Glenn Copeland

Prevalence of human papillomavirus genotypes in high‐grade cervical precancer and invasive cervical cancer from cancer registries before and after vaccine introduction in the United States

BackgroundUS population‐based cancer registries can be used for surveillance of human papillomavirus (HPV) types found in HPV‐associated cancers. Using this framework, HPV prevalence among high‐grade cervical precancers and invasive cervical cancers were compared before and after HPV vaccine availability.MethodsArchived tissue from 2 studies of cervical precancers and invasive cervical cancers diagnosed from 1993‐2005 (prevaccine) were identified from 7 central cancer registries in Florida; Hawaii; Iowa; Kentucky; Louisiana; Los Angeles County, California; and Michigan; from 2014 through 2015 (postvaccine) cases were identified from 3 registries in Iowa, Kentucky, and Louisiana. HPV testing was performed using L1 consensus polymerase chain reaction analysis. HPV‐type–specific prevalence was examined grouped by hierarchical attribution to vaccine types: HPV 16, 18, HPV 31, 33, 45, 52, 58, other oncogenic HPV types, and other types/HPV negative. Generalized logit models were used to compare HPV prevalence in the prevaccine study to the postvaccine study by patient age, adjusting for sampling factors.ResultsA total of 676 precancers (328 prevaccine and 348 postvaccine) and 1140 invasive cervical cancers (777 prevaccine and 363 postvaccine) were typed. No differences were observed in HPV‐type prevalence by patient age between the 2 studies among precancers or invasive cancers.ConclusionsThe lack of reduction in vaccine‐type prevalence between the 2 studies is likely explained by the low number of cases and low HPV vaccination coverage among women in the postvaccine study. Monitoring HPV‐type prevalence through population‐based strategies will continue to be important in evaluating the impact of the HPV vaccine.

An Evaluation of Dose-Related HPV Vaccine Effectiveness Using Central Registries in Michigan

Abstract Background: Human papillomavirus (HPV) vaccine effectiveness (VE) evaluations provide important information for vaccination programs. We established a linkage between statewide central registries in Michigan to estimate HPV VE against in situ and invasive cervical lesions (CIN3+). Methods: We linked females in Michigan's immunization and cancer registries using birth records to establish a cohort of 773,193 women with known vaccination history, of whom 3,838 were diagnosed with CIN3+. Residential address histories from a stratified random sample were used to establish a subcohort of 1,374 women without CIN3+ and 2,900 with CIN3+ among continuous Michigan residents. VE and 95% confidence intervals (CI) were estimated using cohort and case–cohort methods for up-to-date (UTD) vaccination and incomplete vaccination with 1 and 2 doses, and stratified by age at vaccination. Results: Both analytic approaches demonstrated lower CIN3+ risk with UTD and non-UTD vaccination vs. no vaccination. The cohort analysis yielded VE estimates of 66% (95% CI, 60%–71%) for UTD, 33% (95% CI, 18%–46%) for 2 doses-not UTD, and 40% (95% CI, 27%–50%) for 1 dose. The case–cohort analysis yielded VE estimates of 72% (95% CI, 64%–79%) for UTD, 39% (95% CI, 10%–58%) for 2 doses-not UTD, and 48% (95% CI, 25%–63%) for 1 dose. VE was higher for vaccination at age <20 than ≥20 years. Conclusions: The statewide registry linkage found significant VE against CIN3+ with incomplete HPV vaccination, and an even higher VE with UTD vaccination. Impact: Future VE evaluations by number of doses for women vaccinated at younger ages may further clarify dose-related effectiveness.