Human papillomavirus genotype-specific prevalence and infection risks: a 10-year population-based study from the United States
Abstract
Background
Various studies have reported on the impact of human papillomavirus (HPV) vaccines. Here we present the largest population-based investigation of genotype-specific distributions over the decade following implementation of the quadrivalent HPV vaccine (HPV-6/11/16/18) in the United States.
Methods
Liquid-based cervical cytology samples from individuals aged 15-30 years undergoing cervical screening throughout New Mexico were tested by broad-spectrum HPV genotyping. Weighted relative differences in HPV type-specific prevalence and 95% confidence intervals (CIs) were calculated by comparing individuals screened between 2007 and 2009 (n = 95 915) with individuals screened between 2013 and 2016 (n = 103 371). Weighted logistic regression was used to estimate relative risk of type-specific HPV infections. Tests of significance were 2-sided.
Results
Genotype-specific prevalence fell with statistical signficance for HPV-16 (relative difference = ‒52.6%, 95% CI = ‒56.9 to ‒48.3), HPV-18 (relative difference = ‒62.1%, 95% CI = ‒68.5 to ‒55.8), HPV-31 (relative difference = ‒34.2%, 95% CI = ‒42.1 to ‒26.3), and HPV-33 (relative difference = ‒31.8%, 95% CI = ‒48.4 to ‒15.1). The relative difference increased for other carcinogenic HPV types by 19.5% (95% CI = 14.3 to 24.6) when excluding HPV-16/18. Large reductions in HPV-6/11 relative differences were observed, but overall, noncarcinogenic, nonvaccine types increased. Comparing female individuals born in 1996 with female individuals born in 1989, risk of infection with HPV-6, 11, 16, and 18 decreased by 80.0% among individuals aged 21-25 years. High-grade squamous intraepithelial lesions or worse decreased by 49.4% when extending the evaluation from 2007 to 2018.
Conclusion
The incidence of high-grade squamous intraepithelial lesions or worse is decreasing, with large reductions in the prevalence of quadrivalent HPV vaccine types and nonvaccine types HPV-31 and HPV-33, reflecting vaccine cross-protection. Increases in nonvaccine HPV genotypes may attenuate anticipated reductions in HPV-related abnormalities, including cancers, but the benefits of HPV vaccination remain substantial.