And how can you protect yourself against them?
A sexually transmitted infection (STI) is any kind of bacterial or viral infection that can be passed on through unprotected sexual contact. And anyone can contract one: it doesn’t matter how many times you’ve had sex, or how many partners you’ve had.
Not every STI has noticeable symptoms, so it can be easy to just hope for the best after having unprotected sex. But there are lots of different types out there, so you should always go and get tested as soon as possible after having unprotected sex so you don’t pass anything to another partner, or cause yourself long-term harm.
It’s understandable that you might feel nervous at the thought of being tested, but don’t worry – most infections are easily treated.
The best defence against catching an STI is to use a condom every time you have sex.
Always remember that condoms are the only contraceptive method out there that protect against both STIs and pregnancy – so even if you’re taking another contraceptive method to protect against pregnancy, like the pill, you should still be rubbering up.
According to the latest figures from the Local Government Association, there were a whopping 78,066 new STI diagnoses among 15 to 19-year-olds, and a ball-busting 141,060 among 20 to 24-year-olds in England at the end of 2015.
Sexually transmitted infections are more common than you might think – and remember, those 200,000 young adults are only the ones who were diagnosed, which means there are probably a whole lot more who don’t realise they might have one.