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Dr. Bob
Dr. Bob, Medical Doctor
Category: Urology
Satisfied Customers: 5661
Experience:  20 Years in Internal Medicine, Neurology and Sports Medicine
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Last night (12 hours ago) I met a woman in a bar and we

Customer Question

Last night (12 hours ago) I met a woman in a bar and we ended up having unprotected vaginal sex. I do not know her HIV status. She seemed ok but I know you can't tell just by looking at someone. I have this overwhelming fear that has come over me as I've never done unprotected vaginal sex before, only protected.Should I pursue PEP?
Submitted: 1 year ago.
Category: Urology
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Expert:  Dr. Bob replied 1 year ago.

Hi there. PrEP is recommended when a person is at "substantial risk" of acquiring HIV. The risk from a single event of unprotected vaginal intercourse with a woman who has HIV is only about 1 in 2500. This means you would have to have intercourse about 1250 times with this person for it to be a coin toss. Of course, if the person does not have HIV then you have nothing to worry about except the other STIs out there.

Expert:  Dr. Bob replied 1 year ago.

That said, here are the risk factors for heterosexual sex:

HIV-positive sexual partner

Recent bacterial STI

High number of sex partners

History of inconsistent or no condom use

Commercial sex work

Unprotected sex in high-prevalence area or network

Expert:  Dr. Bob replied 1 year ago.

The best approach here would be to see if your partner from the bar has been tested recently. If negative, this would be very reassuring, though you would still want to get tested yourself at about 2 weeks and 3 months. An HIV antibody response can be detected as early as two weeks in a few people and in more than 99.9% of people by 12 weeks. Testing earlier than 2 weeks is helpful if the test is positive, although it would need to be confirmed. It is not too helpful before 2 weeks if negative (as false negatives are fairly common this early.)

Expert:  Dr. Bob replied 1 year ago.

As for PrEP, your doctor or an HIV specialist might recommend taking it while awaiting testing. This is a judgement call based on all the involved factors. Risks of treatment are very low, so some doctors have a low threshold for prescribing it.

Expert:  Dr. Bob replied 1 year ago.

Let me know if you have any follow up questions about this.