[stylin19a]

There has already been a study done that suggested that transmission of HIV is more likely to occur from a person who also has genital ulcers. That study supported the hypothesis that persons who have HIV and genital herpes may transmit HIV infection to others more easily than those who are not HSV-2 infected.

two transmitters in the above cases had genital herpes, which would seem to bias the control.

[Neuromancer]

Your point is well taken.