Factors which influence viral load set-point.

Individuals were stratified by sex, age, genital ulcer disease (GUD), viral subtype and paired within couples. Regression coefficients, p-values and R2 adjusted for degrees of freedom, , were reported for single factor models. For the model including all factors the p-value of the couple effect (see methods) and R2 for the couple effect adjusted for confounders, , are presented (see Text S2). The analysis was performed for all 97 couples with moderate support for transmission and for a subset of 29 couples with strong support for genetic linkage.