Among screened couples, 43 (2.5 %) had an HIV-1 risk score of 0–2, 319 (18.8 %) scored 3–4, and 1331 (78.6 %) scored ≥5 (the higher-risk population, Fig. 2). One couple that did not complete screening was not scored. There were 681 HIV-1 serodiscordant couples that were screened for the study but did not enroll: 613 (90.0 %) were not eligible, 66 (9.7 %) were eligible but did not enroll and 2 (0.3 %) did not complete screening. Of the ineligible HIV-1 serodiscordant couples, 252 (41.1 %) had a HIV-1 risk score ≥5 and the main reasons for their ineligibility were advanced clinical HIV-1 disease (41.7 %), infection with hepatitis B (21.8 %) or use of ART (13.9 %). Three-quarters (76 %) of HIV-1 serodiscordant couples scoring ≥5 enrolled into the study. Of the enrolled couples, 479 (47.3 %) scored >7, a level of risk with HIV-1 incidence >7 % per year in prior cohorts .Fig. 2Flow chart of HIV-1 serodiscordant couples screened for eligibility to the Partners Demonstration Project