Epidemiologic approaches to evaluating the potential for human papillomavirus type replacement postvaccination

Pattern of multiple human papillomavirus infection and type competition: An analysis in healthy Chinese women aged 18-45 years

To assess the pattern of multiple human papillomavirus infection to predict the type replacement postvaccination. A total of 7372 women aged 18-45y from a phase III trial of an Escherichia coli-produced HPV-16/18 vaccine were analyzed at enrollment visit before vaccination. Hierarchical multilevel logistic regression was used to evaluate HPV vaccine type and nonvaccine-type interactions with age as a covariate. Binary logistic regression was construed to compare multiple infections with single infections to explore the impact of multiple-type infections on the risk of cervical disease. Multiple HPV infections were observed in 25.2% of HPV-positive women and multiple infections were higher than expected by chance. Statistically significant negative associations were observed between HPV16 and 52, HPV18 and HPV51/52/58, HPV31 and HPV39/51/52/53/54/58, HPV33 and HPV52/58, HPV58 and HPV52, HPV6 and HPV 39/51/52/53/54/56/58. Multiple HPV infections increased the risk of CIN2+ and HSIL+, with the ORs of 2.27(95%CI: 1.41, 3.64) and 2.26 (95%CI: 1.29, 3.95) for multiple oncogenic HPV infection separately. However, no significant evidence for the type-type interactions on risk of CIN2+ or HSIL+. There is possibility of type replacement between several pairs of vaccine and nonvaccine HPV type. Multiple HPV infection increased the risk of cervical disease, but coinfection HPV types seem to follow independent disease processes. Continued post-vaccination surveillance for HPV 51/52/58 types and HPV 39/51 types separately was essential after the first and second generation of HPV vaccination implementation in China.

Predictable changes in the accuracy of human papillomavirus tests after vaccination: review with implications for performance monitoring in cervical screening

Vaccination against human papillomavirus (HPV) is changing the performance of cytology as a cervical screening test, but its effect on HPV testing is unclear. We review the effect of HPV16/18 vaccination on the epidemiology and the detection of HPV infections and high-grade cervical lesions (CIN2+) to evaluate the likely direction of changes in HPV test accuracy. The reduction in HPV16/18 infections and cross-protection against certain non-16/18 high-risk genotypes, most notably 31, 33, and/or 45, will likely increase the test's specificity but decrease its positive predictive value (PPV) for CIN2+. Post-vaccination viral unmasking of non-16/18 genotypes due to fewer HPV16 co-infections might reduce the specificity and the PPV for CIN2+. Post-vaccination clinical unmasking exposing a higher frequency of CIN2+ related to non-16/18 high-risk genotypes is likely to increase the specificity and the PPV of HPV tests. The effect of HPV16/18 vaccination on HPV test sensitivity is difficult to predict based on these changes alone. Programmes relying on HPV detection for primary screening should monitor the frequency of false-positive and false-negative tests in vaccinated (younger) vs. unvaccinated (older) cohorts, to assess the outcomes and performance of their service.

Genital and Oral HPV Geno-Prevalence Measured through Urine and Saliva Samples in Young Adults in Italy

BACKGROUND

The aims of the study were to determine, in the urine and oral samples of young adults, the genotype-specific prevalence of Human Papilloma Virus (HPV) infection, the HPV DNA type-specific prevalence in unvaccinated and vaccinated individuals, and the determinants of HPV infection.

METHODS

Selected participants were asked to fill in a self-administered questionnaire and to self-collect urine and saliva samples.

RESULTS

Among the 1002 participants, 81 (8.1%) resulted positive for HPV DNA. The most common low-risk genotype was HPV 42 (2.2%), followed by HPV 43 (0.8%), and 40 (0.5%). The HPV 51 was the most common high-risk genotype (1.5%) followed by HPV 66 (1%) and HPV 68 (1%), and no participants were infected with HPV genotypes 18, 33, 45. Females, those who have had one or more occasional sexual partner, those who never/rarely/sometimes used condoms during their sexual activity, those with a previous diagnosis of sexually transmitted infection, and those who were not vaccinated were more likely to be tested positive for HPV infection.

CONCLUSIONS

The low prevalence of genital HPV infections has provided evidence of the effectiveness of HPV vaccination both in vaccinated and not yet vaccinated subjects through herd immunity and indicated its decisive role in the changing epidemiology of circulating HPV genotypes in the population.

Betapapillomavirus natural history and co-detection with alphapapillomavirus in cervical samples of adult women

Human papillomaviruses (HPV) of the genus Betapapillomavirus can infect both cutaneous and mucosal sites, but research on their natural history at mucosal sites remains scarce. We examined the risk factors and co-detection patterns of HPVs of the Betapapillomavirus and Alphapapillomavirus genera in cervical samples of the Ludwig-McGill cohort study. We assessed a subset of 505 women from the Ludwig-McGill cohort study from São Paulo, Brazil. Cervical samples over the first year of follow-up were tested for DNA of over 40 alphapapillomavirus types and 43 betapapillomavirus types using a type-specific multiplex genotyping polymerase chain reaction assay. We assessed the risk factors for prevalent and incident betapapillomavirus type detection, and whether types were detected more frequently together than expected assuming independence using permutation tests, logistic regression, and Cox regression. We observed significant within-genus clustering but not cross-genus clustering. Multiple betapapillomavirus types were co-detected in the same sample 2.24 (95% confidence interval [CI]: 1.65-3.29) times more frequently than expected. Conversely, co-detections of alphapapillomavirus and betapapillomavirus types in the same sample occurred only 0.64 (95% CI: 0.51-0.83) times as often as expected under independence. In prospective analyses, positivity to one HPV genus was associated with a nonsignificant lower incidence of detection of types in the other genus. Lifetime number of sex partners and new sex partner acquisition were associated with lower risks of prevalent and incident betapapillomavirus detection. Betapapillomaviruses are commonly found in the cervicovaginal tract. Results suggest potentially different mechanisms of transmission for betapapillomavirus genital infections other than vaginal sex.

Protocol: carrageenan for the prevention of oral HPV infection - a feasibility randomised clinical trial

INTRODUCTION

Head and neck cancers (HNCs) are a significant health burden worldwide. Oral human papillomavirus (HPV) infection is a major risk factor for HNCs. Unfortunately, currently available prophylactic vaccines have limited coverage and potential for HPV type replacement. Carrageenan, a natural product extracted from marine red algae, has demonstrated potency as an HPV inhibitor and could offer a potential alternative to prevent HPV-related diseases, including oral HPV infection. However, there is a lack of clinical studies on the effect of carrageenan on oral HPV infections. As a first step to address this gap, we propose a randomised controlled trial (RCT) to evaluate the feasibility of conducting a larger multicentric RCT to investigate the effect of a carrageenan mouthwash on oral HPV infection.

METHODS AND ANALYSIS

We will conduct a placebo-controlled triple-blinded feasibility RCT with two parallel arms, each arm consisting of 20 participants. Participants will complete a single in-person visit at baseline and conduct biweekly follow-ups from home by completing a web-based questionnaire and sending saliva self-samples via mail. During the 6-month period trial, participants will gargle with the mouthwash morning and night, and around sexual activities. The study will evaluate several factors including recruitment and retention rates, the feasibility of data collection procedures, compliance with study procedures, acceptability of RCT procedures and intervention and safety data on carrageenan use in the oral cavity. We will estimate the standard deviation of outcome measures, including time to the incidence of oral HPV infection and time to clearance of prevalent oral HPV infection. The trial primary outcome is whether to proceed to a definitive trial based on prespecified progression criteria.

ETHICS AND DISSEMINATION

The protocol was approved by the McGill University institutional review board. Study results will be presented at scientific conferences and published in academic journals.

TRIAL REGISTRATION NUMBER

NCT05746988.

Analysis of publications on HPV genotype co-infection: a bibliometric study on existing research

PURPOSE

To identify the bibliometric information of Human papillomavirus (HPV) genotype co-infection in certain literature database over the past two decades.

METHODS

Web of Science was used as the main database to identify all eligible articles focusing on HPV genotype co-infection at the date of October 16, 2022. From this journal database, we identified 463 articles on HPV genotype co-infection, conducted statistical analysis according to the author, journal, publication year and month, country or region, keyword and impact factor.

RESULTS

The articles included in our analysis were published between 1994 and 2022. The index of citations per year ranged from 170.4 to 13.1. These articles were from 78 countries or regions, with most publications from the United States (n = 73), followed by China (n = 65) and Italy (n = 50). The journal that contributed the most publications on HPV heterotypic gene co-infection was PLOS ONE with a total of 29 articles, followed by JOURNAL OF MEDICAL VIROLOGY (n = 28), INFECTIOUS AGENTS AND CANCER (n = 14) and JOURNAL OF CLINICAL VIROLOGY (n = 12). Among existing research in the field of HPV co-infection, we found that epidemiological distribution and infection mechanism has been the two major topics for scholars, and studies on detection methods for HPV multiple genotypes were also included.

CONCLUSION

Over decades, epidemiological studies and mechanism investigationhas been the central topics when it comes to HPV genotypes co-infection. Studies on HPV co-infection remained relatively insufficient, mainly stays in qualitative level while detailed infection data and high quality literature publications were still lack of valuable discussion.

Implications of viral infections and oncogenesis in uterine cervical carcinoma etiology and pathogenesis

Background

Uterine Cervical Carcinoma (UCC) is the most prevalent gynecological malignancy globally, with a rising incidence in recent years. Accumulating evidence indicates that specific viral infections, including human papillomavirus (HPV), Epstein-Barr virus (EBV), Hepatitis B and C viruses (HBV and HCV), and human herpesvirus (HHV), may contribute to UCC development and progression. Understanding the complex interplay between viral infections and UCC risk is crucial for developing novel preventative and therapeutic interventions.

Methods

This comprehensive review investigates the association between viral infections and UCC risk by examining the roles of various viral pathogens in UCC etiology and pathogenesis, and possible molecular mechanisms. Additionally, we evaluate current diagnostic methods and potential therapeutic strategies targeting viral infections for UCC prevention or treatment.

Results

The prevention of UCC has been significantly advanced by the emergence of self-sampling for HPV testing as a crucial tool, allowing for early detection and intervention. However, an essential challenge in UCC prevention lies in understanding how HPV and other viral coinfections, including EBV, HBV, HCV, HHV, HIV, or their concurrent presence, may potentially contribute to UCC development. The molecular mechanisms implicated in the association between viral infections and cervical cancer development include: (1) interference of viral oncogenes with cellular regulatory proteins, resulting in uncontrolled cell proliferation and malignant transformation; (2) inactivation of tumor suppressor genes by viral proteins; (3) evasion of host immune responses by viruses; (4) induction of a persistent inflammatory response, contributing to a tumor-promoting microenvironment; (5) epigenetic modifications that lead to aberrant gene expression; (6) stimulation of angiogenesis by viruses; and (7) activation of telomerase by viral proteins, leading to cellular immortalization. Additionally, viral coinfections can also enhance oncogenic potential through synergistic interactions between viral oncoproteins, employ immune evasion strategies, contribute to chronic inflammation, modulate host cellular signaling pathways, and induce epigenetic alterations, ultimately leading to cervical carcinogenesis.

Conclusion

Recognizing the implications of viral oncogenes in UCC etiology and pathogenesis is vital for addressing the escalating burden of UCC. Developing innovative preventative and therapeutic interventions requires a thorough understanding of the intricate relationship between viral infections and UCC risk.

Evolution of human papilloma virus prevalence in a highly vaccinated region in Belgium: a retrospective cohort study in Flemish women (2010-2019)

OBJECTIVE

In order to lower the incidence of cervical cancer, vaccines against high-risk types of the human papilloma virus (hrHPV) were approved and brought on the market in 2007, with a partial reimbursement for Belgian citizens younger than 18 years old. Since 2010, a school-based vaccination program ensures a high vaccination coverage in young women. In this study, the impact of the Belgian vaccination program on the prevalence of HPV 16/18 is studied, together with the evolution of the prevalence of other hrHPV types and precancerous lesions.

METHODS

Results of HPV typing and cytology in papanicolaou-smears from women aged 20-23 years taken between 2010 and 2019 were used. An older, nonvaccinated group of women of 40-45 years old served as a control group.

RESULTS

A significant decrease in prevalence of HPV types 16 and 18 was found in the 20-23-years-old women, whereas no decrease was found in the age group 40-45. Alongside this decrease, a significant decrease in prevalence of subtypes 6, 11 and 31 was observed, whereas type 31 is not included in the administered vaccines. Remarkably, there was no decrease in prevalence of cytological abnormalities in the study group during this study. There was even an increase in prevalence of high-risk types 53, 58 and 67.

CONCLUSION

These findings emphasise the need to maintain the screening programs, even in areas with high vaccination coverage.

High Prevalence of HPV 51 in an Unvaccinated Population and Implications for HPV Vaccines

Human papillomavirus (HPV) is detected in 99.7% of cervical cancers. Current vaccines target types 16 and 18. Prior to vaccination implementation, a prospective cohort study was conducted to determine baseline HPV prevalence in unvaccinated women in Wales; after HPV16 and HPV18, HPV 51 was found to be most prevalent. This study aimed to re-assess the unexpected high prevalence of HPV 51 and consider its potential for type-replacement. Two hundred HPV 51 positive samples underwent re-analysis by repeating the original methodology using HPV 51 GP5+/6+ PCR-enzyme immunoassay, and additionally a novel assay of HPV 51 E7 PCR. Data were correlated with age, social deprivation and cytology. Direct repeat of HPV 51 PCR-EIA identified 146/195 (75.0%) samples as HPV 51 positive; E7 PCR identified 166/195 (85.1%) samples as HPV 51 positive. HPV 51 prevalence increased with cytological grade. The prevalence of HPV 51 in the pre-vaccinated population was truly high. E7 DNA assays may offer increased specificity for HPV genotyping. Cross-protection of current vaccines against less-prevalent HPV types warrants further study. This study highlights the need for longitudinal investigation into the prevalence of non-vaccine HPV types, especially those phylogenetically different to vaccine types for potential type-replacement. Ongoing surveillance will inform future vaccines.

Precancerous cervical lesions caused by non-vaccine-preventable HPV types after vaccination with the bivalent AS04-adjuvanted HPV vaccine: an analysis of the long-term follow-up study from the randomised Costa Rica HPV Vaccine Trial

BACKGROUND

In women vaccinated against human papillomavirus (HPV), reductions in cervical disease and related procedures results in more women having intact transformation zones, potentially increasing the risk of cervical lesions caused by non-vaccine-preventable HPV types, a phenomenon termed clinical unmasking. We aimed to evaluate HPV vaccine efficacy against cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and cervical intraepithelial neoplasia grade 3 or worse (CIN3+) attributed to non-preventable HPV types in the long-term follow-up phase of the Costa Rica HPV Vaccine Trial (CVT).

METHODS

CVT was a randomised, double-blind, community-based trial done in Costa Rica. Eligible participants were women aged 18-25 years who were in general good health. Participants were randomly assigned (1:1) to receive an HPV 16 and 18 AS04-adjuvanted vaccine or control hepatitis A vaccine, using a blocked randomisation method (permuted block sizes of 14, 16, and 18). Vaccines in both groups were administered intramuscularly with 0·5 mL doses at 0, 1, and 6 months. Masking of vaccine allocation was maintained throughout the 4-year randomised trial phase, after which participants in the hepatitis A virus vaccine control group were provided the HPV vaccine and exited the study; a screening-only, unvaccinated control group was enrolled. The unvaccinated control group and HPV vaccine group were followed up for 7 years, during which treatment allocation was not masked. One of the prespecified primary endpoints for the long-term follow-up phase was precancers associated with HPV types not prevented by the vaccine, defined as histologically confirmed incident CIN2+ events or CIN3+ events attributed to any HPV type except HPV 16, 18, 31, 33, and 45. Our primary analytical period was years 7-11. Primary analyses were in all participants with at least one follow-up visit and excluded participants with a previous endpoint (ie, modified intention-to-treat cohort). Safety endpoints have been reported elsewhere. This trial is registered with ClinicalTrials.gov, NCT00128661 and NCT00867464. The randomised, masked trial phase is completed; an unmasked subset of women in the HPV-vaccinated group is under active investigation.

FINDINGS

Between June 28, 2004, and Dec 21, 2005, 7466 participants were enrolled (HPV vaccine group n=3727 and hepatitis A virus vaccine control group n=3739). Between March 30, 2009, and July 5, 2012, 2836 women enrolled in the new unvaccinated control group. The primary analytical cohort (years 7 to 11) included 2767 participants in the HPV vaccine group and 2563 in the unvaccinated group for the CIN2+ events endpoint assessment and 2826 participants in the HPV vaccine group and 2592 in the unvaccinated control group for the CIN3+ events endpoint assessment. Median follow-up during years 7 to 11 for women included for the CIN2+ events analysis was 52·8 months (IQR 44·0 to 60·7) for the HPV vaccine group and 49·8 months (42·0 to 56·9) for the unvaccinated control group. During years 7 to 11, clinical unmasking was observed with a negative vaccine efficacy against CIN2+ events attributed to non-preventable HPV types (-71·2% [95% CI -164·0 to -12·5]), with 9·2 (95% CI 2·1 to 15·6) additional CIN2+ events attributed to non-preventable HPV types per 1000 HPV-vaccinated participants versus HPV-unvaccinated participants. 27·0 (95% CI 14·2 to 39·9) fewer CIN2+ events irrespective of HPV type per 1000 vaccinated participants were observed during 11 years of follow-up. Vaccine efficacy against CIN3+ events attributed to non-preventable HPV types during years 7 to 11 was -135·0% (95% CI -329·8 to -33·5), with 8·3 (3·0 to 12·8) additional CIN3+ events attributed to non-preventable HPV types per 1000 vaccinated participants versus unvaccinated participants.

INTERPRETATION

Higher rates of CIN2+ events and CIN3+ events due to non-preventable HPV types in vaccinated versus unvaccinated participants suggests clinical unmasking could attenuate long-term reductions in high-grade disease following successful implementation of HPV vaccination programmes in screened populations. Importantly, the net benefit of vaccination remains considerable; therefore, HPV vaccination should still be prioritised as primary prevention for cervical cancer.

FUNDING

National Cancer Institute and National Institutes of Health Office of Research on Women's Health.

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Population Impact of Girls-Only Human Papillomavirus 16/18 Vaccination in The Netherlands: Cross-Protective and Second-Order Herd Effects

Background

Human papillomavirus (HPV) vaccination programs achieve substantial population-level impact, with effects extending beyond protection of vaccinated individuals. We assessed trends in HPV prevalence up to 8 years postvaccination among men and women in the Netherlands, where bivalent HPV vaccination, targeting HPV types 16/18, has been offered to (pre)adolescent girls since 2009 with moderate vaccination coverage.

Methods

We used data from the PASSYON study, a survey initiated in 2009 (prevaccination) and repeated biennially among 16- to 24-year-old visitors of sexual health centers. We studied genital HPV positivity from 2009 to 2017 among women, heterosexual men, and unvaccinated women using Poisson generalized estimating equation models, adjusted for individual- and population-level confounders. Trends were studied for 25 HPV types detected by the SPF10-LiPA25 platform.

Results

A total of 6354 women (64.7% self-reported unvaccinated) and 2414 heterosexual men were included. Percentual declines in vaccine types HPV-16/18 were observed for all women (12.6% per year [95% confidence interval {CI}, 10.6–14.5]), heterosexual men (13.0% per year [95% CI, 8.3–17.5]), and unvaccinated women (5.4% per year [95% CI, 2.9–7.8]). We observed significant declines in HPV-31 (all women and heterosexual men), HPV-45 (all women), and in all high-risk HPV types pooled (all women and heterosexual men). Significant increases were observed for HPV-56 (all women) and HPV-52 (unvaccinated women).

Conclusions

Our results provide evidence for first-order herd effects among heterosexual men against HPV-16/18 and cross-protective types. Additionally, we show second-order herd effects against vaccine types among unvaccinated women. These results are promising regarding population-level and clinical impact of girls-only bivalent HPV vaccination in a country with moderate vaccine uptake.

Prevalence of cervicovaginal human papillomavirus infection and genotypes in the pre-vaccine era in China: A nationwide population-based study

OBJECTIVE

The HPV vaccine has been licensed in mainland China since 2017. This study aimed to assess the epidemiological characteristics of HPV genotypes in the pre-vaccine era in China.

METHODS

We conducted a multicentric population-based study nested in the largest health clinic chain in China. Between January 1, 2017 and December 31, 2017, 427,401women aged 20 years or older with polymerase chain reaction-based HPV genotyping tests were included in the study. The cervicovaginal infection of 14 high-risk HPV genotypes and 9 low-risk genotypes was assessed using adjusted prevalence, multivariable logistic regression, cluster analysis, and heatmap.

RESULTS

HPV prevalence was 15.0% (95% confidence interval [CI]: 14.1-15.9%) in China, with high- and low-risk genotypes being 12.1% (95%CI: 11.4-12.7%) and 5.2% (95%CI: 4.8-5.7%), respectively. The prevalence of HPV genotypes corresponding to bivalent, quadrivalent, and nonavalent vaccines were 2.1%, 2.4%, and 8.3%, respectively, whereas the prevalence of non-vaccine high-risk genotypes was 5.7%. The most common high-risk genotypes were HPV-52 (3.5%), HPV-58 (2.1%), and HPV-16 (1.6%), and the prevalence of HPV-18 (0.6%), HPV-6 (0.1%), and HPV-11 (0.2%) were relatively low. Infection with HPV genotypes differed significantly across age groups and geographic locations.

CONCLUSION

HPV prevalence was high in the pre-vaccine era in China, and a population-based HPV vaccination strategy is needed in the future.

NanoString Technology for Human Papillomavirus Typing

High-throughput HPV typing assays with increased automation, faster turnaround and type-specific digital readout would facilitate studies monitoring the impact of HPV vaccination. We evaluated the NanoString nCounter^® platform for detection and digital readout of 48 HPV types in a single reaction. NanoString (NS) used proprietary software to design CodeSets: type-specific probe pairs targeting 48 HPV types and the globin gene. We tested residual DNA extracts from epidemiologic specimens and defined samples (HPV plasmids at 10 to 10⁴ copies/reaction) directly (No-PCR) as well as after L1 consensus PCR of 45 (PCR-45) or 15 cycles (PCR-15). Assay and interpretation followed NS recommendations. We evaluated analytic performance by comparing NanoString results for types included in prior assays: Roche Linear Array (LA) or HPV TypeSeq assay. No-PCR results on 40 samples showed good type-specific agreement with LA (k = 0.621) but sensitivity was 65% with lower limit of detection (LOD) at 10⁴ plasmid copies. PCR-45 results showed almost perfect type-specific agreement with LA (k = 0.862), 82% sensitivity and LOD at 10 copies. PCR-15 results on 75 samples showed substantial type-specific agreement with LA (k = 0.796, 92% sensitivity) and TypeSeq (k = 0.777, 87% sensitivity), and LOD at 10 copies of plasmids. This proof-of-principle study demonstrates the efficacy of the NS platform with HPV CodeSet for type-specific detection using a low number of PCR cycles (PCR-15). Studies are in progress to evaluate assay reproducibility and analytic validation with a larger number of samples.

Concurrent infection with multiple human papillomavirus types among unvaccinated and vaccinated 17-year-old Norwegian girls

Background

Whether type-specific human papillomavirus (HPV) infection influences the risk of acquiring infections with other HPV types is unclear. We studied concurrent HPV infections in 17-year-old girls from 2 birth cohorts; the first vaccine-eligible cohort in Norway and a prevaccination cohort.

Methods

Urine samples were collected and tested for 37 HPV genotypes. This study was restricted to unvaccinated girls from the prevaccination cohort (n = 5245) and vaccinated girls from the vaccine-eligible cohort (n = 4904). Risk of HPV infection was modelled using mixed-effect logistic regression. Expected frequencies of concurrent infection with each pairwise combination of the vaccine types and high-risk types (6/11/16/18/31/33/35/39/45/51/52/56/58/59) were compared to observed frequencies.

Results

Infection with multiple HPV types was more common among unvaccinated girls than vaccinated girls (9.2% vs 3.7%). HPV33 and HPV51 was the only HPV pair that was detected together more often than expected among both unvaccinated (P = .002) and vaccinated girls (P < .001). No HPV pairs were observed significantly less often than expected.

Conclusions

HPV33 and HPV51 tended to be involved in coinfection among both unvaccinated and vaccinated girls. The introduction of HPV vaccination does not seem to have had an effect on the tendency of specific HPV types to cluster together.

HPV cervical infections and serological status in vaccinated and unvaccinated women

Understanding genital infections by Human papillomaviruses (HPVs) remains a major public health issue, especially in countries where vaccine uptake is low. We investigate HPV prevalence and antibody status in 150 women (ages 18 to 25) in Montpellier, France. At inclusion and one month later, cervical swabs, blood samples and questionnaires (for demographics and behavioural variables) were collected. Oncogenic, non-vaccine genotypes HPV51, HPV66, HPV53, and HPV52 were the most frequently detected viral genotypes overall. Vaccination status, which was well-balanced in the cohort, showed the strongest (protective) effect against HPV infections, with an associated odds ratio for alphapapillomavirus detection of 0.45 (95% confidence interval: [0.22;0.58]). We also identified significant effects of age, number of partners, body mass index, and contraception status on HPV detection and on coinfections. Type-specific IgG serological status was also largely explained by the vaccination status. IgM seropositivity was best explained by HPV detection at inclusion only. Finally, we identify a strong significant effect of vaccination on genotype prevalence, with a striking under-representation of HPV51 in vaccinated women. Variations in HPV prevalence correlate with key demographic and behavioural variables. The cross-protective effect of the vaccine against HPV51 merits further investigation.

Efficacy of the AS04-Adjuvanted HPV16/18 Vaccine: Pooled Analysis of the Costa Rica Vaccine and PATRICIA Randomized Controlled Trials

BACKGROUND

The AS04-adjuvanted HPV16/18 (AS04-HPV16/18) vaccine provides excellent protection against targeted human papillomavirus (HPV) types and a variable degree of cross-protection against others, including types 6/11/31/33/45. High efficacy against any cervical intraepithelial neoplasia grade 3 or greater (CIN3+; >90%) suggests that lower levels of protection may exist for a wide range of oncogenic HPV types, which is difficult to quantify in individual trials. Pooling individual-level data from two randomized controlled trials, we aimed to evaluate AS04-HPV16/18 vaccine efficacy against incident HPV infections and cervical abnormalities .

METHODS

Data were available from the Costa Rica Vaccine Trial (NCT00128661) and Papilloma Trial Against Cancer in Young Adults trial (NCT00122681), two large-scale, double-blind randomized controlled trials of the AS04-HPV16/18 vaccine. Primary analyses focused on disease-free women with no detectable cervicovaginal HPV at baseline.

RESULTS

A total of 12 550 women were included in our primary analyses (HPV arm = 6271, control arm = 6279). Incidence of 6-month persistent oncogenic and nononcogenic infections, excluding known and accepted protected types 6/11/16/18/31/33/45 (focusing on 34/35/39/40/42/43/44/51/52/53/54/56/58/59/66/68/73/70/74), was statistically significantly lower in the HPV arm than in the control arm (efficacy = 9.9%, 95% confidence interval [CI] = 1.7% to 17.4%). Statistically significant efficacy (P < .05) was observed for individual oncogenic types 16/18/31/33/45/52 and nononcogenic types 6/11/53/74. Efficacy against cervical abnormalities (all types) increased with severity, ranging from 27.7% (95% CI = 21.7% to 33.3%) to 58.7% (95% CI = 34.1% to 74.7%) for cytologic outcomes (low-grade squamous intraepithelial neoplasia lesion or greater, and high-grade squamous intraepithelial neoplasia lesion or greater, respectively) and 66.0% (95% CI = 54.4% to 74.9%) to 87.8% (95% CI = 71.1% to 95.7%) for histologic outcomes (CIN2+ and CIN3+, respectively). Comparing Costa Rica Vaccine Trial and Papilloma Trial Against Cancer in Young Adults results, there was no evidence of heterogeneity, except for type 51 (efficacy = -28.6% and 20.7%, respectively; two-sided P = .03).

CONCLUSIONS

The AS04-HPV16/18 vaccine provides some additional cross-protection beyond established protected types, which partially explains the high efficacy against CIN3+.

Human Papillomavirus Vaccines: An Updated Review

Human papillomavirus (HPV) vaccines, which were introduced in many countries in the past decade, have shown promising results in decreasing HPV infection and related diseases, such as warts and precancerous lesions. In this review, we present the updated information about current HPV vaccines, focusing on vaccine coverage and efficacy. In addition, pan-gender vaccination and current clinical trials are also discussed. Currently, more efforts should be put into increasing the vaccine’s coverage, especially in low- and middle-income countries. Provision of education on HPV and vaccination is one of the most important methods to achieve this. Vaccines that target HPV types not included in current vaccines are the next stage in vaccine development. In the future, all HPV-related cancers, such as head and neck cancer, and anal cancer, should be tracked and evaluated, especially in countries that have introduced pan-gender vaccination programs. Therapeutic vaccines, in combination with other cancer treatments, should continue to be investigated.

HPV Genotype Prevalence and Success of Vaccination to Prevent Cervical Cancer

BACKGROUND

Nearly 500,000 new cases of cervical cancer are estimated annually worldwide. Three vaccines are currently licensed to prevent cervical cancer. The success of vaccination depends mainly on the prevalence of HPV genotypes, and many cases of HPV infection have been diagnosed after vaccination. Our aim was to search for HPV genotyping in cervical samples to verify the proportion of women that remain susceptible to infection even after vaccination.

METHODS

21,017 liquid-based cervical (LBC) specimens were received for cytology and HPV detection from 2015 to 2018. Before slide preparations for cytology, a 1,000-μL aliquot was taken from the LBC fixative and subjected to automated DNA extraction and multiplex PCR followed by capillary electrophoresis to detect and classify HPV.

RESULTS

HPV was detected in 895 (4.3%) specimens. The most prevalent genotype was HPV-16, followed by HPV-58 and HPV-66. A total of 258 (28.8%) cases were positive for high-risk (HR)-HPV types (66, 59, 39, 56, 30, 35, 53, 51, 68, 82, and 70) that are not covered by the HPV vaccines.

CONCLUSION

A significant proportion of HPV types detected in cytological specimens are representative of HR-HPV not covered by the available vaccines. The health system should be aware of the considerable percentage of women who are not being immunized and will continue to need cervical cancer screening.

Capturing multiple-type interactions into practical predictors of type replacement following human papillomavirus vaccination

Current HPV vaccines target a subset of the oncogenic human papillomavirus (HPV) types. If HPV types compete during infection, vaccination may trigger replacement by the non-targeted types. Existing approaches to assess the risk of type replacement have focused on detecting competitive interactions between pairs of vaccine and non-vaccine types. However, methods to translate any inferred pairwise interactions into predictors of replacement have been lacking. In this paper, we develop practical predictors of type replacement in a multi-type setting, readily estimable from pre-vaccination longitudinal or cross-sectional prevalence data. The predictors we propose for replacement by individual non-targeted types take the form of weighted cross-hazard ratios of acquisition versus clearance, or aggregate odds ratios of coinfection with the vaccine types. We elucidate how the hazard-based predictors incorporate potentially heterogeneous direct and indirect type interactions by appropriately weighting type-specific hazards and show when they are equivalent to the odds-based predictors. Additionally, pooling type-specific predictors proves to be useful for predicting increase in the overall non-vaccine-type prevalence. Using simulations, we demonstrate good performance of the predictors under different interaction structures. We discuss potential applications and limitations of the proposed methodology in predicting type replacement, as compared to existing approaches. This article is part of the theme issue 'Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses'.

Identification of HPV genotypes causing cervical precancer using tissue-based genotyping

Identification of high-risk human papillomavirus genotypes causing cervical precancer is crucial for informing HPV vaccine development and efficacy studies, and for determining which types to include in next-generation genotyping assays. Co-occurrence of hrHPV infections is common and complicates carcinogenicity assessment; accurate attribution requires tissue-based genotyping of precancers. We included all women with cervical intraepithelial neoplasia Grade 2 or worse (CIN2+) from the Biopsy Study, an observational study of 690 women enrolled between 2009 and 2012 at the University of Oklahoma. Tissue-based genotyping, including whole tissue sections (WTS) and laser-capture microdissection (LCM), was performed on all precancers with multiple hrHPV infections detected in cytology, totaling over 1,800 HPV genotyping assays. Genotype attribution was compared to hierarchical and proportional hrHPV-type attribution models. Of 276 women with CIN2+, 122 (44.2%) had multiple hrHPV genotypes in cytology. Of 114 women with genotyping data, 94 had one or more hrHPV detected in tissue. Seventy-one women (75.5%) had a single causal hrHPV genotype, while 23 women had multiple hrHPV genotypes causing CIN2+. Ten women had multiple causal infections in a single biopsy, contrary to the previous notion that each lesion is caused by a single type only. While HPV16 was the predominant causal hrHPV genotype using all approaches, the hierarchical model overattributed HPV16, whereas other causal hrHPV genotypes, particularly HPV18 and HPV35, were underattributed. Understanding true causal genotypes is important for the evaluation of vaccine efficacy, to estimate the extent of unmasking, and for type-specific risk assessment in screening and management.

Prevalence of Human Papillomavirus (HPV) and Other Sexually Transmitted Infections (STIs) among Italian Women Referred for a Colposcopy

Sexually transmitted infections (STIs) represent a major cause of morbidity in women and men worldwide. Human Papillomavirus (HPV) infections are among the most prevalent STIs and persistent infections with high-risk HPV (hrHPV) genotypes can cause cervical dysplasia and invasive cervical cancer. The association of other STIs with HPV cervical infection and/or dysplasia has however not yet been fully elucidated. The aim of this study was to assess the prevalence of HPV and other STIs among women presenting with an abnormal cervical cytology. Cervical infections with 28 HPV genotypes and seven other sexually transmitted pathogens were evaluated in 177 women referred for a colposcopy after an abnormal Pap smear. Positivity for at least one hrHPV genotype was shown in 87% of women; HPV 16 was the most prevalent (25.0%), followed by HPV 31 and HPV 51. The overall positivity for other STIs was 49.2%, with Ureaplasma parvum being the most prevalent microrganism (39.0%). Co-infections between hrHPV and other STIs were demonstrated in 17.5% of women; no significant association was demonstrated between multiple infections and the colposcopy findings. This study provides new epidemiological data on the prevalence of cervical infections associated with HPV and seven other common sexually transmitted pathogens in a population of women presenting with an abnormal cervical cytology.

Untangling the dynamics of persistence and colonization in microbial communities

A central goal of community ecology is to infer biotic interactions from observed distributions of co-occurring species. Evidence for biotic interactions, however, can be obscured by shared environmental requirements, posing a challenge for statistical inference. Here, we introduce a dynamic statistical model, based on probit regression, that quantifies the effects of spatial and temporal covariance in longitudinal co-occurrence data. We separate the fixed pairwise effects of species occurrences on persistence and colonization rates, a potential signal of direct interactions, from latent pairwise correlations in occurrence, a potential signal of shared environmental responses. We first validate our modeling framework with several simulation studies. Then, we apply the approach to a pressing epidemiological question by examining how human papillomavirus (HPV) types coexist. Our results suggest that while HPV types respond similarly to common host traits, direct interactions are sparse and weak, so that HPV type diversity depends largely on shared environmental drivers. Our modeling approach is widely applicable to microbial communities and provides valuable insights that should lead to more directed hypothesis testing and mechanistic modeling.

Population-level impact and herd effects following the introduction of human papillomavirus vaccination programmes: updated systematic review and meta-analysis

BACKGROUND

More than 10 years have elapsed since human papillomavirus (HPV) vaccination was implemented. We did a systematic review and meta-analysis of the population-level impact of vaccinating girls and women against human papillomavirus on HPV infections, anogenital wart diagnoses, and cervical intraepithelial neoplasia grade 2+ (CIN2+) to summarise the most recent evidence about the effectiveness of HPV vaccines in real-world settings and to quantify the impact of multiple age-cohort vaccination.

METHODS

In this updated systematic review and meta-analysis, we used the same search strategy as in our previous paper. We searched MEDLINE and Embase for studies published between Feb 1, 2014, and Oct 11, 2018. Studies were eligible if they compared the frequency (prevalence or incidence) of at least one HPV-related endpoint (genital HPV infections, anogenital wart diagnoses, or histologically confirmed CIN2+) between pre-vaccination and post-vaccination periods among the general population and if they used the same population sources and recruitment methods before and after vaccination. Our primary assessment was the relative risk (RR) comparing the frequency (prevalence or incidence) of HPV-related endpoints between the pre-vaccination and post-vaccination periods. We stratified all analyses by sex, age, and years since introduction of HPV vaccination. We used random-effects models to estimate pooled relative risks.

FINDINGS

We identified 1702 potentially eligible articles for this systematic review and meta-analysis, and included 65 articles in 14 high-income countries: 23 for HPV infection, 29 for anogenital warts, and 13 for CIN2+. After 5-8 years of vaccination, the prevalence of HPV 16 and 18 decreased significantly by 83% (RR 0·17, 95% CI 0·11-0·25) among girls aged 13-19 years, and decreased significantly by 66% (RR 0·34, 95% CI 0·23-0·49) among women aged 20-24 years. The prevalence of HPV 31, 33, and 45 decreased significantly by 54% (RR 0·46, 95% CI 0·33-0·66) among girls aged 13-19 years. Anogenital wart diagnoses decreased significantly by 67% (RR 0·33, 95% CI 0·24-0·46) among girls aged 15-19 years, decreased significantly by 54% (RR 0·46, 95% CI 0.36-0.60) among women aged 20-24 years, and decreased significantly by 31% (RR 0·69, 95% CI 0·53-0·89) among women aged 25-29 years. Among boys aged 15-19 years anogenital wart diagnoses decreased significantly by 48% (RR 0·52, 95% CI 0·37-0·75) and among men aged 20-24 years they decreased significantly by 32% (RR 0·68, 95% CI 0·47-0·98). After 5-9 years of vaccination, CIN2+ decreased significantly by 51% (RR 0·49, 95% CI 0·42-0·58) among screened girls aged 15-19 years and decreased significantly by 31% (RR 0·69, 95% CI 0·57-0·84) among women aged 20-24 years.

INTERPRETATION

This updated systematic review and meta-analysis includes data from 60 million individuals and up to 8 years of post-vaccination follow-up. Our results show compelling evidence of the substantial impact of HPV vaccination programmes on HPV infections and CIN2+ among girls and women, and on anogenital warts diagnoses among girls, women, boys, and men. Additionally, programmes with multi-cohort vaccination and high vaccination coverage had a greater direct impact and herd effects.

FUNDING

WHO, Canadian Institutes of Health Research, Fonds de recherche du Québec - Santé.

Unusual prevalence of high-risk genotypes of human papillomavirus in a group of women with neoplastic lesions and cervical cancer from Central Mexico

Human papillomavirus has been identified as a main etiological agent in the development of cervical cancer. HPV 16 and 18 have been reported the most widely prevalent genotypes worldwide. We conducted a study analyzing the prevalence of high and low risk human papillomavirus viral types in the Mexican state of Aguascalientes and neighboring cities in the states of Jalisco and Zacatecas in central Mexico. Specific viral genotype was determined by a PCR and hybridization-based detection test. The presence of 37 high- and low-risk HPV genotypes was evaluated in 883 female participants. Of these, 350 presented low-grade squamous intraepithelial lesions (LGSIL), 176 presented high-grade squamous intraepithelial lesions (HGSIL), 107 suffered from cervical cancer and 250 women with negative cytological report for intraepithelial lesion or malignancy (NILM). HPV 51 was the most prevalent genotype, followed by HPV 16: overall prevalence of HPV 51, including single infections and co-infections was 31.2% in women with LGSIL, whereas prevalence of HPV 16 was 25.1%. Among women with HGSIL, HPV 51 prevalence was 47.2% and HPV 16 was 30.1%. Prevalence of HPV 51 in women with cervical cancer was 49.5% and type 16 was 33.6%. Between single and co-infections, most co-infections were not associated with later stages of the disease, except 51/16 and some others. HPV 51 showed a significant correlation with the progression of the disease (OR = 10.81 for LGSIL, 19.38 for HGSIL and 22.95 for ICC), and when analyzing all other genotypes, five different groups depending on their correlation with all lesion grades were determined. According to our findings, HPV genotype 51 has a higher prevalence than HPV 16 and 18 in the Mexican state of Aguascalientes and neighboring cities in the states of Jalisco and Zacatecas in Central Mexico.

Bivalent Vaccine Effectiveness Against Type-Specific HPV Positivity: Evidence for Cross-Protection Against Oncogenic Types Among Dutch STI Clinic Visitors

Background

Observational postmarketing studies are important to assess vaccine effectiveness (VE). We estimated VE from the bivalent human papillomavirus (HPV) vaccine against HPV positivity of vaccine and nonvaccine types in a high-risk population.

Methods

We included all vaccine-eligible women from the PASSYON study, a biennial cross-sectional survey in Dutch sexually transmitted infection clinics. Vaginal swabs were analyzed using a polymerase chain reaction-based assay (SPF10-LiPA25) able to detect the 12 high-risk HPV (hrHPV) types 16/18/31/33/35/39/45/51/52/56/58/59. We compared hrHPV positivity between self-reported vaccinated (≥1 dose) and unvaccinated women, and estimated VE by a logistic mixed model.

Results

We included 1087 women of which 53% were hrHPV positive and 60% reported to be vaccinated. The adjusted pooled VE against HPV-16/18 was 89.9% (81.7%-94.4%). Moreover, we calculated significant VE against nonvaccine types HPV-45 (91%), HPV-35 (57%), HPV-31 (50%), and HPV-52 (37%). Among women who were offered vaccination 5/6 years ago, we estimated similar VE against HPV-16/18 (92%) and all hrHPV types (35%) compared to women who were offered vaccination <5 years ago (83% and 33%, respectively).

Conclusion

We demonstrated high VE of the bivalent vaccine against HPV-16/18 and cross-protection against HPV-45/35/31/52. Protection against HPV-16/18 was sustained up to 6 years postvaccination.

Changes in Cervical Human Papillomavirus (HPV) Prevalence at a Youth Clinic in Stockholm, Sweden, a Decade After the Introduction of the HPV Vaccine

Aim: This study aimed to follow the impact of human papillomavirus (HPV) catch-up and vaccination on the very high cervical HPV-prevalence in women at a youth clinic in central Stockholm during the period 2008–2018.

Background: 2008–2010, cervical HPV-prevalence (69.5%) and HPV16 prevalence (34.7%) were high in non-vaccinated women at a youth clinic in Stockholm. 2013–2015, after the introduction of the quadrivalent-Gardasil® HPV-vaccine, HPV16 and HPV6 prevalence had decreased. Here, cervical HPV-prevalence was investigated 10 years after primary sampling.

Material and Methods: 2017–2018, 178 cervical swabs, from women aged 15–23 years old, were tested for 27 HPV types by a bead-based multiplex method. HPV-prevalence data were then related to vaccination status and age and compared to HPV-prevalence in 615 samples from 2008 to 2010 and 338 samples from 2013 to 2015 from the same clinic, and to HPV types in 143 cervical cancer cases during 2003–2008 in Stockholm.

Results: The proportion of vaccinated women increased from 10.7% (2008–2010) to 82.1% (2017–2018). The prevalence of all 27 HPVs, all high-risk HPVs (HR-HPVs) and the combined presence of the quadrivalent-Gardasil® types HPV16, 18, 6, and 11, was lower in vaccinated compared to unvaccinated women (67.4 vs. 93.3%, p = 0.0031, 60.1 vs. 86.7%, p = 0.0057 and 5.8 vs. 26.7%, p = 0.002, respectively). Furthermore, HPV16 prevalence in non-vaccinated women 2017–2018 was lower than that in 2008–2010 (16.7 and 34.7%, respectively, p = 0.0471) and similar trends were observed for HPV18 and 11. In both vaccinated and non-vaccinated women, the most common non-quadrivalent-Gardasil® vaccine HR-HPV types were HPV39, 51, 52, 56, and 59. Together they accounted for around 9.8% of cervical cancer cases in Stockholm during 2003–2008, and their prevalence tended to have increased during 2017–2018 compared to 2008–2010.

Conclusion: Quadrivalent-Gardasil® vaccination has decreased HPV-vaccine type prevalence significantly. However, non-vaccine HR-HPV types remain high in potentially high-risk women at a youth clinic in Stockholm.

Inferring Pathogen Type Interactions Using Cross-sectional Prevalence Data: Opportunities and Pitfalls for Predicting Type Replacement

BACKGROUND

Many multivalent vaccines target only a subset of all pathogenic types. If vaccine and nonvaccine types compete, vaccination may lead to type replacement. The plausibility of type replacement has been assessed using the odds ratio (OR) of co-infections in cross-sectional prevalence data, with OR > 1 being interpreted as low risk of type replacement. The usefulness of the OR as a predictor for type replacement is debated, as it lacks a theoretical justification, and there is no framework explaining under which assumptions the OR predicts type replacement.

METHODS

We investigate the values that the OR can take based on deterministic S usceptible- I infected- S usceptible and S usceptible- Infected- Recovered- S usceptible multitype transmission models. We consider different mechanisms of type interactions and explore parameter values ranging from synergistic to competitive interactions.

RESULTS

We find that OR > 1 might mask competition because of confounding due to unobserved common risk factors and cross-immunity, as indicated by earlier studies. We prove mathematically that unobserved common risk factors lead to an elevation of the OR, and present an intuitive explanation why cross-immunity increases the OR. We find that OR < 1 is predictive for type replacement in the absence of immunity. With immunity, OR < 1 remains predictive under biologically reasonable assumptions of unidirectional interactions during infection, and an absence of immunity-induced synergism.

CONCLUSIONS

Using the OR in cross-sectional data to predict type replacement is justified, but is only unambiguous under strict assumptions. An accurate prediction of type replacement requires pathogen-specific knowledge on common risk factors and cross-immunity.

Human Papillomavirus Vaccine Effectiveness and Herd Protection in Young Women

BACKGROUND

Clinical trials of the 4-valent human papillomavirus (HPV) vaccine demonstrate high efficacy, but surveillance studies are essential to examine the long-term impact of vaccine introduction on HPV prevalence in community settings. The aims of this study were to determine during the 11 years after vaccine introduction the prevalence of (1) vaccine-type HPV in adolescent and young adult women who were vaccinated (to assess vaccine effectiveness) and (2) vaccine-type HPV in women who were unvaccinated (to assess herd protection).

METHODS

Young women 13 to 26 years of age were recruited from hospital-based and community health clinics for 4 surveillance studies from 2006 to 2017. We determined the proportion of vaccinated and unvaccinated women who were positive for vaccine-type HPV across the studies, and the odds of positivity for vaccine-type HPV using logistic regression; all analyses were propensity score-adjusted to control for between-wave differences in participant characteristics.

RESULTS

Vaccination rates increased from 0% to 84.3% (97% of study participants received the 4-valent vaccine). Among women who were vaccinated, 4-valent vaccine-type HPV detection decreased from 35% to 6.7% (80.9% decline; odds ratio 0.13, 95% confidence interval 0.08 to 0.22). Among women who were unvaccinated, 4-valent vaccine-type HPV detection decreased from 32.4% to 19.4% (40% decline; odds ratio 0.50, 95% confidence interval 0.26 to 0.97). Estimated vaccine effectiveness was 90.6% in wave 3 and 80.1% in wave 4.

CONCLUSIONS

In this study in which trends in HPV in a US community >10 years after 4-valent HPV vaccine introduction and after 9-valent vaccine introduction were examined, we found evidence of vaccine effectiveness and herd protection. Further research is needed to examine trends in 9-valent vaccine-type HPV after higher rates of vaccination are achieved.

Does Male Circumcision Reduce Women's Risk of Sexually Transmitted Infections, Cervical Cancer, and Associated Conditions?

Background: Male circumcision (MC) is proven to substantially reduce men's risk of a number of sexually transmitted infections (STIs). We conducted a detailed systematic review of the scientific literature to determine the relationship between MC and risk of STIs and associated conditions in women. Methods: Database searches by "circumcision women" and "circumcision female" identified 68 relevant articles for inclusion. Examination of bibliographies of these yielded 14 further publications. Each was rated for quality using a conventional rating system. Results: Evaluation of the data from the studies retrieved showed that MC is associated with a reduced risk in women of being infected by oncogenic human papillomavirus (HPV) genotypes and of contracting cervical cancer. Data from randomized controlled trials and other studies has confirmed that partner MC reduces women's risk not only of oncogenic HPV, but as well Trichomonas vaginalis, bacterial vaginosis and possibly genital ulcer disease. For herpes simplex virus type 2, Chlamydia trachomatis, Treponema pallidum, human immunodeficiency virus and candidiasis, the evidence is mixed. Male partner MC did not reduce risk of gonorrhea, Mycoplasma genitalium, dysuria or vaginal discharge in women. Conclusion: MC reduces risk of oncogenic HPV genotypes, cervical cancer, T. vaginalis, bacterial vaginosis and possibly genital ulcer disease in women. The reduction in risk of these STIs and cervical cancer adds to the data supporting global efforts to deploy MC as a health-promoting and life-saving public health measure and supplements other STI prevention strategies.

Substantial Decline in Prevalence of Vaccine-Type and Nonvaccine-Type Human Papillomavirus (HPV) in Vaccinated and Unvaccinated Girls 5 Years After Implementing HPV Vaccine in Norway

Background

In 2009, quadrivalent human papillomavirus (HPV) vaccine was introduced in a school-based single-cohort program targeting 12-year-old girls in Norway. We estimated the impact of the Norwegian HPV immunization program.

Methods

Three birth cohorts of 17-year-old girls, 2 nonvaccine-eligible cohorts (born 1994 or 1996) and 1 vaccine-eligible cohort (born 1997) were invited to deliver urine samples. The samples were analyzed for 37 HPV genotypes. HPV prevalence was compared between birth cohorts and between vaccinated and unvaccinated girls within and across birth cohorts after linkage to the Norwegian Immunisation Registry.

Results

In total, 17749 urine samples were analyzed. A 42% (95% confidence interval [CI], 37%-47%) reduction in any HPV type and 81% (95% CI, 76%-85%) reduction in vaccine types (HPV-6/11/16/18) were observed in the vaccine-eligible cohort compared to the 1994 cohort. Vaccine types were reduced by 54% (95% CI, 39%-66%) and 90% (95% CI, 86%-92%) in unvaccinated and vaccinated girls, respectively, from the 1997 cohort, compared with unvaccinated girls born in 1994. A significant reduction was also observed for several nonvaccine types. Vaccine-type prevalence was reduced by 77% (95% CI, 65%-85%) in vaccinated compared with unvaccinated girls from the 1997 cohort.

Conclusions

In this largely HPV-naive population, we observed a substantial reduction in vaccine and nonvaccine types in vaccinated and unvaccinated girls following introduction of HPV vaccination.

Determining the HPV vaccine schedule for a HIV-infected population in sub Saharan Africa, a commentary

BACKGROUND

Epidemiological studies have established human papillomavirus (HPV) infection as the central cause of invasive cervical cancer (ICC) and its precursor lesions. HIV is associated with a higher prevalence and persistence of a broader range of high-risk HPV genotypes, which in turn results in a higher risk of cervical disease. Recent WHO HPV vaccination schedule recommendations, along with the roll out of HAART at an earlier CD4 count within the female HIV-infected population, may have programmatic implications for sub Saharan Africa. This communication identifies research areas, which will need to be addressed for determining a HPV vaccine schedule for this population in sub Saharan Africa. A review of WHO latest recommendations and the evidence concerning one-dose HPV vaccine schedules was undertaken.

CONCLUSION

For females ≥15 years at the time of first dose and immunocompromised and/or HIV-infected, a 3-dose schedule (0, 1-2, 6 months) is recommended for all three vaccines. There is some evidence that there is similar protection against HPV 16 and 18 infection from a single vaccination than from two or three doses, however there is no cross protection conferred to other genotypes. There is a need for periodic prevalence studies to determine the vaccination coverage of bivalent, quadrivalent and nonavalent vaccine targeted oncogenic HPV genotypes in women with CIN 3 or ICC at national level. In light of the increasing number of sub Saharan HIV-infected girls initiating HAART at a CD4 count above 350 mm3, there are a number of clinical, virological and public health research gaps to address before a tailored vaccine schedule can be established for this population.

Decline of HPV infections in Scandinavian cervical screening populations after introduction of HPV vaccination programs

OBJECTIVE

To monitor the changes in prevalence of human papillomavirus (HPV) infections in women <50 years of age, participating in cervical screening programs of Denmark, Norway, and Sweden, before and after introduction of quadrivalent HPV (qHPV) vaccination.

METHODS

Liquid-based cytology samples were collected from 6538 women who attended cervical screening in Denmark, Norway, and Sweden in 2006-2008 and from 6332 similarly enrolled women in 2012-2013. Denmark started organized qHPV vaccination in 2008, Norway in 2009, and Sweden in 2012. All HPV testing and genotyping was performed using identical enrollment and analysis methods, by accredited general primer polymerase chain reaction methods with typing using the Luminex system.

RESULTS

Overall HPV positivity declined slightly from 36.5% in 2006-2008 to 34.5% in 2012-2013. The decline was most pronounced among women 18-26 years of age: from 54.4% to 48.1% (P < 0.001). The decline was substantial for vaccine HPV types (HPV6/11/16/18: decline from 22.3% to 16.6%; P < 0.001) and was seen for both low-risk vaccine types (HPV6/11 declined from 5.0% to 2.5%) and high-risk vaccine types (HPV16/18 declined from 18.9% to 14.9%). Among women 27-50 years of age, there was no change between the time periods (22.5% and 21.6%, respectively). The significant decline in the younger age group was different in the 3 countries.

CONCLUSION

This population-based study enrolling >12,000 women participating in cervical screening in the 3 Nordic countries before and after introduction of organized qHPV vaccination demonstrated a marked decline in HPV infection in the younger population in the 2 countries where qHPV vaccination programs started in 2008-2009, suggesting that organized HPV vaccination programs resulted in a decrease of HPV types circulating in the general population.

Human papillomavirus vaccination and the role of herd effects in future cancer control planning: a review

INTRODUCTION

Vaccine herd effects are the indirect protection that vaccinated persons provide to those who remain susceptible to infection, due to the reduced transmission of infections. Herd effects have been an important part of the discourse on how to best implement human papillomavirus (HPV) vaccines and prevent HPV-related diseases.

AREAS COVERED

In this paper, we review the theory of HPV vaccine herd effects derived from mathematical models, give an account of observed HPV vaccine herd effects worldwide, and examine the implications of vaccine herd effects for future cervical cancer screening efforts.

EXPERT COMMENTARY

HPV vaccine herd effects improve the cost-effectiveness of vaccinating preadolescent girls, but contribute to making gender-neutral vaccination less economically efficient. Vaccination coverage and sexual mixing patterns by age are strong determinants of herd effects. Many countries worldwide are starting to observe reductions in HPV-related outcomes likely attributable to herd effects, most notably declining anogenital warts in young men, and declining HPV-16/18 infection prevalence in young unvaccinated women. Policy makers making recommendations for cervical cancer screening will have to consider HPV vaccination coverage and herd effects, as these will affect the positive predictive value of screening and the risk of cervical cancer in unvaccinated women.

Population-Level Effects of Human Papillomavirus Vaccination Programs on Infections with Nonvaccine Genotypes

We analyzed human papillomavirus (HPV) prevalences during prevaccination and postvaccination periods to consider possible changes in nonvaccine HPV genotypes after introduction of vaccines that confer protection against 2 high-risk types, HPV16 and HPV18. Our meta-analysis included 9 studies with data for 13,886 girls and women ≤19 years of age and 23,340 women 20-24 years of age. We found evidence of cross-protection for HPV31 among the younger age group after vaccine introduction but little evidence for reductions of HPV33 and HPV45. For the group this same age group, we also found slight increases in 2 nonvaccine high-risk HPV types (HPV39 and HPV52) and in 2 possible high-risk types (HPV53 and HPV73). However, results between age groups and vaccines used were inconsistent, and the increases had possible alternative explanations; consequently, these data provided no clear evidence for type replacement. Continued monitoring of these HPV genotypes is important.

Monitoring vaccine and non-vaccine HPV type prevalence in the post-vaccination era in women living in the Basilicata region, Italy

Background

A large free-of-charge quadrivalent HPV (qHPV) vaccination program, covering four cohorts annually (women 11, 14, 17 and 24 years), has been implemented in Basilicata since 2007. This study evaluated vaccine and non-vaccine HPV prevalence 5-7 years post-vaccination program implementation in vaccinated and unvaccinated women.

Methods

This population-based, cross-sectional study was conducted in the public screening centers of the Local Health Unit in Matera between 2012 and 2014. Cervical samples were obtained for Pap and HPV testing (HC2, LiPA Extra® assay) and participants completed a sociodemographic and behavioral questionnaire. Detailed HPV vaccination status was retrieved from the official HPV vaccine registry. HPV prevalence was described overall, by type and vaccination status. The association between HPV type-detection and risk/protective factors was studied. Direct vaccine protection (qHPV vaccine effectiveness [VE]), cross-protection, and type-replacement were evaluated in cohorts eligible for vaccination, by analyzing HPV prevalence of vaccine and non-vaccine types according to vaccination status.

Results

Overall, 2793 women (18-50 years) were included, 1314 of them having been in birth cohorts eligible for the HPV vaccination program (18- to 30-year-old women at enrolment). Among the latter, qHPV vaccine uptake was 59% (at least one dose), with 94% completing the schedule; standardized qHPV type prevalence was 0.6% in vaccinated versus 5.5% in unvaccinated women (P <0.001); adjusted VE against vaccine type infections was 90% (95% CI: 73%-96%) for all fully vaccinated women and 100% (95% CI not calculable) in women vaccinated before sexual debut. No statistically significant difference in overall high-risk HPV, high-risk non-vaccine HPV, or any single non-vaccine type prevalence was observed between vaccinated and unvaccinated women.

Conclusions

These results, conducted in a post-vaccine era, suggest a high qHPV VE and that a well-implemented catch-up vaccination program may be efficient in reducing vaccine-type infections in a real-world setting. No cross-protective effect or evidence of type-replacement was observed a few years after HPV vaccine introduction.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-2945-8) contains supplementary material, which is available to authorized users.

Human papillomavirus detection using the Abbott RealTime high-risk HPV tests compared with conventional nested PCR coupled to high-throughput sequencing of amplification products in cervical smear specimens from a Gabonese female population

Background

Cervical cancer is the fourth most common malignancy in women worldwide. However, screening with human papillomavirus (HPV) molecular tests holds promise for reducing cervical cancer incidence and mortality in low- and middle-income countries. The performance of the Abbott RealTime High-Risk HPV test (AbRT) was evaluated in 83 cervical smear specimens and compared with a conventional nested PCR coupled to high-throughput sequencing (HTS) to identify the amplicons.

Results

The AbRT assay detected at least one HPV genotype in 44.57% of women regardless of the grade of cervical abnormalities. Except for one case, good concordance was observed for the genotypes detected with the AbRT assay in the high-risk HPV category determined with HTS of the amplicon generated by conventional nested PCR.

Conclusions

The AbRT test is an easy and reliable molecular tool and was as sensitive as conventional nested PCR in cervical smear specimens for detection HPVs associated with high-grade lesions. Moreover, sequencing amplicons using an HTS approach effectively identified the genotype of the hrHPV identified with the AbRT test.

Cervical cancer screening in the era of HPV vaccination: A review of shifting paradigms in cytopathology

Significant changes in cervical cancer screening practice, guidelines, and prevention of cervical cancer have taken place in recent years including the raising of initial cervical cancer screening age, changes in frequency of cytology screening, and the adoption of high risk HPV and cytology co-testing for some patients; the introduction of the bivalent, quadrivalent, and 9-valent HPV vaccines; and the recent approval of high risk HPV testing as primary screening with the use of cytology as triage in positive cases. This review discusses the significance of primary HPV screening, the impact of HPV vaccination in the prevalence of cervical cancer and its precursors, the interplay between high risk HPV testing and vaccination, and the implications for clinical and cytological management. Future strategies for cervical screening in the post-vaccination era are also discussed.

Introduction of molecular HPV testing as the primary technology in cervical cancer screening: Acting on evidence to change the current paradigm

Since being introduced in the 1940s, cervical cytology - despite its limitations - has had unequivocal success in reducing cervical cancer burden in many countries. However, we now know that infection with human papillomavirus (HPV) is a necessary cause of cervical cancer and there is overwhelming evidence from large-scale clinical trials, feasibility studies and real-world experience that supports the introduction of molecular testing for HPV as the primary technology in cervical cancer screening (i.e., "HPV primary screening"). While questions remain about the most appropriate age groups for screening, screening interval and triage approach, these should not be considered barriers to implementation. Many countries are in various stages of adopting HPV primary screening, whereas others have not taken any major steps towards introduction of this approach. As a group of clinical experts and researchers in cervical cancer prevention from across Canada, we have jointly authored this comprehensive examination of the evidence to implement HPV primary screening. Our intention is to create a common understanding among policy makers, agencies, clinicians, researchers and other stakeholders about the evidence concerning HPV primary screening to catalyze the adoption of this improved approach to cervical cancer prevention. With the first cohort of vaccinated girls now turning 21, the age when routine screening typically begins, there is increased urgency to introduce HPV primary screening, whose performance may be less adversely affected compared with cervical cytology as a consequence of reduced lesion prevalence post-vaccination.

Deep sequencing of HPV E6/E7 genes reveals loss of genotypic diversity and gain of clonal dominance in high-grade intraepithelial lesions of the cervix

BACKGROUND

Human papillomavirus (HPV) is the carcinogen of almost all invasive cervical cancer and a major cause of oral and other anogenital malignancies. HPV genotyping by dideoxy (Sanger) sequencing is currently the reference method of choice for clinical diagnostics. However, for samples with multiple HPV infections, genotype identification is singular and occasionally imprecise or indeterminable due to overlapping chromatograms. Our aim was to explore and compare HPV metagenomes in abnormal cervical cytology by deep sequencing for correlation with disease states.

RESULTS

Low- and high-grade intraepithelial lesion (LSIL and HSIL) cytology samples were DNA extracted for PCR-amplification of the HPV E6/E7 genes. HPV+ samples were sequenced by dideoxy and deep methods. Deep sequencing revealed ~60% of all samples (n = 72) were multi-HPV infected. Among LSIL samples (n = 43), 27 different genotypes were found. The 3 dominant (most abundant) genotypes were: HPV-39, 11/43 (26%); -16, 9/43 (21%); and -35, 4/43 (9%). Among HSIL (n = 29), 17 HPV genotypes were identified; the 3 dominant genotypes were: HPV-16, 21/29 (72%); -35, 4/29 (14%); and -39, 3/29 (10%). Phylogenetically, type-specific E6/E7 genetic distances correlated with carcinogenic potential. Species diversity analysis between LSIL and HSIL revealed loss of HPV diversity and domination by HPV-16 in HSIL samples.

CONCLUSIONS

Deep sequencing resolves HPV genotype composition within multi-infected cervical cytology. Biodiversity analysis reveals loss of diversity and gain of dominance by carcinogenic genotypes in high-grade cytology. Metagenomic profiles may therefore serve as a biomarker of disease severity and a population surveillance tool for emerging genotypes.

Multiple high-risk HPV genotypes are grouped by type and are associated with viral load and risk factors

Investigating whether high-risk human papillomavirus (HR-HPV) types tend to become grouped in a particular way and whether factors are associated with such grouping is important for measuring the real impact of vaccination. In total, 219 women proving positive for HPV as detected by real-time PCR were included in the study. Each sample was analysed for detecting and quantifying six viral types and the hydroxymethylbilane synthase gene. Multiple correspondence analysis led to determining grouping patterns for six HR-HPV types and simultaneous association with multiple variables and whether viral load was related to the coexistence of other viral types. Two grouping profiles were identified: the first included HPV-16 and HPV-45 and the second profile was represented by HPV-31, HPV-33 and HPV-58. Variables such as origin, contraceptive method, births and pregnancies, educational level, healthcare affiliation regime, atypical squamous cells of undetermined significance and viral load were associated with these grouping profiles. Different socio-demographic characteristics were found when coinfection occurred by phylogenetically related HPV types and when coinfection was due to non-related types. Biological characteristics, the number of viral copies, temporality regarding acquiring infection and competition between viral types could influence the configuration of grouping patterns. Characteristics related to women and HPV, influence such interactions between coexisting HPV types reflecting the importance of their evaluation.

Evaluation of Type Replacement Following HPV16/18 Vaccination: Pooled Analysis of Two Randomized Trials

Background

Current HPV vaccines do not protect against all oncogenic HPV types. Following vaccination, type replacement may occur, especially if different HPV types competitively interact during natural infection. Because of their common route of transmission, it is difficult to assess type interactions in observational studies. Our aim was to evaluate type replacement in the setting of HPV vaccine randomized controlled trials (RCTs).

Methods

Data were pooled from the Costa Rica Vaccine Trial (CVT; NCT00128661) and PATRICIA trial (NCT001226810)-two large-scale, double-blind RCTs of the HPV-16/18 AS04-adjuvanted vaccine-to compare cumulative incidence of nonprotected HPV infections across trial arms after four years. Negative rate difference estimates (rate in control minus vaccine arm) were interpreted as evidence of replacement if the associated 95% confidence interval excluded zero. All statistical tests were two-sided.

Results

After applying relevant exclusion criteria, 21 596 women were included in our analysis (HPV arm = 10 750; control arm = 10 846). Incidence rates (per 1000 infection-years) were lower in the HPV arm than in the control arm for grouped nonprotected oncogenic types (rate difference = 1.6, 95% confidence interval [CI] = 0.9 to 2.3) and oncogenic/nononcogenic types (rate difference = 0.2, 95% CI = -0.3 to 0.7). Focusing on individual HPV types separately, no deleterious effect was observed. In contrast, a statistically significant protective effect (positive rate difference and 95% CI excluded zero) was observed against oncogenic HPV types 35, 52, 58, and 68/73, as well as nononcogenic types 6 and 70.

Conclusion

HPV type replacement does not occur among vaccinated individuals within four years and is unlikely to occur in vaccinated populations.

Epidemiologic Evaluation of Human Papillomavirus Type Competition and the Potential for Type Replacement Post-Vaccination

Background

Millions of women have been vaccinated with one of two first-generation human papillomavirus (HPV) vaccines. Both vaccines remain in use and target two oncogenic types (HPVs 16 and 18); however, if these types naturally compete with others that are not targeted, type replacement may occur following reductions in the circulating prevalence of targeted types. To explore the potential for type replacement, we evaluated natural HPV type competition in unvaccinated females.

Methods

Valid HPV DNA typing information was available from five epidemiological studies conducted in Canada and Brazil (n = 14,685; enrollment across studies took place between1993 and 2010), which used similar consensus-primer PCR assays, capable of detecting up to 40 HPV types. A total of 38,088 cervicovaginal specimens were available for inclusion in our analyses evaluating HPV type-type interactions involving vaccine-targeted types (6, 11, 16, and 18), and infection with each of the other HPV types.

Results

Across the studies, the average age of participants ranged from 21.0 to 43.7 years. HPV16 was the most common type (prevalence range: 1.0% to 13.8%), and in general HPV types were more likely to be detected as part of a multiple infection than as single infections. In our analyses focusing on each of the vaccine-targeted HPV types separately, many significant positive associations were observed (particularly involving HPV16); however, we did not observe any statistically significant negative associations.

Conclusions

Our findings suggest that natural HPV type competition does not exist, and that type replacement is unlikely to occur in vaccinated populations.

Bias Due to Correlation Between Times-at-Risk for Infection in Epidemiologic Studies Measuring Biological Interactions Between Sexually Transmitted Infections: A Case Study Using Human Papillomavirus Type Interactions

The clustering of human papillomavirus (HPV) infections in some individuals is often interpreted as the result of common risk factors rather than biological interactions between different types of HPV. The intraindividual correlation between times-at-risk for all HPV infections is not generally considered in the analysis of epidemiologic studies. We used a deterministic transmission model to simulate cross-sectional and prospective epidemiologic studies measuring associations between 2 HPV types. When we assumed no interactions, the model predicted that studies would estimate odds ratios and incidence rate ratios greater than 1 between HPV types even after complete adjustment for sexual behavior. We demonstrated that this residual association is due to correlation between the times-at-risk for different HPV types, where individuals become concurrently at risk for all of their partners' HPV types when they enter a partnership and are not at risk when they are single. This correlation can be controlled in prospective studies by restricting analyses to susceptible individuals with an infected sexual partner. The bias in the measured associations was largest in low-sexual-activity populations, cross-sectional studies, and studies which evaluated infection with a first HPV type as the exposure. These results suggest that current epidemiologic evidence does not preclude the existence of competitive biological interactions between HPV types.

Differential Detection of Human Papillomavirus Genotypes and Cervical Intraepithelial Neoplasia by Four Commercial Assays

Laboratories now can choose from >100 human papillomavirus (HPV) assays for cervical screening. Our previous analysis based on the data from the Danish Horizon study, however, showed that four widely used assays, Hybrid Capture 2 (HC2), cobas, CLART, and Aptima, frequently do not detect the same HPV infections. Here, we determined the characteristics of the concordant samples (all four assays returning a positive HPV test result) and discordant samples (all other HPV-positive samples) in primary cervical screening at 30 to 65 years of age (n = 2,859) and in a concurrent referral population from the same catchment area (n = 885). HPV testing followed the manufacturers' protocols. Women with abnormal cytology were managed according to the routine recommendations. Cytology-normal/HPV-positive women were invited for repeated testing in 18 months. Screening history and histologically confirmed cervical intraepithelial neoplasia (CIN) in 2.5 years after the baseline testing were determined from the national pathology register. HPV-positive women undergoing primary screening having concordant samples were more likely to harbor high-risk infections and less likely to harbor only low-risk infections than women with discordant samples. Additionally, assay signal strengths were substantially higher in concordant samples. More than 80% of ≥CIN2 results were found for women with concordant samples, and no ≥CIN2 results were found when the infection was detected by only one assay. These patterns were similar in the referral population despite the younger age and higher number of HPV infections. HPV test result discordance identified a cluster of low-risk HPV infections that were hardly ever associated with high-grade CIN and, almost exclusively, represented false-positive screening findings.

Gender-neutrality, herd effect and resilient immune response for sustainable impact of HPV vaccination

PURPOSE OF REVIEW

This review summarize the impact of various strategies of human papillomavirus (HPV) vaccination, such as vaccinating only girls or both girls and boys.

RECENT FINDINGS

Slow and inefficient implementation of HPV vaccination programmes has delayed the impact of the first human cancer vaccine. Vaccinating only girls, with a rather low coverage, has led to a limited herd effect and, thus, not full use of the HPV vaccine potential.

SUMMARY

Gender-neutral vaccination based on comparative effectiveness research will hopefully soon tackle the whole spectrum of HPV cancers in both sexes. The remaining challenges are how to ensure resilience of HPV vaccine-induced immunity and herd effect to guarantee population-level impact of HPV vaccination, and how to guard against HPV type replacement.