Howdy.  I do believe we do have approximations for you!

Of course, in the study that came out last year, I'm not sure how well
they controlled for 2 and 3, but over an eight month period, the virus
was transferred in only 1.9% of couples.

Here's a shortened link that will redirect you to a summary of the
study:

http://makeashorterlink.com/?N26021FE1

For some reason, the discussion we had here at the end of September
last year is mysteriously missing from the Google archive.  I'll
repost in a new thread at least one of the articles that seem to be
missing.

According to the same study, over the same eight month period, in the
placebo group the rate of transmission was 3.8%, which is somewhat
lower than the 9.7% rate we used to regularly quote here.

The rates that I used to quote were (without Valtrex) 4.5% yearly risk
of transfer from female to male, and something like 16.9% from male to
female.  The female's greater mucous membrane exposure is thought to
be the difference.

Take care,

Mike

Here's the old links and blurbs I haven't posted for a while:

http://members.aol.com/herpesite/trans.html#risk
Risk of Transmission
In studies of transmission of genital Herpes in couples, the annual
risk of transmission averaged 5 to 10% per year for those abstaining
from sex during outbreaks. The risk of acquisition was much higher
(16.9%) for women, but somewhat lower for those who already had HSV-1.
There is some evidence that people who have HSV-1 are more resistant
to the HSV-2. This should not be interpreted as immunity but rather as
a higher resistance factor. The transmission rate was also lower for
those who used condoms.

http://www.obgyn.net/english/pubs/features/tfp/solomon_smith.htm
The risk of acquiring HSV-2 among sexual partners was prospectively
analyzed in a study by Bryson et al.(8)   After 16 months of
observation, 14% of initially HSV-2 sero- negative partners
seroconverted. All seroconverters were women, suggesting that women
are at greater risk for acquiring HSV than are men. None of the
couples in which seroconversion occurred used condoms or spermicides
during asymptomatic periods. There was an annual 10% acquisition rate
of HSV-2 among couples.(8)

http://www.viridae.com/gen4.htm?
In a study performed at the Universities of Washington and New Mexico,
heterosexual monogamous patients with genital herpes and their
susceptible partners were counselled on avoiding transmission through
limiting sexual contact to asymptomatic periods. This study was on
selected partners where one partner was known to have type 2 herpes
and the other was known to be susceptible by means of a type-specific
blood test (Western blot). Transmission took place in 14 of 144
susceptible partners (9.7%). In most cases, transmission apparently
took place when the infected partner was asymptomatic. In some cases,
transmission took place during the prodrome or pre-symptomatic period.
Where the gender of the susceptible partner was male (the woman had
herpes), transmission took place, despite avoiding active phases of
infection, with an annual rate of 4.5%. Where the gender of the
susceptible partner was female (the man had herpes), transmission took
place, despite avoiding active phases of infection, with an annual
rate of 18.9%. This study also confirmed that people with pre-existing
immunity to type 1 herpes (eg, by being exposed to cold sores earlier
in life) were partially (but not completely) resistant to subsequent
type 2 genital herpes. It is clearly wise to consider the possibility
that asymptomatic shedding might occur when making personal choices
about preventing herpes transmission. In case asymptomatic shedding
does occur, properly used condoms (safer sex procedures) are the best
protection against transmission and will minimize the low every­day
risk that asymptomatic shedding might lead to asymptomatic
transmission. Using sensitive and strict criteria for identifying
people acquiring herpes, this study showed that avoiding sexual
contact during the active phases of infection provides protection for
more than 95% of susceptible men per year and more than 81% of
susceptible women per year. It clearly showed, however, that simple
avoidance of active phases, alone, was not sufficient to prevent
transmission. To further minimize the risk of transmission to a
susceptible partner, safer sex precautions during asymptomatic periods
should be used.