Can clinical tests help monitor human papillomavirus vaccine impact?

Abstract

As immunization programs for human papillomavirus (HPV) are implemented more widely around the world, interest is increasing in measuring their impact. One early measurable impact of HPV vaccine is on the prevalence of specific HPV types in a population. In low-resource settings, a potentially attractive strategy would be to monitor HPV prevalence using clinical cervical cancer screening test results to triage specimens for HPV typing. We assessed this approach in a nationally representative population of U.S. females aged 14-59 years. Using self-collected cervico-vaginal swab specimens from 4,150 women participating in the National Health and Nutrition Examination Survey during 2003-2006, we evaluated type-specific HPV prevalence detected by the Roche linear array (LA) research test on all specimens, compared with type-specific HPV prevalence detected by LA conducted only on specimens positive by the digene hybrid capture 2 (HC-2) clinical test. We calculated weighted prevalence estimates and their 95% confidence intervals (CIs), and examined relative type-specific HPV prevalence according to the two testing approaches. The population prevalence of oncogenic HPV vaccine types 16/18 was 6.2% (CI:5.4-7.1) by LA if all specimens were tested, and 2.4% (CI:1.9-3.0) if restricted to positive HC-2. Relative prevalence of individual HPV types was similar for both approaches. Compared with typing all specimens, a triage approach would require testing fewer specimens, but a greater reduction in HPV prevalence or a larger group of specimens would be needed to detect vaccine impact. Further investigation is warranted to inform type-specific HPV monitoring approaches around the world.

Cross-reactivity profiles of hybrid capture II, cobas, and APTIMA human papillomavirus assays: split-sample study

“…There is no internationally agreed standard genotyping assay, so the choice of a reference assay can be discussed [ 7 , 11 ]. No HPV assay, with or without genotyping, seems to detect all targeted infections [ 17 , 23 ]. CLART is a CE-IVD marked assay, not “research use only”, and is currently used in a number of regional European screening programmes.…”

Comparison of the performance of Anyplex II HPV HR, the Cobas 4800 human papillomavirus test and Hybrid Capture 2

“…Single genotyping is important to predict the impact of vaccination on genotype distribution. 16,17 A reduction in the prevalence of HPV16/18 from 19.1% to 6.5% was observed in sexually active young women after the introduction of HPV immunization. 18 The use of HPV genotyping tests is recommended in order to predict the potential severity of a precancerous state with abnormal cytology, even if the patient is a young woman.…”

Exploring monitoring strategies for population surveillance of HPV vaccine impact using primary HPV screening

“…However, a comparison of prevalence estimates for population surveillance using cervical screening samples has not been previously assessed. In a national US study, type-specific HPV prevalence by LA was compared to type-specific prevalence by LA on samples that first tested positive with the Digene Hybrid Capture 2 (HC-2) clinical test [ 9 ]. The relative prevalence of individual HPV types was reported to be similar for both approaches, but absolute prevalence estimates varied widely [HPV16/18 prevalence: 6.2% (LA) vs 2.4% (HC-2/LA); oncogenic HPV: 23.7% (LA) vs 7.3% (HC-2/LA)].…”

“…Most regulatory-approved assays for clinical use distinguish between a small number of individual oncogenic HPV types, while generating a pooled result for other oncotypes. In contrast, assays used in epidemiological studies detect individual oncogenic and non-oncogenic (‘low risk types’) HPV types with higher analytic sensitivity [ 9 ]. HPV-based cervical screening now offers the potential for routinely collected high-volume data for monitoring the impact of HPV vaccination, with the major caveat being that HPV detection for screening purposes doesn't aim to detect all HPV present, only oncogenic HPV at levels correlated with the presence of disease.…”