Journal: International journal of cancer
This population-based study from Scotland evaluates the long-term effectiveness of the bivalent HPV vaccine administered since 2008 to girls aged 12-18 years.
Over up to 12 years of routine screening, the data show that a complete vaccine series (three doses or two doses spaced 5 months apart) provided strong protection against cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and grade 3 or worse (CIN3+), with vaccine effectiveness (VE) ranging from approximately 63% to 82%, depending on age at vaccination and lesion severity.
Key findings include:
- Lower effectiveness with incomplete dosing or vaccination at a later age.
- No benefit when vaccination occurred after age 18.
- Women from the most deprived areas had higher baseline incidence but also experienced the greatest reductions after vaccination.
- Evidence of herd immunity was noted across immunized cohorts.
These findings confirm durable vaccine protection and emphasize the critical importance of early, complete vaccination to reduce cervical precancerous lesions.