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Table 2 Summary of findings table for HPV vaccine versus placebo or no vaccine

From: HPV catch-up vaccination of young women: a systematic review and meta-analysis

Outcomes Illustrative comparative risks* (95% CI) Relative effect (95% CI) No of Participants (studies) Quality of the evidence (GRADE)
  Assumed risk Corresponding risk    
  Placebo, no vaccine or other vaccines HPV vaccines    
Cancer mortality &  
Cervical cancer &  
CIN 2+ ITT (any HPV type) (4-year follow-up) 51 per 1000 41 per 1000 (32 to 52) RR 0.8 (0.62 to 1.02) 39381 (5 studies) moderate1,2
CIN2+ PPP (any HPV type) (4-year follow-up) 29 per 1000 14 per 1000 (6 to 34) RR 0.49 (0.21 to 1.14) 1096 (1 study) low2,3
CIN2+ ITT (any HPV type) (6-year follow-up) 34 per 1000 10 per 1000 (4 to 27) RR 0.29 (0.11 to 0.78) 1002 (1 study) moderate2,4
CIN2+ ITT (any HPV type) (8-year follow-up) 85 per 1000 54 per 1000 (23 to 128) RR 0.64 (0.27 to 1.52) 290 (1 study) low2,5,6
CIN2+ lesions ITT (HPV 16 and/or 18 related) (4- year follow up) 22 per 1000 12 per 1000 (10 to 14) RR 0.54 (0.44 to 0.67) 42652 (7 studies) high2
CIN2+ ITT (HPV 16 and/or 18 related) (8-year follow-up) 31 per 1000 9 per 1000 (3 to 30) RR 0.29 (0.09 to 0.96) 721 (2 studies) moderate4,7
CIN2+ PPP (HPV (16 and/or 18 related) (4- year follow up) 11 per 1000 1 per 1000 (0 to 2) RR 0.05 (0.01 to 0.16) 35023 (6 studies) high2
Genital warts ITT (any HPV type) (4-year follow-up) 40 per 1000 15 per 1000 (13 to 19) RR 0.38 (0.31 to 0.47) 17391 (2 studies) high2
Genital warts ITT (HPV 6 and/or 11 related) (4-5 year follow up) 30 per 1000 8 per 1000 (4 to 19) RR 0.28 (0.12 to 0.65) 21686 (4 studies) high2
VIN2+ and VaIN2+ ITT (any HPV type) (4-year follow-up) 7 per 1000 3 per 1000 (2 to 5) RR 0.49 (0.32 to 0.76) 17391 (2 studies) moderate2,4
VIN2+ and VaIN 2+ ITT (HPV related) (4-5-year follow-up) 4 per 1000 3 per 1000 (0 to 60) RR 0.72 (0.03 to 15.02) 21694 (4 studies) low1,6
Serious Adverse Events (Follow-up: >7 months8, longest reported follow up) 44 per 1000 44 per 1000 (40 to 48) RR 0.99 (0.91 to 1.08) 43342 (14 studies) moderate2,9
  1. *The basis for the assumed risk is the median control group risk across studies. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
  2. CI Confidence interval, RR Risk ratio;
  3. GRADE Working Group grades of evidence.
  4. High quality: Further research is very unlikely to change our confidence in the estimate of effect.
  5. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
  6. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
  7. Very low quality: We are very uncertain about the estimate.
  8. &No studies that reported on overall and cervical cancer mortality, and cervical cancer incidence were identified.
  9. 1I-square >75%.
  10. 2Funded by vaccine provider (we did not downgrade).
  11. 3Few events, high number of loss to follow-up.
  12. 4Few events.
  13. 5Participants were not blinded in this extended follow-up study.
  14. 6Few events and wide confidence interval. Both estimates of relative and absolute effects have wide confidence intervals.
  15. 7Participants were not blinded in one of the extended follow-up studies.
  16. 8We used the longest reported follow-up for each trial.
  17. 9We have reported the results for the safety population as it was defined in each of the studies. Might have led to uncertain loss to follow up. Serious adverse events are defined differently in the studies.