Mike Ryan wasn't quoted correctly. Here is the explanation of his statement from a virtual press conference (COVID-19 Virtual Press conference transcript - 12 October 2020):
AN: Good evening. Hello. This is a question to Dr Ryan. Last week Dr Ryan announced - it was last Monday - that 10% of the world's population might be infected by the COVID so the first ...
Your post links to a BBC News article.
The BBC News article was reporting about a special meeting of WHO leaders that took place on October 5-6, 2020. The BBC article was posted on October 6, 2020.
The WHO meeting and its goals are described here.