Threshold for sustainable transmission and transmission probability per partnership for key sexually transmitted infections*.

*Appendix S1 includes the formulae used for our calculations for HIV and HSV-2. The values for the rest of the STIs are extracted from the cited references.?Note that although HSV-2 transmission probability per partnership is not much larger than that of HIV, HSV-2 infectious spread is much more invasive since the absence of disease mortality allows HSV-2 infected persons to spread the infection in more sexual partnerships over their lifetime.?The minimum effective new sexual partner acquisition rate is calculated assuming mean representative partnership duration of six months (Protocol S2).