Background
Methods
Study design
Measures
Statistical analysis
Results
Participant characteristics and health behavior
Round 1b | Round 2 | Round 3 | Round 4 | Round 5 | |||
---|---|---|---|---|---|---|---|
Category | n (%) | n (%) | n (%) | n (%) | n (%) | p-value | OR (+ 95% CI) |
Participants | |||||||
Unvaccinated | 1051 (100) | 679 (65) | 565 (54) | 572 (54) | 502 (48) | ||
Vaccinated | 1938 (100) | 1361 (70) | 1213 (63) | 1217 (63) | 1072 (55) | ||
Median age (range) | |||||||
Unvaccinated | 17 (16–17) | 17 (17–18) | 18 (18–19) | 19 (18–19) | 19 (19–20) | ||
Vaccinated | 17 (16–17) | 17 (17–18) | 18 (18–19) | 19 (18–19) | 19 (19–20) | ||
More urban areas (> 1000 inhabitants) | |||||||
Unvaccinated | 495 (47) | 315 (47) | 278 (49) | 308 (55) | 282 (57) | < 0.01 | Ref |
Vaccinated | 1019 (53) | 714 (53) | 712 (59) | 734 (61) | 685 (65) | < 0.01 | 1.28 (1.10–1.47) |
Low/Middle Educationa | |||||||
Unvaccinated | 434 (42) | 235 (35) | 189 (34) | 180 (32) | 153 (31) | 0.10 | Ref |
Vaccinated | 779 (40) | 465 (35) | 394 (33) | 386 (32) | 324 (30) | 0.07 | 0.96 (0.83–1.11) |
Ever have used alcohol | |||||||
Unvaccinated | 751 (72) | 507 (76) | 431 (77) | 449 (79) | 389 (78) | < 0.01 | Ref |
Vaccinated | 1509 (78) | 1107 (82) | 988 (82) | 1021 (84) | 888 (83) | < 0.01 | 1.46 (1.24–1.70) |
Ever smoked | |||||||
Unvaccinated | 261 (25) | 176 (26) | 152 (27) | 55 (10) | 52 (10) | < 0.01 | Ref |
Vaccinated | 443 (23) | 330 (24) | 296 (25) | 125 (10) | 107 (10) | < 0.01 | 0.92 (0.79–1.09) |
Ever used contraception | |||||||
Unvaccinated | 640 (64) | 443 (68) | 395 (71) | 420 (75) | 359 (75) | < 0.01 | Ref |
Vaccinated | 1380 (72) | 1038 (78) | 973 (81) | 1020 (85) | 889 (86) | < 0.01 | 1.69 (1.45–1.97) |
Ever had sex | |||||||
Unvaccinated | 525 (52) | 390 (60) | 362 (65) | 383 (70) | 349 (71) | < 0.01 | Ref |
Vaccinated | 1070 (56) | 845 (64) | 845 (71) | 914 (76) | 833 (80) | < 0.01 | (c1) 1.19 (1.02–1.39) |
(c2) 1.30 (1.24–1.35) | |||||||
(c3) 1.06 (1.00–1.12) |
Sexual risk 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) |
Round 1a | Round 2 | Round 3 | Round 4 | Round 5 | OR (+ 95% CI) | aORb (+ 95%CI) | ||
---|---|---|---|---|---|---|---|---|
Category | n (%) | n (%) | n (%) | n (%) | n (%) | p-value | ||
Always using a condom with steady partner during previous 6 months | ||||||||
Unvaccinated | 67 (19) | 59 (22) | 41 (17) | 40 (14) | 34 (14) | < 0.01 | Ref | Ref |
Vaccinated | 126 (17) | 77 (13) | 79 (14) | 65 (10) | 53 (9) | < 0.01 | 0.71 (0.57–0.89) | 0.71 (0.57–0.90) |
Always using a condom with a casual partner during previous 6 months | ||||||||
Unvaccinated | 75 (28) | 27 (28) | 17 (22) | 27 (32) | 20 (26) | 0.12 | Ref | Ref |
Vaccinated | 144 (28) | 50 (31) | 51 (30) | 67 (29) | 44 (23) | 0.97 | 1.00 (0.79–1.28) | 1.00 (0.78–1.28) |
Always using a condom during previous 6 months (combined for casual and steady partner) | ||||||||
Unvaccinated | 93 (20) | 75 (22) | 56 (18) | 59 (18) | 50 (16) | < 0.01 | Ref | Ref |
Vaccinated | 197 (21) | 113 (17) | 117 (16) | 107 (14) | 90 (12) | 0.02 | (c1) 1.01 (0.80–1.27) | 0.85 (0.70–1.02) |
(c2) 0.91 (0.85–0.99) | ||||||||
(c3) 0.91 (0.82–1.00) |
HPV general knowledge
Round 1a | Round 5 | |||
---|---|---|---|---|
Category | n (%) | n (%) | p-value | Mean difference (+ 95% CI) |
General knowledge score (mean 95%CI) | ||||
Unvaccinated | 4.25 (4.14–4.36) | 4.70 (4.54–4.87) | < 0.01 | Ref |
Vaccinated | 4.29 (4.21–4.37) | 4.92 (4.80–5.03) | < 0.01 | 0.11 (− 0.02–0.23) |
HPV infections are easily treatable (No) | ||||
Unvaccinated | 142 (14) | 96 (20) | ||
Vaccinated | 284 (15) | 279 (27) | ||
HPV infections are rare (No) | ||||
Unvaccinated | 428 (42) | 232 (48) | ||
Vaccinated | 882 (46) | 554 (53) | ||
An HPV infection always leads to cervical cancer (No) | ||||
Unvaccinated | 690 (68) | 389 (80) | ||
Vaccinated | 1294 (64) | 844 (81) | ||
Cervical cancer is always fatal (No) | ||||
Unvaccinated | 835 (82) | 427 (88) | ||
Vaccinated | 1579 (82) | 923 (89) | ||
Cervical cancer is easily treatable (No) | ||||
Unvaccinated | 178 (18) | 108 (22) | ||
Vaccinated | 408 (21) | 273 (26) | ||
Cervical cancer is a common disease (No) | ||||
Unvaccinated | 237 (23) | 116 (24) | ||
Vaccinated | 334 (17) | 238 (23) | ||
If you have unprotected sex, you are at high risk of an HPV infection (Yes) | ||||
Unvaccinated | 732 (72) | 345 (71) | ||
Vaccinated | 1411 (74) | 782 (75) | ||
An HPV infection is a risk for cervical cancer (Yes) | ||||
Unvaccinated | 815 (80) | 400 (82) | ||
Vaccinated | 1555 (81) | 888 (85) | ||
An HPV infection can cause genital warts (Yes) | ||||
Unvaccinated | 193 (19) | 134 (28) | ||
Vaccinated | 389 (20) | 274 (26) | ||
An HPV infection usually disappears on its own (Yes) | ||||
Unvaccinated | 56 (6) | 42 (9) | ||
Vaccinated | 80 (4) | 61 (6) |
HPV transmission knowledge
Round 1a | Round 5 | |||
---|---|---|---|---|
Category | n (%) | n (%) | p-value | Mean difference (+ 95% CI) |
Transmission knowledge score (mean 95%CI) | ||||
Unvaccinated | 7.47 (7.39–7.55) | 7.52 (7.40–7.63) | 0.60 | Ref |
Vaccinated | 7.39 (7.33–7.45) | 7.53 (7.46–7.61) | 0.01 | 0.01 (−0.10–0.10) |
HPV can be transmitted by | ||||
Holding Hands (No) | ||||
Unvaccinated | 1002 (99) | 481 (99) | ||
Vaccinated | 1882 (99) | 1034 (99) | ||
Deep throat kissing (No) | ||||
Unvaccinated | 911 (90) | 449 (92) | ||
Vaccinated | 1711 (90) | 968 (93) | ||
Skin-to-skin contact (Yes) | ||||
Unvaccinated | 95 (9) | 36 (7) | ||
Vaccinated | 185 (10) | 71 (7) | ||
Stroking partner at genitals (Yes) | ||||
Unvaccinated | 340 (34) | 126 (26) | ||
Vaccinated | 587 (31) | 258 (25) | ||
Public toilet (No) | ||||
Unvaccinated | 836 (83) | 427 (88) | ||
Vaccinated | 1575 (82) | 927 (89) | ||
Unprotected oral sex (Yes) | ||||
Unvaccinated | 631 (62) | 294 (61) | ||
Vaccinated | 1219 (64) | 640 (62) | ||
Unprotected vaginal sex (Yes) | ||||
Unvaccinated | 967 (95) | 469 (96) | ||
Vaccinated | 1818 (95) | 1004 (97) | ||
Unprotected anal sex (Yes) | ||||
Unvaccinated | 718 (71) | 349 (70) | ||
Vaccinated | 1345 (70) | 766 (71) | ||
Sex with a condom (Yes) | ||||
Unvaccinated | 156 (15) | 95 (20) | ||
Vaccinated | 238 (12) | 157 (15) | ||
Sharing a spoon or cup (No) | ||||
Unvaccinated | 962 (95) | 464 (95) | ||
Vaccinated | 1777 (93) | 999 (96) | ||
Sneezing/coughing (No) | ||||
Unvaccinated | 959 (95) | 470 (97) | ||
Vaccinated | 1794 (93) | 1010 (97) |
Round 1a | Round 2 | Round 3 | Round 4 | Round 5 | |||
---|---|---|---|---|---|---|---|
Category | n (%) | n (%) | n (%) | n (%) | n (%) | p-value | Mean difference (+ 95% CI) |
HPV vaccination score (mean 95%CI) | |||||||
Unvaccinated | 2.50 (2.45–2.54) | 2.46 (2.40–2.52) | 2.59 (2.53–2.65) | 2.60 (2.54–2.65) | 2.67 (2.62–2.73) | < 0.01 | Ref |
Vaccinated | 2.44 (2.41–2.47) | 2.40 (2.36–2.43) | 2.50 (2.46–2.53) | 2.54 (2.51–2.57) | 2.67 (2.64–2.71) | < 0.01 | (b1) -0.07 (−0.12--0.01) |
(b2) 0.03 (0.02–0.04) | |||||||
(b3) 0.02 (0.00–0.04) | |||||||
Vaccination protects against all HPV types (No) | |||||||
Unvaccinated | 701 (70) | 416 (63) | 384 (69) | 388 (69) | 360 (75) | ||
Vaccinated | 1110 (58) | 638 (48) | 665 (55) | 697 (58) | 753 (73) | ||
HPV vaccination protects against all STIs (No) | |||||||
Unvaccinated | 865 (86) | 574 (88) | 518 (93) | 520 (93) | 454 (95) | ||
Vaccinated | 1702 (89) | 1246 (94) | 1144 (95) | 1159 (97) | 1008 (97) | ||
Condoms are not needed anymore once vaccinated (No) | |||||||
Unvaccinated | 939 (94) | 623 (95) | 542 (97) | 545 (98) | 468 (98) | ||
Vaccinated | 1842 (97) | 1297 (98) | 1187 (99) | 1186 (99) | 1016 (98) |