Table 2.
Univariable longitudinal analysis (using GEE) of sexual risk behavior factors among sexually active participants
| Round 1a | Round 2 | Round 3 | Round 4 | Round 5 | ||||
|---|---|---|---|---|---|---|---|---|
| Category | n (%) | n (%) | n (%) | n (%) | n (%) | p-value | OR (+ 95% CI) | aORc (+ 95% CI) |
| Having had sex for the first time during previous 6 months | ||||||||
| Unvaccinated | – | 84 (22) | 71 (20) | 69 (18) | 59 (17) | 0.01 | Ref | Ref |
| Vaccinated | – | 216 (26) | 166 (20) | 170 (19) | 179 (21) | < 0.01 | 1.15 (0.97–1.37) | 1.14 (0.96–1.35) |
| Lifetime number of sexual partnersb (mean 95%CI) | ||||||||
| Unvaccinated | 2.2 (2.0–2.4) | 2.5 (2.3–2.7) | 2.7 (2.4–3.0) | 3.0 (2.7–3.3) | 3.4 (3.1–3.8) | < 0.01 | Ref | Ref |
| Vaccinated | 1.9 (1.8–2.0) | 2.1 (2.0–2.3) | 2.4 (2.3–2.6) | 2.9 (2.7–3.1) | 3.0 (2.8–3.2) | < 0.01 | − 0.20 (− 0.41–0.00)b | −0.26 (− 0.46 – -0.05) |
| Having a steady partner at the moment | ||||||||
| Unvaccinated | 349 (67) | 275 (71) | 247 (68) | 275 (72) | 250 (72) | 0.17 | Ref | Ref |
| Vaccinated | 729 (68) | 586 (69) | 576 (68) | 622 (68) | 578 (69) | 0.34 | 0.96 (0.82–1.13) | 1.02 (0.87–1.19) |
| Having had a casual partner during previous 6 months | ||||||||
| Unvaccinated | 271 (52) | 96 (25) | 77 (21) | 82 (22) | 81 (23) | < 0.01 | Ref | Ref |
| Vaccinated | 512 (48) | 163 (19) | 170 (20) | 234 (26) | 189 (23) | < 0.01 | 0.92 (0.80–1.06) | 1.11 (0.96–1.29) |
The p-value indicates whether there is a significant change over time. The OR indicates possible differences between vaccinated and unvaccinated participants overall (across all five time points)
- Not asked in this round (Having had sex for the first time during previous 6 months was only questioned from round two onward)
aPreviously published by Mollers et al. [17]
bFor continuous variables, the mean difference was calculated. For other variables, odds ratios were calculated
cOR was adjusted for degree of urbanization and alcohol use