When Rachel Pope was diagnosed with suspected coronavirus, she did not know it would take a month before she would start to feel better. Or that she would “relapse” the following week, with terrifying kidney, heart and lung pains. 

“It’s very scary,” said the UK-based lecturer, who as of Sunday was on day 70 of her symptoms. “It’s been very changeable — I think as it works its way through different systems.” The woman she suspects she caught the virus from, who first felt symptoms three months ago, is still suffering from fatigue.

The two are not alone in their prolonged illnesses. Around the world there is growing evidence of people with confirmed or suspected Covid-19 suffering symptoms for six weeks or even longer — one more mystery to add to the list of unknowns about the virus and how it affects the human body.