Anthony Fauci told CNN's "New Day" on Friday that while he didn't want to speculate on Adams' case, "It could be that he continued to have virus in him and that he tested positive and never really got rid of the virus in his system."

"We find that when some people who are immune-compromised that they can have virus lingering on," Fauci said.

"I know nothing about his medical condition so I'm really very reluctant to make any comment about it."

Adams had arrived in Italy ahead of promotional events for Pirelli's 2022 Calendar, which he shot photographs for.

That version of the famed calendar includes images of several stars including Cher, Iggy Pop, Jennifer Hudson and Normani.

CNN has reached out to reps for Adams for comment.