Nothing to worry about?

[biggestfool]

Dr. – The following Q&A was posted on the city of San Francisco website…



QUESTION

If you have herpes, but currently do not have an outbreak, what are the chances of transmitting the virus to another by receiving unprotected oral sex?

ANSWER

In people infected with herpes, the virus is shed about one day a month or 3% of the time. Since we do not know which day that might be, it is estimated that there is an overall maximum 3% risk of transmission over time. Since most people already have Herpes simplex type I (70%) and type II is not that effective at passing from penis to mouth, the risk is likely much lower, but not zero.



My specific questions are as follows:



1) Do you agree with 3% being a good estimate on the chance of getting herpes from unprotected oral sex?

2) If so, would the risk of gonorrhea, syphilis, and the others be lower?  (I ask because I believe you have said in prior posts that the highest STD risk from oral sex is herpes).  

3) If the risks for other STDs are lower, are the risks more “theoretical” than practical?



My story is similar to others in that I foolishly received unprotected oral and protected vaginal sex from a worker at a massage parlour.  I am scared of transmitting something to my wife.  It has only been 2 days since the exposure.  At this point, I do not have any symptoms, but I know it is too early.  Should I get tested after this exposure?  If you agree that my max exposure is within the 3% range, then that will help me with my decision.



Thank you for the wonderful service you provide to this forum!

[H. Hunter Handsfield, M.D.]

In general I avoid commenting on or criticizing other experts' opinions from websites; there is too much risk of differening interpretation depending on context.  But if you are quoting it correctly, that website paints too optimistic a picture for most people at risk for HSV-2.  The average genital-to-genital transmission rate for HSV-2 is 3% per year, not "over time", i.e. the risk is much higher over a long-term relationship.  Further, that rate probably applies only for a long-term monogamous herpes-discordant couple who are being careful about preventing transmission (symptom recognition, condoms).  The risk is far higher for couples in new relationships, especially if the infected person has had herpes for less than a year, and is higher still when the couple is unaware of the infected person's herpes.



Going to your specific questions:



1) No data whatsoever are available on sexual transmission risk for HSV-1, either oral-to-genital or genital-genital (although genital-genital HSV-1 transmission probably is rare). Subclinical shedding of oral HSV-1 appears to be less frequent than for genital HSV-2, and oral-to-genital HSV-1 transmission probably is uncommon if there is no symptomatic cold sore.  But this could be wrong in many individual cases; no research has addressed it.



2) The risk of genital-to-genital chlamydia or gonorrhea transmission is around 20% to 50% per exposure, if one person is infected--MUCH higher than for asymptomatic genital herpes.  For oral-to-genital transmission, all are uncommonly transmitted; gonorrhea is the highest risk among these 3 STDs, and such transmission has never been documented for chlamydia.  Oral syphilis transmission tends to be rare, but that's partly because syphilis is so uncommon in heterosexual men and women in most US populations (including most commercial sex workers).



3) I'm not sure what you mean by theoretical vs practical.  The odds of catching any STD from any single episode or oral sex are very low.



On average, the overall risk of catching any STD undoubtedly is under 5% for any single episode of oral-genital exposure in a massage parlor.  I cannot speculate more precisely than that.  In the absence of symptoms, I do not recommend routine STD/HIV testing after such an exposure.



Good luck--  HHH, MD

[biggestfool]

I forgot to mention...  The unprotected oral lasted 1 min at the most.  Not sure if that makes a difference

[gracefromHHP]

The 3% is an old figure I believe - newer studies put it closer to 15% of days for hsv2 genitally and 18% of days for hsv1 orally as far as viral shedding. If you already have hsv1 orally then you have significant protection against acquiring hsv1 genitally thru oral sex.  Have you ever had a cold sore that you can recall? Have you ever been tested for hsv in the past to know your hsv1 status if you can't recall ever getting a cold sore? Hsv2 doesn't infect the oral area near as often and it's less likely to shed  so you weren't likely to have contracted that orally. Condoms are not 100% protection against hsv2 so definitely follow up with testing for a genital infection.



It's too early to test for herpes and also hiv.  You will need to wait 90-120 days until you can test for it. Should you notice any obvious genital lesions before then see your doctor within 48 hours for a lesion culture and typing.  The risk is low for a one time encounter that is protected but it's not no risk.



In my opinion it's not a bad idea to follow up with your doctor for other std testing until then - better safe than sorry!  It's far easier to tell your wife why you are on antibiotics than it is to explain how she came down with a std while married.



grace

[biggestfool]

I was tested for hsv1 & hsv2 three months ago and was negative.  I will wait to hear the docs advice on the statistics.  If those stats are true, I don't see where unprotected oral could qualify as "low risk" as the Dr. has said before.

[H. Hunter Handsfield, M.D.]

I see I partly misinterpreted your initial question, i.e. limited to oral sex.  But my reply remains accurate, and despite what the other website said, to my knowledge there are no data to support the statitics it quotes on risk of oral-to-genital HSV-1 transmission.  It seems to be citing genital