Herpes infects more people worldwide than any other sexually transmitted infection—and it spreads through a simple equation: One partner has the virus. Another partner doesn’t. Any sexual contact between the two can infect the uninfected.
Anal, vaginal, oral, fingering—it doesn’t matter; you can still share the bug. “It all depends on what’s coming into contact with what,” says Aaron Glatt, an infectious disease specialist and spokesperson for the Infectious Diseases Society of America.