Sorry, I do not have the references with me to provide this. The figure is an extrapolation from studies by Dr. Anna Wald and her colleagues which evaluated the risk of HSV transmission among participants who took part in "partner studies" in which one partner was known to have HSV and the other was not. These partner studies have been conducted to evaluate prototype vaccines for prevention of HSV-2 and, unfortunately, showed that the vaccine did not work as hoped. Further, just to be clear, this figure is related to risk for transmission in the absence of genital lesions which would be due to asymptomatic viral shedding in an infected person. the data are for persons with genital HSV-2. Genital HSV-1 on average, has substantially lower rates of asymptomatic shedding, hence is lower than for HSV-2. EWH
Thanks very much. I'm afraid your "just to be clear" sentence is confusing me a bit. Are you saying that the figure is related to transmission which occurred from asymptomatic shedding as opposed to genital lesions present during actual outbreaks?
Correct. There are not specific data on the risk of transmission related direcrtly to lesion contact (hard to know how womethng like that would be studied). The assumptom that I and other experts make is that direct lesion contact is likely to be a bit more likely to transmit infection, perhaps 10-fold but if this were the case then the risk would still only be about 1%.
There are, of course many potential variables which could influence risk for transmission following lesion contact including the stage of the lesions, whether the outbreak was an initial one or recurrence, the duration of exposure, etc. EWH