HPV vaccine offers long-term protection

Vaccination's efficiency against HPV 16 and 18 does not seem to decline during long-term follow up, according to a review of 10 randomised controlled trials – encompassing 46,436 patients – and five observational studies.

During median follow ups of between 25.5 and 27 months, vaccination prevented 83% of new and 90% of chronic (least six months) HPV 16 and HPV 18 infections. Over a median follow up of 36 months, vaccination prevented 84% of cervical intraepithelial neoplasia (CIN) 2+ lesions.

Fewer studies examined the vaccine's longer-term effectiveness. However, one study with a seven-year follow up reported that vaccination prevented 94% of new infections, as well as 86% of CIN 2+ lesions positive for HPV 16 or HPV 18. Based on two studies, vaccination prevented 95% of persistent infections over a median of six years. The long-term efficacy against CIN 3+ lesions is not known.