Authors of the study said the observed death rates put the illness on a par with Ebola

A third of patients admitted to hospital in the UK with Covid-19 are dying, according to a major study whose authors said the observed death rates put the illness on a par with Ebola.

The study tracked the outcomes of nearly 17,000 patients – around one-third of all those admitted to hospital in the UK – and found that 33% had died, 49% were discharged and 17% were still receiving treatment after two weeks.

The figures present a stark picture of outcomes for those whose illness escalates to the point of needing medical help.

“Some people persist in believing that Covid-19 is no worse than a bad dose of flu. They are gravely mistaken,” said Calum Semple, professor in child health and outbreak medicine at the University of Liverpool, and chief investigator of the study.

“Despite the best supportive care that we can provide, the crude case fatality rate for people who are admitted to hospital with severe Covid-19 is 35% to 40% which is similar to that for people admitted to hospital with Ebola.”

The average Ebola case fatality rate is around 50%, according to the World Health Organization, although case fatality rates have varied from 25% to 90% in past outbreaks.

“People need to hear this and get it into their heads,” Semple added. “The reason the government is keen to keep people to stay at home until the outbreak is quietening down is because this is an incredibly dangerous disease.”

Peter Openshaw, professor of experimental medicine at Imperial College London, and co-lead of the study, said: “Those are extraordinarily sobering figures. All those hard data glosses over the human tragedy that each of those cases represents.”

The study, published as a preprint and not yet peer reviewed, found that of those admitted to hospital, 17% ended up going into intensive care units (ICUs). Of these, 45% died and for those receiving mechanical ventilation, the death rate rose to 53%, with 27% remaining in hospital when their outcome was recorded. For those on hospital wards, the fatality rate was 31%.

The authors said that many patients are not transferred to ICU for more intensive interventions because this would be the wrong clinical decision, not due to bed shortages.

“ICU is not something where the sickest patients all come to die,” said Dr Annemarie Docherty, a consultant in critical care and researcher at the University of Edinburgh. “We have specific tools like ventilation, renal support for kidneys, that we can deliver while people get better. For Covid, all we can offer is organ support while people are getting better. For a large number of people in hospital this is just not appropriate and people are unlikely to improve with these interventions.”

The study also revealed more about which groups are most vulnerable, with men being more likely to be admitted to ICU and more likely to die, with differences becoming more striking in older age groups. The most significant health risk factor was obesity, increasing risk of death by 37% – a greater amount than heart disease (31%), lung disease (19%) or kidney disease (25%).

The link to obesity could be due to the condition typically causing related problems in the lungs and kidneys and because fat cells increase the body’s inflammatory state.

“Nobody who is a big person is a big person in isolation,” said Semple, adding that obesity is also strongly associated with socio-economic status. “Together that makes it a very tough ride for these people when they catch Covid,” he said.

Semple said the findings could influence who the government identifies as high risk for shielding policies as the lockdown is lifted and that the team is developing an interactive tool that will allow people to get a better sense of their own risk, based on sex, age and co-morbidities.

Why the UK is finding it so hard to reach 100,000 Covid-19 tests a day Read more

The study was carried out by a consortium of researchers across more than 160 hospitals, which has now recruited 25,000 patients, and taken biological samples from 1,000 of them, making it the largest study in Europe on outcomes and risk factors. The team is also looking closely at why a disproportionate number of admissions and deaths are seen in black people and those from south-east Asian backgrounds.

Semple said that crucial lessons could be learnt from how the Ebola epidemic was brought under control. “Key to eradicating Ebola was the provision of same-day or next-morning reporting of test results which allowed proper isolation of cases and rapid release from confinement for suspected cases,” he said. “It will be the same for Covid-19. We need widespread rapid access to same-day or next-morning test results to keep Covid-19 at bay which in turn will allow our society and economy to regain function.”