meaning that people that never had sex can get Syphilis, and then spread it in their first sex! Ain't that wacky?
something similar to this but with herpes happened in the 2012 film Excision
the MCs father had to give her CPR as a kid but he had a open coldsore
and she had no idea and was never told she had the virus or carried it as a teenager and she was asymptomatic and she didn't find out until she gave someone else it after her first ever encounter/losing her virginity (also this person was exposed to her blood which heightened the risk) and then her parents finally told her the story about the father giving her CPR as a kid and his coldsore
also besides many other reasons (mostly drug related from what I can remember) this is why it is recommended that if you're trained to give CPR you should invest in a CPR mask to take with you to use in the event where you need to perform CPR on anyone regardless if they have an STD or not
(it's kind of like using gloves now that I think about it and taking precautionary measures and having good hygiene in careers where people handle blood "Treat all blood as if it is infected blood")
or catching something like Mononucleosis also known as The Kissing Disease which I have mostly only encountered/avoided at schools
(which is why even before COVID I stopped using water fountains)