Efficacy of bivalent, quadrivalent and nonavalent vaccines against human papillomavirus and cervical intraepithelial lesions: A systematic review

Purpose: To investigate the effectiveness of bivalent (2v), quadrivalent (4v) and nonavalent (9v) vaccines against human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN). Methods: This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and involved an electronic search of studies published from 2018 to 2023. The efficacy of each vaccine was evaluated by comparing the number of vaccinated individuals with the number of positive cases using a 95 % confidence interval (CI). Results: The overall effectiveness of the 2v, 4v and 9v vaccines against CIN was 87.23 %, 99.85 and 97.7 %, respectively. Based on 95 % CIs, the vaccine efficacies for CIN 1, CIN 2, CIN 3 and > 6 months of persistent infection were 87.4, 86.2, 88.08 and 95.92 % for the 2v vaccine; 99.56, 100, 100 and 75.9 % for the 4v vaccine; and 98, 96.3, 99 and 96 % for the 9v vaccine, respectively. The 4vHPV vaccine was the most effective against HPV types in terms of protection against different stages of CIN. However, the 9vHPV vaccine was highly effective and offered protection against most HPV types. Conclusion: The 9vHPV vaccine is highly effective and thus an ideal choice for HPV and CIN as it offers protection against most HPV types.