Using data from the Partners PrEP Study , a randomized , placebo-controlled trial of daily oral tenofovir ( TDF ) and emtricitabine/tenofovir ( FTC/TDF ) PrEP among heterosexual HIV-1 serodiscordant couples from Kenya and Uganda , we assessed PrEP efficacy among subgroups at higher risk for HIV-1 acquisition , including subgroups of women with high HIV-1 incidence .