How to rule out HIV?
The risk of getting HIV from single exposure is less.
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You had protected sex with an escort but the condom broke during the act then the risk of getting the HIV infection is there if the girl was HIV positive. The risk from single exposure is obviously less as compared to repeated high risk exposures.
The only way to know for sure whether you have been infected or not is to get tested. I will advice you go for 4th generation HIV DUOS test after one month to get the accurate and reliable result about your condition.
I will also advice you to stay away from unsafe sexual practices to avoid the future risk of HIV and other STDs. Be relaxed without thinking much about HIV and go ahead in life happily with hope for the best.
The risk of transmission is 0.04% if the girl was positive.
HIV is actually relatively hard to transmit. Compare to the cold or flu or herpes, The risk of HIV transmission from female to male during vaginal sex is 0.04%. So be relaxed and get tested after one month to be sure about your status.