Table 1.

Efficacy of HPV vaccination on all-type cervical abnormalities in HPV-naïve women reported in the literature

Study	Study design	Setting/year	Study population (stratum of study population included)	Outcome measure reported	Reported vaccine efficacy, % reduction (95% CI)
					ASCUS+	Any cervical biopsy	CIN2+	CIN3+
Munoz et al27	Randomised controlled trial	Multinational 2001–2006	16–26 years+several other criteria*	Rate ratio	17.1 (10 to 23)	22 (16 to 30)	42.7 (23.7 to 57.3)	43† (13.0 to 63.2)
Crowe et al28	Nested case–control study	Queensland, Australia 2007–2011	15–18 years in 2007, presenting for first smear, received all 3 doses of vaccine	OR	NA	NA	60 (44 to 70)‡	NA
Gertig et al25	Data linkage study	Victoria, Australia 2007–2011	≤17 years in 2007, had started cervical screening, received all 3 doses of vaccine	HR	NA	NA	39 (22 to 52)	47 (23 to 64)
Baldur-Felskov et al36	Cohort study	Denmark 2006–2012	14–15 years in 2008 (1993–1994 cohort), had a history of cervical cytology	HR	§	NA	67 (17 to 87)	75* 10 to 93)
Mahmud et al37	Cohort study	Manitoba, Canada 2006–2011	14–17 years in 2006–2010, had ≥1 Pap smear	HR	45 (32 to 56)	NA	NA	NA
Pooled estimate					32	22	49	47

*(1) Participants had 0–4 sex partners during their lifetime; (2) no history of abnormal Pap smear test; (3) no history of genital warts; (4) no genital wart detected at enrolment; (5) received at least one vaccination; (6) were seronegative; HPV 6, 11, 16 and 18 negative, and negative for 10 other HPV types at enrolment; (7) had a negative day 1 Pap smear test and (8) had any follow-up visit.

†The reported vaccine effect is on CIN3, not CIN3+. No cases of higher grade of severity are reported.

‡Relative risk calculated from reported data.

§Vaccine efficacy on ‘atypia or worse’ of 53% is not included in our pooled estimate, because this classification includes reactive changes.

ASCUS, Atypical Squamous Cells of Undetermined Significance; CIN, cervical intraepithelial neoplasia; HPV, human papillomavirus; NA, not applicable.