Table 2.
Effect of the Intervention on Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium Acquisition
| STI Outcome, Study Group | Women, No. | Events, No. | Person-Years, No. | Incidencea (95% CI) | IRRb (95% CI) | P Value |
|---|---|---|---|---|---|---|
| Combined STIs | ||||||
| Overallc | 177 | 63 | 135.6 | 46.5 (36.3–59.5) | ||
| Intervention | 84 | 22 | 67.4 | 32.6 (21.5–49.6) | 0.54 (.32–.91) | .02 |
| Placebo | 93 | 41 | 68.2 | 60.1 (44.3–81.7) | 1.00 | |
| Individual STIs | ||||||
| C. trachomatis infection | ||||||
| Overall | 205 | 21 | 179.6 | 11.7 (7.6–17.9) | ||
| Intervention | 103 | 7 | 90.0 | 7.8 (3.7–16.3) | 0.50 (.20–1.23) | .13 |
| Placebo | 102 | 14 | 89.6 | 15.6 (9.3–26.4) | 1.00 | |
| N. gonorrhoeae infection | ||||||
| Overall | 218 | 14 | 193.3 | 7.2 (4.3–12.2) | ||
| Intervention | 108 | 5 | 96.3 | 5.2 (2.2–12.5) | 0.56 (.19–1.67) | .30 |
| Placebo | 110 | 9 | 96.9 | 9.3 (4.8–17.8) | 1.00 | |
| M. genitalium infectiond | ||||||
| Overall | 195 | 52 | 155.0 | 33.6 (25.6–44.0) | ||
| Intervention | 94 | 20 | 75.5 | 26.5 (17.1–41.1) | 0.66 (.38–1.15) | .14 |
| Placebo | 101 | 32 | 79.5 | 40.3 (28.5–56.9) | 1.00 | |
Data are for the first incident STI, with follow-up censored at the time of first infection. Each model excludes participants with the STI(s) of interest present at baseline.
Abbreviations: CI, confidence interval; STI, sexually transmitted infection.
a Data denote the number of new STIs per 100 person-years and only include the first STI detected.
b Incidence rate ratios (IRRs) were calculated by Poisson regression models.
c Defined as C. trachomatis or N. gonorrhoeae or M. genitalium infection.
d In addition to the 25 participants with baseline M. genitalium infection, 1 participant was missing baseline results and excluded from the analysis, leaving 195 participants for analysis.