recording of, sepsis.
"That improved method of recording means some cases previously recorded as simple infections are now classified as sepsis. So this data does not prove an increase in sepsis cases per se."