I was once again visiting Cabo San Lucas and had a questionable encounter with a sex worker (massage parlor).  It was unprotected oral sex.  This was in January 1 (8 days ago). 

I do not have any symptoms, but I am concerned about possible exposure.  The woman did not have any noticeable lesions or signs of infection, but I know that may not be indicative of whether she’s a carrier or infectious.  

I few questions:

1. Is it worth/ advisable to get doses of Rocephin or azithromycin as a preventative measure at this point? Just to get ahead of it in the off chance I did catch something.

2. What are my risks of any sti? 

3. Do you recommend testing and how long do I need to wait to know the results are accurate?

4. In the past I have always had initially positive Syphilis results, but when the labs do a more specific follow up/ confirmatory test, the results come back negative.  Sorry I don’t recall the names of the tests, but the labs have always said that that confirmatory test shows I do not have Syphilis.  Have you seen this before?  Do you know why my initial tests might be coming up as positive?

Thanks in advance for your time!

1.  We recommend against antibiotics “ just in case”.  Antibiotics have their own side effects which all too often just confuse things.  Further, as mentioned, your risk for infection is low.

2.  Your risk for infection is low.  There has never been a proven case of HIV acquired through receipt of oral sex.  Syphilis from oral sex is extraordinarily rare. The most common STIs following oral sex are Gonorrhea or non-chlamydial NGU.  Both are usually symptomatic by 8 days.  If testing would give you peace of mind, testing would be accurate at this time.  I would predict the tests would be negative if you do.

3.  See above.  The most important test would be a urine test for Gonorrhea.

4.  You have had what are called false positive tests for Syphilis.  They occur in about 1% of the population.  The two step testing you describe reliably addresses the problem.

Hope this helps.  EWH 

Have a great day!