Asymptomatic testing/ screening

[vuvuzela]

My question pertains to herpes testing following a potential recent  (2 weeks ago) exposure of unprotected vaginal sex (without ejaculation). The status of the recipient is unknown, but from subsequent discussion it seems likely she is relatively promiscuous. She also claims to have had a recent sexual health screen (which was all negative), which would not routinely include herpes testing, but likely did include physical examination. She informs me she has no genital lesion however  is manipulative and unreliable so accurate discussion is not possible
I am completely asymptomatic but concerned about testing for herpes

Specifically

1. What is my likely risk assuming there were no active lesions at the time of intercourse?
2. Why are antibodies to HSV2 so prevalent in the western world given the results of several studies (e.g. NEJM, Jan 2004 – suggesting an approximate 5% annual transmission between discordant couples not engaging in sex during ‘outbreaks’?
3. What is your opinion on screening asymptomatic people?
4. Given that primary infection can be asymptomatic, if i have been infected when is it statistically likely that i would have expected to experience some symptoms (assuming I have been ‘trained’ to spot them now) I am aware that ‘1st presentation’ can be years later, but how common is this
5.             What is your best estimate of single event transmission rates both male-female and female-male?

Many thanks

[Edward W Hook, MD]

Welcome to the Forum. I will go directly to your questions as they address the issues I would state if they had not been asked:

1.  Your risk is low.  Almost no matter how many prior partners your partner had, the likelihood that she has HSV-2 is no greater than 50/50.  In addition, it is clear that, in the absence of lesions, sexual contact with a partner who has HSV-2 results in HSV transmission no more often than once in every thousand exposures and perhaps as rarely as once in every 10,000 sex acts.
2.  HSV is common because the disease is relatively common, because people have lots of sex, and because people typically have more than one sex partner over their life course. Transmission is also facilitated by the fact that only 80-90% of persons with HSV-2 know that they have genital herpes, most often because they have misidentified their symptoms of HSV as something else (denial).
3.  It is not recommended for most persons.  In your specific case and relative to the exposure you mention, if you have not developed lesions by now, two weeks following exposure, it is most unlikely that you got HSV from her.  On the other hand, you may have gotten it at some point in the past.  If you have the blood test at this time you will find out whether or not you have HSV-2 but will have no information as to how long you have had it or where it is.
4.  Primary infection is rarely mis-identified as best we can tell.  It does happen but it is far more common that people acquire infection and then attribute their symptoms to something else.
5.  No data of gender differences in per exposure transmission event.  If lesions are present infection following a single exposure occur no more than 10-20% of the time and as said above, without lesions likelihood is less than 1 in 1000 exposures.

Hope these comments help. EWH

[Edward W Hook, MD]

Correct.  EWH

[vuvuzela]

many thanks for your helpful reply

just to calrify, I assume point 2 should have read 'Transmission is also facilitated by the fact that only 80-90% of persons with HSV-2 DO NOT know that they have genital herpes, most often because they have misidentified their symptoms of HSV as something else (denial)'