Determining what constitutes a false claim regarding the COVID-19 shot is much harder than fact-checking a claim about an established vaccine with a proven safety record, Facebook fact-checkers told Reuters.

“There is a lot of content that we see and we don’t even know what to do with it,” echoed Emmanuel Vincent, founder of Science Feedback, another Facebook fact-checking partner, who said the number of vaccines in development made it difficult to debunk claims about how a shot would work.