Human Papillomavirus Type 16 and 18 Variants: Race-Related Distribution and Persistence

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Abstract
Background: Analogous to the geographic distribution of variants of human papillomavirus (HPV) types, the distribution and persistence of these variants among infected individuals may be related to the racial composition of a population living in one geographic region. Methods: We studied 1114 women in the United States participating in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study who were positive for HPV16 and/or HPV18 at enrollment. Race was self-reported. HPV samples were characterized by sequencing the E6 gene and part of the long control region and classified as variants according to established lineages. Subjects were examined for HPV every 6 months for 2 years. All statistical tests were two-sided. Results: HPV18 African variants were predominant in the 97 HPV18-infected African American women (i.e., 62 women or 63.9%, 95% confidence interval [CI] = 53.5% to 73.4%), and European variants were common in the 168 HPV18-infected white women (i.e., 91 women or 54.2%, 95% CI = 46.3% to 61.9%). HPV16 African variants accounted for 43 (26.5%, 95% CI = 19.9% to 34.0%) of the infections in the 162 HPV16-infected African American women but for only 25 (4.3%, 95% CI = 2.8% to 6.3%) in the 584 HPV16-infected white women. The likelihood of remaining HPV18 positive was statistically significantly higher in white women infected with European than in white women infected with African variants ( P = .04); the reverse was observed in African American women ( P = .03). A similar pattern was observed for persistence of HPV16 variants, with the likelihood of remaining positive being higher for white women, but lower for African American women, infected with an European variant than with an African variant ( P = .03 and P = .16, respectively). Conclusions: Variants of HPV16 and HPV18 appear to persist longer in a host whose race indicates an ancestral geographic distribution that was once shared with that of the variant—i.e., European variants persist longer in white women, and African variants persist longer in African American women.