Tests showed that he had astonishingly high levels of a marker for the amount of clotting in the blood known as D-dimer.
Normally these are less than 300, and in stroke patients can rise to 1,000. Paul Mylrea's levels were over 80,000.
"I've never seen that level of clotting before - something about his body's response to the infection had caused his blood to become incredibly sticky," says Dr Chandratheva.
"Sars and Mers, which are both caused by coronaviruses, were associated with some neurological disease, but we've never seen anything like this before," Dr Michael Zandi, consultant neurologist at the NHNN, told me. "The closest comparison is the 1918 flu pandemic. We saw then there was a lot of brain disease and problems that emerged over the next 10-20 years."
