Table 4.

General knowledge (percentage with correct answer) on HPV and cervical cancer among vaccinated and unvaccinated participants on the first and last rounds

	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)

Questions regarding general knowledge were only incorporated in the questionnaires of round one (first) and round five (last). The p-values of vaccinated and unvaccinated girls indicate whether the knowledge changed over time within these groups

^aPreviously published by Mollers et al. [17]