Vaccines against oncogenic types of human papillomavirus (HPV) v placebo or no HPV vaccine to prevent vaccine-type HPV-associated cervical cancer precursors in young women (modified intention-to-treat
population)*
| Outcomes at 15–60 months | Number of trials (n) | Weighted event rates | RRR (95% CI) | NNT (CI) | |
| Vaccine | Control | ||||
| Grade 2 CIN or worse | 5 (36 266) | 0.8% | 1.5% | 48% (37 to 57) | 138 (116 to 179) |
| Any grade CIN | 5 (24 613) | 0.7% | 1.9% | 64% (55 to 71) | 81 (73 to 95) |
| Persistent HPV infection at 6 months | 3 (14 207) | 0.9% | 4.0% | 77% (72 to 81) | 33 (31 to 35) |
| Persistent HPV infection at 12 months | 2 (7774) | 0.4% | 1.6% | 74% (59 to 84) | 86 (76 to 108) |
| External genital lesions | 2 (5981) | 1.1% | 3.5% | 69% (56 to 77) | 41 (37 to 51) |
| Serious adverse events | 6 (39 609) | 2.2% | 2.2% | 0% (−14 to 13) | Not significant |
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*CIN = cervical intraepithelial neoplasia; other abbreviations defined in glossary. Weighted event rates, RRR, NNT, and CI calculated from data in article.
