Sequential Acquisition of Human Papillomavirus (HPV) Infection of the Anus and Cervix: The Hawaii HPV Cohort Study

Background. Relatively little is known about the epidemiology of anal human papillomavirus (HPV) infection in healthy women and its association with cervical HPV infection. Methods. The association of an incident cervical (or anal) HPV infection with the subsequent risk of a genotype-concordant incident anal (or cervical) HPV infection was examined in a longitudinal cohort study of 751 sexually active women. Age-adjusted hazard ratios, obtained using Cox regression, served as measurements of relative risk (RR). Results. Among women, the RR of acquiring an anal HPV infection after a cervical infection with HPV of the same genotype was 20.5 (95% confidence interval, 16.3-25.7), and the RR of acquiring a cervical HPV infection after an anal infection with HPV of the same genotype was 8.8 (95% confidence interval, 6.4-12.2), compared with women without a previous anal/cervical infection with HPV of a concordant genotype. RRs varied by phylogenetic species, with HPV alpha 3/alpha 15 and alpha 1/alpha 8/alpha 10 types having a greater likelihood than other types of HPV infecting the anus among women with a previous infection at the cervix with HPV of the same genotype. Conclusions. It appears common for anal and cervical HPV infections to occur consecutively. The high degree of genotype-specific concordance suggests that the cervix (vagina) and anus may serve as reservoirs for HPV infection at the other anatomical site.