Table 1.
Baseline Characteristics of the Study Participants, According to Study Group.*
| Characteristic | Total (N = 5029) |
Oral TDF (N = 1007) |
Oral TDF-FTC (N = 1003) |
Oral Placebo (N = 1009) |
TFV Gel (N = 1007) |
Placebo Gel (N = 1003) |
|---|---|---|---|---|---|---|
| Age — yr | ||||||
| Mean | 25.3±5.2 | 25.5±5.1 | 25.2±5.2 | 25.3±5.2 | 25.3±5.2 | 25.3±5.1 |
| Median (range) | 24 (18–40) | 25 (18–40) | 24 (18–40) | 24 (18–40) | 24 (18–40) | 24 (18–40) |
| Some secondary school education or higher — no. (%) | 4622 (92) | 924 (92) | 929 (93) | 926 (92) | 920 (91) | 923 (92) |
| Earns own income — no. (%) | 2881 (57) | 569 (57) | 569 (57) | 586 (58) | 587 (58) | 570 (57) |
| Live births — no. | 1.5±1.1 | 1.6±1.1 | 1.5±1.1 | 1.5±1.2 | 1.5±1.1 | 1.5±1.2 |
| Currently married — no. (%) | 1052 (21) | 207 (21) | 209 (21) | 211 (21) | 210 (21) | 215 (21) |
| ≥2 male sex partners in the past 3 months — no./total no. (%) | 1104/4991 (22) | 236/1001 (24) | 208/994 (21) | 244/1003 (24) | 217/998 (22) | 199/995 (20) |
| Episodes of vaginal intercourse in the past 7 days — no.† | 2.5±3.1 | 2.5±2.8 | 2.5±3.4 | 2.5±2.6 | 2.6±3.6 | 2.6±2.9 |
| Condom use during last vaginal sex — no./total no. (%) | 3766/4420 (85) | 763/880 (87) | 760/888 (86) | 742/872 (85) | 768/895 (86) | 733/885 (83) |
| Anal sex in the previous 3 mo — no./total no. (%) | 868/4991 (17) | 164/1001 (16) | 175/994 (18) | 174/1003 (17) | 179/998 (18) | 176/995 (18) |
| Contraception method — no. (%) | ||||||
| Injectable | 3565 (71) | 709 (70) | 723 (72) | 700 (69) | 707 (70) | 726 (72) |
| Oral pills | 1140 (23) | 226 (22) | 223 (22) | 238 (24) | 238 (24) | 215 (21) |
| Infection present | ||||||
| Chlamydia trachomatis — no. (%)‡ | 611 (12) | 122 (12) | 117 (12) | 127 (13) | 116 (12) | 129 (13) |
| Neisseria gonorrhoeae — no. (%)‡ | 163 (3) | 42 (4) | 27 (3) | 34 (3) | 24 (2) | 36 (4) |
| Trichomonas vaginalis — no. (%)§ | 301 (6) | 68 (7) | 54 (5) | 66 (7) | 62 (6) | 51 (5) |
| Syphilis — no. (%)¶ | 68 (1) | 12 (1) | 15 (1) | 16 (2) | 14 (1) | 11 (1) |
| HSV-2 — no./total no. (%)‖ | 2289/5005 (46) | 482/1002 (48) | 449/997 (45) | 455/1006 (45) | 438/1004 (44) | 465/996 (47) |
| Bacterial vaginosis — no./ total no. (%)** | 2023/5010 (40) | 422/1000 (42) | 410/1002 (41) | 401/1008 (40) | 397/1003 (40) | 393/997 (39) |
Plus–minus values are means ±SD. FTC denotes emtricitabine, HSV-2 herpes simplex virus type 2, TDF tenofovir disoproxil fumarate, and TFV tenofovir.
Data on the number of sex acts in the past 7 days were available for 4566 participants.
Testing for C. trachomatis and N. gonorrhoeae was performed with the use of a strand-displacement amplification assay (BD ProbeTec, Becton Dickinson).
Testing for T. vaginalis was performed with the use of the OSOM Trichomonas Rapid Test (Genzyme).
Syphilis testing was performed with the use of a rapid plasma reagin screening test followed by a confirmatory microhemagglutinin assay for Treponema pallidum or a T. pallidum hemagglutination assay for reactive samples.
HSV-2 seropositivity was determined with the use of the HerpeSelect 2 enzyme immunoassay (Focus Technologies) at the time of enrollment; an index value of 3.5 or greater was considered to be a positive result.
Bacterial vaginosis was determined by the Nugent score on Gram’s staining of vaginal fluid.