The influence of multiple human papillomavirus types on the risk of genotype-concordant incident infections of the anus and cervix: the Hawaii HPV cohort study.

The influence of multiple human papillomavirus (HPV) types on detection of concordant incident HPV infections of the cervix or anus following infection at the other anatomic site was examined in a cohort of 897 women. Multiple HPV infections at the anus were not significantly associated with subsequent acquisition of a concordant cervical infection, whereas prior coinfections in the cervix increased risk of a new cervical HPV infection. Incident anal HPV infections following concordant cervical HPV infections increased significantly among women with preexisting cervical or anal coinfections. Potential synergy in acquisition of cervical and anal HPV infections has implications for prophylactic vaccine effectiveness.