PrEP implementation strategies used in the model.

In strategies I–III, PrEP is initiated following HIV-1 testing of couples, and, in all strategies, PrEP is stopped immediately if the HIV-1–infected partner dies or the initially HIV-1–uninfected partner becomes HIV-1 infected.aIn this and all other scenarios, it is assumed that ART is initiated promptly when the infected partner's CD4 cell count reaches 200 cells/µl.bAn initial period of continued PrEP is allowed until viral load becomes suppressed after ART initiation in the HIV-1–infected partner. PrEP could reasonably be discontinued after an interval of less than 1 y, or be based on viral load monitoring of the infected partner instead.cIn the model, pregnancies can be preceded by a period of “trying to conceive a pregnancy” during which the frequency of unprotected sex increases (see Text S1).