The efficacy and duration of vaccine protection against human papillomavirus

Background: The German Standing Committee on Vaccination (STIKO) recommends vaccination against human papillomaviruses (HPV) of the highrisk types 16 and 18. The duration of protection afforded by HPV vaccines has been reported in multiple studies to date but has not been systematically evaluated.

Method: Systematic literature review and meta-analysis on the efficacy of vaccination, with assessment of evidence by the GRADE criteria (Grading of Recommendations Assessment, Development and Evaluation).

Results: 15 studies were identified: 10 randomized controlled trials (RCTs) and 5 observational studies. The RCTs included a total of 46 436 participants. The duration of follow-up was short (median, 3 years) in 8 RCTs and long (median, 6 years) in 2 RCTs. During the period of short-term follow up, the pooled efficacy of vaccination for the study endpoint of incident HPV infection (percentage of infections prevented) was 83% (95% confidence interval [CI]: 70-90%), while the pooled efficacy against persistent HPV infection was 90% (95% CI: 79-95%). In this period, CIN 2+ lesions were prevented with 84% efficacy (95% CI: 50-95%), and CIN 3+ lesions with 94% efficacy (95% CI: 83-98%). During the period of long-term follow-up, incident infections were prevented with 94% efficacy (95% CI: 80-98%) and persistent infections with 95% efficacy (95% CI: 84-99%). The long-term efficacy against CIN 2+ lesions was 86% (95% CI: -166-99%). No data are available on the long-term efficacy of vaccination against CIN 3+ lesions.

Conclusion: Long-term observation does not indicate any loss of antiviral protection after vaccination against HPV 16 and 18, although the evidence for long-term protection is of lesser quality than that for short-term protection.