Great example of FAKE NEWS and really bad reporting.
First of all, WHO did not state that you can catch COVID-19 more than once. They stated that they "they had no evidence" that surviving conferred immunity.
But as kal pointed, out that's not true either. They have plenty of evidence. Over a million people have survived the disease and we don't have a single case of reinfection (yet). There is evidence of SOME immunity.
Bad on the WHO for misinterpreting "evidence" (or lack thereof) and bad on the press for reporting a double negative as a positive.
"We have no evidence that Aliens don't exist" therefore ALIENS EXIST!