Here's some info from the CDC about HIV/AIDS.
Here's some info about prevention. That site has great information about HIV. There is a TON of misinformation out there.
The bottom line is that if you use condoms correctly, EVERY TIME, for vaginal and anal sex, and do not share needles if you inject drugs, you will not become HIV positive.
If a condom breaks and you do not know your partner's HIV status, you can talk to your doctor about
PEP.
There have been several peer reviewed studies of serodiscordant couples who used condoms for vaginal and anal sex every time but never for oral sex. None of the HIV- partners seroconverted in any of these studies. Do not believe the misinformation.
The CDC says there is little to no risk of acquiring HIV from oral sex.
Unlike the fragile HIV virus, other infections are easy to transmit.
Using a condom correctly every time results in a 90% reduced risk of gonorrhea and a 60% reduced risk of chlamydia.
Condoms also prevent syphilis, but not if your partner has sores that are not covered by the condom.
If you have oral sex without a condom there is a risk of the three infections mentioned above. The good news is that all three are usually cured quite easily with antibiotics.
The best way to prevent HSV (herpes) is to not have sexual contact with someone who has sores on their mouth or genitals.
If you are a man and use a condom for everything, there is
a 2% chance of getting HSV-2 (genital herpes). Cold sores are HSV-1 and can be transferred from mouth to genitals.
Most of the population has this type of herpes.
The CDC says there aren't any dependable large scale studies that have been done on sex workers to determine whether or not the rate of STIs in the population differs from that of the general population.
St. James Infirmary is working on getting better data though!
It's impossible to put a % on whether or not you will contract an STI from a sexual encounter if you are not 100% sure of your partner's status. If your partner has no STIs, you have a 0% chance! If you use condoms for vaginal and anal sex, you will almost definitely not contract HIV. Using condoms correctly, every time, is good protection against most STIs.
Many people think they are using condoms directly and are not. Please
read up on correct condom use if you are sexually active!
If you are sexually active it is best to get tested every 3-6 months for HIV, gonorrhea, chlamydia, and syphilis. HIV tests are free in New Orleans at several different locations, and many of these locations do a rapid test so you can get your results in 15 minutes.
Everything in life has risks. 1.3 million people die in car crashes in the US every year, yet a lot of us still choose to drive. There’s a one in 100,000 chance of passing away at a dance party,
apparently. The best thing to do is to educate yourself and decide if the benefits of something you'd like to do outweigh the risk.
Be safe!
Tl;dr: Use condoms.