STD's aren't the sort of thing that Rhys tends to worry about, and not because he hasn't been having much sex. They just aren't really a thing on Umayma.

"Filters," Rhys says. With that he dismisses the grasshoppers and they resume more normal patterns of movement, clustered near him still but no longer deliberately. "And probably not being at war." He glances over at Phillip and then quickly away again, like he's not willing to make eye contact. "Or is this city just far enough from the front?"