Nearly half of COVID patients worldwide still have symptoms after 4 months, according to a giant new studyAlmost half of COVID survivors globally—both children and adults—have lingering symptoms four months later, according to a landmark new study.“The reasons as to why so many patients are experiencing long COVID remains unknown,” the authors wrote, adding that possible causes include organ damage, inflammation, altered immune systems, and psychological effects.While some studies have found a higher rate of long COVID in females, the study out of Leicester didn’t find that any particular age group or gender experienced higher rates of the disabling condition.Many experts contend that long COVID is best defined as a chronic-fatigue-syndrome–like condition that develops after COVID illness, similar to other post-viral syndromes that can occur after infection with herpes, Lyme disease, and even Ebola.This story was originally featured on Fortune.comMore from Fortune: Rishi Sunak’s old hedge fund boss paid himself $1.9 million a day this year Meet the 29-year-old teacher with four degrees who wants to join the Great Resignation How much money you need to earn to buy a $400,000 home Elon Musk ‘wanted to punch’ Kanye West after deeming the rapper’s swastika tweet an ‘incitement to violence’"