A "bubbly" young nursery worker has died after testing positive for coronavirus while in hospital awaiting a liver transplant.
Katie Horne's family have been left "completely devastated" by the 21-year-old's death at King's College Hospital in London where she was admitted with a severe liver condition.
Sister Emma said Katie's death should be a "wake-up call" for Britain to take the pandemic seriously, as the death toll continues to surge.
Katie, of Burgess Hill, West Sussex, was not able to be put onto the transplant list due to having Covid-19, her sister claimed.
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She had initially been taken to Princess Royal Hospital in Haywards Heath but was transferred when it became clear she needed a new liver.
Emma said her sister's battle with the liver condition and killer bug lasted just under two weeks, but said she was not put on a ventilator at any point.
She died, suddenly, on Saturday.
The UK's official coronavirus death toll soared above 10,000 after 657 more deaths were reported in England, as well as 24 in Scotland, 18 in Wales and 11 in Northern Ireland.
Speaking to the BBC Emma said: "People need to understand how serious this is."
She added: “If anyone needed anything, you could always count on Kate to be there.
"She was so full of life and happy.
"We just can’t believe it — we are absolutely devastated."
In a Facebook tribute Katie's boyfriend, Jamie Carter, said the virus had played a part in her death.
"It’s with great sadness that we have to inform all of Kate’s friends that she sadly passed away this morning at 5.45am of a short illness and contributing to her death is this devastating coronavirus," he wrote.
"She will always be loved and will forever be in our hearts."
The family are now trying to arrange a funeral during the lockdown, though face the prospect of limited number of mourners and a 20-minute service as crematoriums struggle to cope.
Britain is on course to become the country worst affected by coronavirus in Europe, according to Wellcome Trust director Sir Jeremy Farrar.
Health Secretary Matt Hancock said the future of the virus is 'unknowable' in response to a question about Sir Farrar's statement.
