Thank you for asking Healthcare majic. My name is Dr Ehsan Ullah & I have gone through your query. First of all, the things you mentioned here as having properly protected sex with the sex worker where all the time you have used the protective measures then obviously almost No chance of contracting any STD like HIV. second; Not all the sex workers are HIV +. Third; you have mentioned here the Oral sex and one of your concern in a question is can HIV be contracted via Oral sex? well, it has very little or even No chances to get such infections unless ejaculated in mouth like in case , some males ejaculate after withdrawing penis from vagina into sex partner s mouth. that carries some risk. Most types of oral sex carry little to no risk of HIV. Your highest oral sex risk is performing oral sex (fellatio) with ejaculation in your mouth. However, the risk is still low, and much lower than anal or vaginal sex. Factors that may increase the risk of transmitting HIV through oral sex are oral ulcers, bleeding gums, genital sores, and the presence of other sexually transmitted diseases Oral sex is much less risky than anal or vaginal sex. Anal sex is the highest-risk sexual activity for HIV transmission. If you are HIV-negative, insertive anal sex (topping) is less risky for getting HIV than receptive anal sex (bottoming). Sexual activities that do not involve the potential exchange of bodily fluids carry no risk for getting HIV (e.g., touching). Condoms are also effective at preventing sexually transmitted diseases (STDs) transmitted through body fluids, like gonorrhea, chlamydia, and HIV. However, they provide less protection against STDs spread through skin-to-skin contact like human papillomavirus (genital warts), genital herpes, and syphilis. What condoms are better? Latex condoms give best protection while use of lubricants lowers the risk of rupture of condoms. Hope this may help you. kindly write a review & Let me know if anything not clear. Thanks.