Info on STDs and testing below. Read and take action, i.e. get tested!
Depends on the STD, but some transmit pretty easily, and you could be asymptomatic, yet have one or more of them and infect others, let alone the possible long term consequences which are varied (depending on the STD) and potentially lethal.
Sexual health clinics have been set up across NSW to provide a free and confidential service.
The clinics offer testing and treatment of STIs.
They can also talk to you about contraception, other sexual health concerns, and vaccination for hepatitis A and hepatitis B for people at high risk.
The services sexual health clinics offer are free and do not require a Medicare card.
More info from:
https://www.health.nsw.gov.au/sexual...-check-up.aspx
And the list (and map) of NSW sexual health clinics:
https://www.health.nsw.gov.au/sexual...h-clinics.aspx
For your questions on STIs check for example the following page.
It is US based website, so minor differences in occurances, but in general Clamydia seems to be the most common one around the world (unless counting HPV, some form of which most sexually active people get at some point in life).
Clamydia and Gonorrhea transmit fairly easily as they are caused by bacteria.
The good thing thus is that they can be treated with anti-biotics (apart from the anti-biotic resistant strains).
Both (same as others) can have long term helth effects unless treated.
Only about 25% of women and 50% of men get symptoms, so you can be a carrier and infect others even if you don't have symptoms.
https://www.webmd.com/sexual-conditi...ds-men-women#1