High Risk of New HPV Infection Acquisition Among Unvaccinated Young Men.

BACKGROUND: International data on anogenital HPV infection incidence among men are limited. METHODS: Incidence of incident-persistent (IP) anogenital HPV infections was evaluated among 295 men who have sex with men (MSM) and 1576 heterosexual men (HM) aged 16-27 years in the placebo arm of a global, multicenter 4-valent (4v) HPV vaccine trial. We estimated IP incidence (penile/scrotal, perineal/perianal, anal) for 4vHPV and 9-valent (9v) HPV vaccine types and cumulative IP incidence over 36 months. RESULTS: IP infection incidence per 100 person-years (95% CI) among HM for 4vHPV and 9vHPV types was 4.1 (3.5-4.9) and 6.8 (5.9-7.6) at penile/scrotal, and 1.2 (.8-1.6) and 1.9 (1.5-2.4) at perineal/perianal sites, respectively; and among MSM, IP infection incidence was 2.3 (1.3-3.8) and 3.2 (2.0-4.9) at penile/scrotal, 6.8 (4.9-9.2) and 9.0 (6.9-11.6) at perineal/perianal, and 12.0 (9.4-15.1) and 16.8 (13.7-20.2) at anal sites, respectively. Cumulative IP incidence over 36 months (excluding anal canal; any 9vHPV type) was higher among MSM versus HM (24.1% vs 18.4%). CONCLUSIONS: A substantial proportion of unvaccinated men of catch-up vaccination age developed IP 9vHPV-related infections. Gender-neutral vaccination could decrease male HPV infection, contribute to herd protection, and reduce disease burden. Clinical Trials Registration. NCT00090285.

Impact of a carrageenan gel on viral load of genital human papillomavirus infections in sexually active women: Findings from the Carrageenan-gel Against Transmission of Cervical Human papillomavirus (CATCH) trial.

Previous research has shown that women's use of a carrageenan gel reduces the risk of acquiring genital human papillomavirus (HPV) infections but does not help to clear existing ones. Although gel use may not result in complete clearance, it may decrease the viral load of HPV infections. We tested this hypothesis in the Carrageenan-gel Against Transmission of Cervical Human papillomavirus (CATCH) randomized controlled trial. Participants of the CATCH study were selected for viral load testing if they had completed the first four study visits and tested positive for HPV42 or HPV51 in at least one of these visits. HPV42 and HPV51 were chosen as they were among the most abundant low- and high-risk types, respectively, in the study sample. We measured viral load with a type-specific real-time polymerase chain reaction. Results were displayed using summary statistics. Of 461 enrolled participants, 39 were included in the HPV42 analysis set and 56 in the HPV51 analysis set. The median time between visits 1 and 4 was 3.7 months. The viral load (copies/cell) of HPV42 ranged from <0.001 to 13 434.1, and that of HPV51 from <0.001 to 967.1. The net median change in HPV42 viral load over all four visits was -1.04 copies/cell in the carrageenan and -147 copies/cell in the placebo arm (Wilcoxon rank sum test, p = 0.26). There was no net median change in HPV51 viral load over all four visits in either arm (p = 0.45). The use of a carrageenan-based gel is unlikely to reduce the viral load of HPVs 42 or 51.

Use of a carrageenan-based gel had no impact on anal HPVs 16 and 18 viral loads in gay, bisexual, and other men who have sex with men.

The Lubricant Investigation in Men to Inhibit Transmission of human papillomavirus (HPV) Infection randomized control trial in gay, bisexual, and other men who have sex with men (gbMSM) found that carrageenan use neither reduced acquisition of anal HPV infections nor influenced infection clearance. To investigate carrageenan's lack of protective effect, we compared the change in anal HPV16 and HPV18 viral loads following carrageenan use against placebo. We restricted our analysis to participants who completed the first four study visits and had a valid baseline sample (n = 161, 54 HIV-positive). Samples were tested for HPV detection using the linear array PCR assay. HPV16- and/or HPV18-positive samples were tested for viral load using real-time PCR. For participants who tested HPV16- (n = 29) or HPV18-positive (n = 10) at least once across visits 1-4, we compared the change in type-specific viral load between study arms using the Mann-Whitney U test. Although the median net change in HPV16 and HPV18 viral loads across visits 1-4 was higher in the treatment than placebo arm (HPV16: 0.68 vs. 0.18 copies/cell, p = 0.60; HPV18: 18.32 vs. 10.12 copies/cell, p = 0.52), these differences were not statistically significant. Results were similar by HIV status. Carrageenan use did not impact anal HPV16 or HPV18 viral loads, which may further explain its lack of protective effect in gbMSM.

Incidence of cervical precancerous lesions and cervical cancer in Denmark from 2000 to 2019: Population impact of multi-cohort vaccination against human papillomavirus infection.

In Denmark, vaccination against human papillomavirus (HPV) has been implemented in the children's vaccination program (January 2009) and in multiple catch-up cohorts (October 2008 in girls 13-15 years and in August 2012 in women up to 27 years). In the present study we estimate incidence of cervical intraepithelial neoplasia grade 3 (CIN3), adenocarcinoma in situ (AIS), squamous cell carcinoma (SCC) and adenocarcinoma (AC) during 2000-2019. All cases of CIN3 and AIS were identified from the nationwide Pathology Data Bank, while SCC and AC were identified from the Danish Cancer Registry. We calculated age-standardized incidence rates and estimated annual percentage change (EAPC) with corresponding 95% confidence interval (CI) for the periods before vaccination implementation (2000-2005), early after implementation of childhood HPV vaccination and the first catch-up vaccination program (2006-2012), and after implementation of the second catch-up program (2013-2019). For CIN3 and AIS, age-specific incidence rates and EAPCs were calculated. An increasing age-standardized incidence was observed before introduction of HPV vaccination (2000-2005) for CIN3 [EAPCCIN3 : 3.0 (95% CI 1.7 to 4.3)] and AIS [EAPCAIS : 3.5 (95% CI 0.7 to 6.4)]. In the most recent period (2013-2019), following implementation of the second catch-up program, a decrease was observed for both CIN3 [EAPCCIN3 : -6.5 (95% CI -8.3 to -4.8)], AIS [EAPCAIS : -8.7 (95% CI -12.3 to -5.1)] and for SCC [EAPCSCC : -3.9 (95% CI -7.5 to -0.2)]. In this study we document a decrease in the incidence of CIN3, AIS and SCC in the period after implementation of multi-cohort HPV vaccination in Denmark.

Anogenital Human Papillomavirus (HPV) Infection, Seroprevalence, and Risk Factors for HPV Seropositivity Among Sexually Active Men Enrolled in a Global HPV Vaccine Trial.

BACKGROUND: In men, the incidence of human papillomavirus (HPV)-related cancer is rising, but data regarding male HPV infection and seroprevalence are available from only a few countries. METHODS: This analysis of a global HPV vaccine trial evaluated baseline data from 1399 human immunodeficiency virus-negative heterosexual men (HM) and men who have sex with men (MSM). Key objectives included assessment of HPV prevalence and risk factors for seropositivity to 9-valent HPV (9vHPV) vaccine types (6, 11, 16, 18, 31, 33, 45, 52, and 58), and concordance between seropositivity and prevalent HPV type. RESULTS: Overall, 455 of 3463 HM (13.1%) and 228 of 602 MSM (37.9%) were HPV DNA positive for any 9vHPV vaccine type at baseline. Infection prevalence and seroprevalence (≥1 9vHPV vaccine type) were 13.2% and 8.1%, respectively, among 333 HM from Europe, and 37.9% and 29.9%, respectively, among 335 MSM from Europe or North America. Among men with baseline infection, MSM had higher seroprevalence for concordant HPV types (39.5% vs 10.8% in HM). The seropositivity risk (irrespective of baseline infection status) was higher among MSM versus HM (age-adjusted odds ratio, 3.0 [95% confidence interval, 2.4-6.4]). Among MSM, statistically significant seropositivity risk factors included younger age at sexual debut, higher number of receptive anal sex partners, and less frequent condom use. No factors assessed were associated with seropositivity in HM. CONCLUSIONS: Higher proportions of MSM than HM were HPV DNA positive and seropositive, and concordance between HPV DNA positivity and seropositivity, a potential marker of true infection versus carriage, was higher in MSM. Most MSM and HM were seronegative for all 9vHPV vaccine types, suggesting the potential benefit of catch-up vaccination after sexual debut.Clinical Trials Registration. NCT00090285.

Efficacy of a carrageenan gel in preventing anal human papillomavirus (HPV) infection: interim analysis of the Lubricant Investigation in Men to Inhibit Transmission of HPV Infection (LIMIT-HPV) randomised controlled trial.

BACKGROUND: Carrageenan, a non-toxic gelling agent derived from red algae, has potent anti-human papillomavirus (HPV) activity in in vitro and animal studies. We assessed, in an interim analysis, the efficacy of a carrageenan-based gel in reducing the risk of new detections of anal HPV among gay, bisexual and other men who have sex with men (gbMSM). METHODS: The LIMIT-HPV study (Lubricant Investigation in Men to Inhibit Transmission of HPV Infection) is a phase IIb, double-blind, placebo-controlled randomised controlled trial conducted in Montreal, Canada. gbMSM were randomly assigned (1:1) to receive a carrageenan-based or placebo gel. Participants were instructed to apply the gel to the anus, condom and/or partners' penis before and-as required-during receptive anal intercourse. Questionnaire data and anal samples were collected at 0, 1, 2, 3, 6, 9 and 12 months. We estimated new detections of anal HPV infection(s) detected via Linear Array using Cox proportional hazards models. RESULTS: Participants recruited from February 2016 to December 2019 were randomly assigned to the carrageenan (n=127) or placebo (n=128) arm. The efficacy and safety analyses included 201 and 210 participants. The median follow-up time was 7.6 months (range: 0-28.5) in the carrageenan group and 9.3 months (range: 0-40.7) in the placebo group. The HR for new detections was 1.21 (95% CI 0.86 to 1.70): 69.4% and 65.1% new detections of HPV in the carrageenan and placebo arms, respectively. More adverse events were reported in the carrageenan (59.8%) compared with the placebo (39.8%) arm. CONCLUSIONS: The interim analysis did not demonstrate a protective effect of carrageenan on the risk of new detections of anal HPV infection among gbMSM. Carrageenan gel use was associated with a higher proportion of adverse events. Given these findings and the (assumed) low probability that a beneficial effect would be found by the study's end, the trial was terminated as recommended by the Data Safety and Monitoring Board. TRIAL REGISTRATION NUMBER: NCT02354144.

Efficacy of AS04-Adjuvanted Vaccine Against Human Papillomavirus (HPV) Types 16 and 18 in Clearing Incident HPV Infections: Pooled Analysis of Data From the Costa Rica Vaccine Trial and the PATRICIA Study.

Clinical trial data and real-world evidence suggest that the AS04-adjuvanted vaccine targeting human papillomavirus types 16 and 18 (AS04-HPV-16/18) vaccine provides nearly 90% protection against cervical intraepithelial neoplasia grade 3 or higher irrespective of type, among women vaccinated before sexual debut. This high efficacy is not fully explained by cross-protection. Although AS04-HPV-16/18 vaccination does not affect clearance of prevalent infections, it may accelerate clearance of newly acquired infections. We pooled data from 2 large-scale randomized controlled trials to evaluate efficacy of the AS04-HPV-16/18 vaccine against clearance of nontargeted incident infections. Results of our analysis do not suggest an effect in expediting clearance of incident infections.

Defining benchmarks for tolerable risk thresholds in cancer screening: Impact of HPV vaccination on the future of cervical cancer screening.

The performance of cervical cancer screening will decline as a function of lower disease prevalence-a consequence of successful human papillomavirus (HPV) vaccination. Replacement of cytology with molecular HPV testing as the primary screening test and adoption of risk-based screening, with less intense screening of vaccinated individuals and initiated at older ages is expected to improve efficiency. However, policy officials may decide to further reduce or eliminate screening as the ratio of benefits to harms continues to decline. To evaluate the level of risk currently tolerated for different cancers in the United States (ie, for which clinical guidelines do not recommend secondary prevention though effective screening methods exist), we used US cancer registry data to compare incidence (2008-2012) and survival (1988-2011) associated with different cancers for which organized screening is recommended and not recommended. The most common cancer at ages 70 to 74 years (ie, age group with highest cancer incidence and reasonable life expectancy to consider screening in the US) satisfying Wilson and Jungner's classic screening criteria was vulvar cancer (incidence = 9/100 000 females). In comparison, the incidence of cervical cancer among females 65 years of age (the upper recommended age limit for screening) was 13 cases per 100 000 females (low as a reflection of effective screening), whereas 10-year survival was 66% (similar to vulvar cancer at 67%). Our approach of defining tolerable risk in cancer screening could help guide future decisions to modify cervical screening programs.

Development and validation of an individualized risk prediction model for oropharynx cancer in the US population.

BACKGROUND: The incidence of oropharynx cancers has increased substantially in the United States. However, risk stratification tools for the identification of high-risk individuals do not exist. In this study, an individualized risk prediction model was developed and validated for oropharynx cancers in the US population. METHODS: A synthetic, US population-based case-control study was conducted. Oropharynx cancer cases diagnosed at Ohio State University (n = 241) were propensity-weighted to represent oropharynx cancers occurring annually in the United States during 2009-2014 (n = 12,656). Controls (n = 9327) included participants in the National Health and Nutrition Examination Survey (2009-2014) and represented the annual US population aged 30 to 69 years (n = 154,532,508). The individualized 1-year absolute risk of oropharynx cancer was estimated with weighted logistic regression. RESULTS: The risk prediction model included age, sex, race, smoking, alcohol use, lifetime sexual partners, and oral oncogenic human papillomavirus (HPV) status. The model had good discrimination and calibration in split-sample validation (area under the curve [AUC], 0.94; 95% confidence interval [CI], 0.92-0.97; observed/expected [O/E], 1.01; 95% CI, 0.70-1.32) and external validation (AUC, 0.87; 95% CI, 0.84-0.90; O/E, 1.08; 95% CI, 0.77-1.39). In the US population, 1-year predicted risks of oropharynx cancer were highest for older individuals (21.1/100,000 for 65- to 69-year-olds), men (13.9/100,000), whites (10.4/100,000), smokers (18.0/100,000 for >20 pack-years), heavy alcohol users (18.4/100,000), and those with prevalent oral oncogenic HPV (140.4/100,000). The risk prediction model provided substantial risk stratification, with approximately 77% of all oropharynx cancers and approximately 99% of HPV-positive oropharynx cancers occurring in the 10% of the US population with the highest model-predicted risk. CONCLUSIONS: This risk prediction model will enable the efficient design of studies to address the outstanding questions pertaining to the natural history, screening, and secondary prevention of oropharynx cancers.

Risk of oral tongue cancer among immunocompromised transplant recipients and human immunodeficiency virus-infected individuals in the United States.

BACKGROUND: Oral tongue cancer incidence has increased among whites in the United States; however, the cause remains unknown. If an infectious agent is implicated, then elevated risk would be expected among immunosuppressed individuals. METHODS: By using population-based registry linkage information from the US Transplant Cancer Match and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) Cancer Match studies, the authors examined the risk of oral tongue squamous cell carcinoma (SCC) among immunocompromised transplantation recipients and HIV-infected individuals. In addition, the risks of oropharyngeal SCC (strongly related to human papillomavirus infection; modestly affected by immunosuppression), other tobacco/alcohol-related oral cavity SCCs (not thought to be infection/immunosuppression-related), and non-Hodgkin lymphoma of oral cavity/pharynx (strongly related to Epstein-Barr virus; profoundly affected by immunosuppression) were evaluated. RESULTS: Compared with the general population, the risk of non-Hodgkin lymphoma was strongly increased (standardized incidence ratio [SIR] > 8.0). The risk of all SCCs was modestly and similarly elevated among transplantation recipients (SIR range, 2.2-2.7; Pheterogeneity = .2); whereas, among HIV-infected individuals, the risk of oral tongue SCC was higher compared with the risk of other SCCs (SIR, 3.0 vs 1.7 [for oropharyngeal SCCs] and 2.3 [for other oral cavity SCCs]; Pheterogeneity < .001). The risk of SCCs was significantly higher among men, older individuals, and whites; and risk increased with the time since transplantation/AIDS onset. The risk of oral tongue SCC was significantly higher among HIV-infected men who have sex with men compared with the average risk in HIV-infected individuals (adjusted incidence rate ratio = 2.0). CONCLUSIONS: Similar modest increases in the risk of oral tongue and other oral cavity SCCs do not suggest that an infectious agent or exposure profoundly affected by immunosuppression underlies the increase in oral tongue cancer. Cancer 2018;124:2515-22. © 2018 American Cancer Society.

Trends in cervical cancer incidence in younger US women from 2000 to 2013.

OBJECTIVE: This study aimed to assess the temporal trends in invasive cervical cancer (ICC) incidence rates among 21-25year-olds. US guidelines no longer recommend screening prior to age 21, and concerns have been raised that delayed screening initiation may increase ICC incidence among young women. METHODS: This study utilized ICC incidence data from 18 US population-based cancer registries in SEER from 2000 to 2013 and Pap test prevalence data from the Behavioral Risk Factor Surveillance System from 1996 to 2012. Trends were evaluated with annual percent changes (APCs) using Joinpoint regression. RESULTS: The prevalence of never having a Pap test before age 21 increased from 22.0% in 1996-2004 to 38.3% in 2006-2012 (APC=+5.48, 95%CI=+4.20, +7.50). Despite this decline in screening, ICC incidence among 21-23year olds significantly declined between 2000 and 13 (APC=-5.36, 95%CI=-7.83,-2.82), particularly from 2006 to 2013 (APC=-9.70, 95%CI=-15.79, -3.17). ICC incidence remained constant among 24-25year olds (APC=+0.45, 95%CI=-2.00, 2.97). Compared to women born in 1978-1985, women born in 1986-1991 had a higher prevalence of never receiving a Pap test prior to 21 (35.4% vs. 22.1%, p<0.001), but a lower ICC incidence at 21-23 (0.98 vs. 1.55 per 100,000, p<0.001). CONCLUSION: While US females born in 1986-1991 were less likely to receive a Pap test before age 21, diagnoses of ICC in the early 20s were rare and lower than for those born in earlier years. This provides reassurance that the updated guidelines to delay screening until 21 has not resulted in a population-level increase in ICC rates among young women.

Approaches for triaging women who test positive for human papillomavirus in cervical cancer screening.

Substantial evidence exists to support the introduction of molecular testing for human papillomavirus (HPV) as the primary technology in cervical cancer screening. While HPV testing is much more sensitive than cytology for detection of high-grade precancerous lesions, it is less specific. To improve efficiency, it is therefore recommended that a specific test (like cytology) be used in triaging HPV positive women to colposcopy. A number of studies have been conducted that support the use of cytology alone or in conjunction with HPV genotyping for triage. The decision to incorporate genotyping also depends on the commercial HPV test that is selected since not all tests provide results for certain individual high-risk types. Regardless of whether policy officials decide to adopt a triage approach that incorporates genotyping, the use of liquid based cytology (LBC) may also improve screening performance by reducing diagnostic delays. With LBC, the same cell suspension from a single collection may be used for HPV testing and a smear can be immediately prepared if HPV status is positive. This was a critical lesson from a community based demonstration project in Montreal (VASCAR study), where conventional cytology exists and specimen co-collection was not permitted for ethical reasons, requiring HPV positive women to return for an additional screening visit prior to colposcopy.

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.

Cervical Infection With Vaccine-Associated Human Papillomavirus (HPV) Genotypes as a Predictor of Acquisition and Clearance of Other HPV Infections.

BACKGROUND: Recent birth cohorts vaccinated against human papillomavirus (HPV) may be protected against up to 4 genotypes (HPV-6, -11, -16, and -18). If natural competition exists between these and other HPV types, then the prevalence of other types may increase after vaccination. METHODS: Cohort information from 3 studies was used to compare acquisition and clearance of 30 different HPV types (individually and grouped by species), according to infection status with vaccine-targeted types at baseline and the time of the index infection, respectively. Hazard ratios (HRs) were adjusted for predictors of multiple-type infection. RESULTS: Among 3200 females across all studies, 857 were infected with HPV at baseline, and 994 acquired new infections during follow-up. Females infected with HPV-16 were at higher risk of acquiring other α-9 HPV types (HR, 1.9; 95% confidence interval [CI], 1.2-3.0) but at similar risk of clearing existing α-9 HPV infections (HR, 0.9; 95% CI, .7-1.3). Females infected with vaccine-targeted types were generally at higher risk of acquiring additional types (HRs, > 1.0) and at equal risk of clearing existing infections. Accounting for multiple comparisons, none of the HRs of < 1.0 or >1.0 were statistically significant in our analyses of acquisition or clearance. CONCLUSIONS: Vaccine-targeted HPV types do not appear to compete with other types, suggesting that HPV type replacement is unlikely to occur.

Younger age distribution of cervical cancer incidence among survivors of pediatric and young adult cancers.

BACKGROUND: Pediatric and young adult (PAYA) cancer survivors may have an earlier onset of chronic diseases compared with the general population. We compared the age at cervical cancer diagnosis between PAYA cancer survivors and females in the general US population. METHODS: We used longitudinal data from 9 population-based registries of the Surveillance, Epidemiology, and End Results program collected between 1973 and 2010. PAYA cancer survivors were females diagnosed with any cancer before age 30 years, survived at least 5 years post-diagnosis, and were subsequently diagnosed with invasive cervical cancer (n=46). The general US population comprised females who were diagnosed with invasive cervical cancer as the primary malignancy (n=26,956). We estimated the difference in median age at diagnosis (ß50) and bootstrap 95% confidence limits (CL) of invasive cervical cancer after adjustment for year of diagnosis and race. RESULTS: The median age at diagnosis of invasive cervical cancer was 33 years for female PAYA cancer survivors and 40 years for females in the general US population (ß50=-7.0, 95% CL: -11, -3.2). Similar differences were observed across subgroups of stage and histologic subtype of invasive cervical cancer. CONCLUSION: Our results suggest that PAYA cancer survivors are diagnosed with invasive cervical cancer at a substantially younger age compared with females without a prior cancer diagnosis in the general US population. This issue warrants further study, and could have implications for determining age at initiation or frequency of cervical cancer screening if younger age at diagnosis is attributable to an underlying biological phenomenon.

Lung cancer screening: review and performance comparison under different risk scenarios.

Lung cancer is currently one of the most common malignant diseases and is responsible for substantial mortality worldwide. Compared with never smokers, former smokers remain at relatively high risk for lung cancer, accounting for approximately half of all newly diagnosed cases in the US. Screening offers former smokers the best opportunity to reduce their risk of advanced stage lung cancer and there is now evidence that annual screening using low-dose computed tomography (LDCT) is effective in preventing mortality. Studies are being conducted to evaluate whether the benefits of LDCT screening outweigh its costs and potential harms and to determine the most appropriate workup for patients with screen-detected lung nodules. Program efficiency would be optimized by targeting high-risk current smokers, but low uptake among this group is a concern. Former smokers may be invited for screening; however, if fewer long-term current smokers and more former smokers with long quit duration elect to attend, this could have very adverse effects on cost and screening test parameters. To illustrate this point, we present three possible screening scenarios with lung cancer prevalence ranging from between 0.62 and 5.0 %. In summary, cost-effectiveness of lung cancer screening may be improved if linked to successful smoking cessation programs and if better approaches are developed to reach very high-risk patients, e.g., long-term current smokers or others based on more accurate risk prediction models.

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

Currently, 2 vaccines exist that prevent infection by the genotypes of human papillomavirus (HPV) responsible for approximately 70% of cervical cancer cases worldwide. Although vaccination is expected to reduce the prevalence of these HPV types, there is concern about the effect this could have on the distribution of other oncogenic types. According to basic ecological principles, if competition exists between ≥2 different HPV types for niche occupation during natural infection, elimination of 1 type may lead to an increase in other type(s). Here, we discuss this issue of "type replacement" and present different epidemiologic approaches for evaluation of HPV type competition. Briefly, these approaches involve: 1) calculation of the expected frequency of coinfection under independence between HPV types for comparison with observed frequency; 2) construction of hierarchical logistic regression models for each vaccine-targeted type; and 3) construction of Kaplan-Meier curves and Cox models to evaluate sequential acquisition and clearance of HPV types according to baseline HPV status. We also discuss a related issue concerning diagnostic artifacts arising when multiple HPV types are present in specific samples (due to the inability of broad-spectrum assays to detect certain types present in lower concentrations). This may result in an apparent increase in previously undetected types postvaccination.

Cervical human papillomavirus detection is not affected by menstrual phase.

OBJECTIVES: In many settings, human papillomavirus (HPV) DNA testing already plays an important role in cervical cancer screening. It is unclear whether hormonal fluctuations associated with menstrual phase or oral contraceptive (OC) use have any effect on HPV detection. We evaluated the effects of OC use and timing of cervical sampling in relation to women's last menstrual period (LMP) on HPV detection, and viral load in the Brazilian Ludwig-McGill cohort study. METHODS: Women in the cohort were followed every 4-6 months, and at each clinic visit they were asked to complete a questionnaire and to provide a cervical sample for HPV testing. Specimens from 6093 patient visits (n=2209 women) were categorised according to date of LMP into four distinct phases: follicular (days 5-9), midcycle (days 10-15), luteal (days 16-22), or late luteal (days 23-31). RESULTS: Compared with follicular phase (referent group), HPV detection did not differ according to reported LMP for midcycle (OR=1.14, 95% CI 0.95 to 1.37), luteal (OR=1.03, 95% CI 0.85 to 1.25), or late luteal menstrual phase (OR=1.01, 95% CI 0.83 to 1.24), and was also not influenced by OC use. Analyses restricted to high-risk HPV types (grouped) and HPVs 16 and 18 (separately), produced similar non-significant associations. For HPV-positive samples, we found that the menstrual phase did not influence the total viral load. CONCLUSIONS: These results indicate HPV detection is not associated with menstrual phase. Our findings suggest that standardising the timing of specimen collection for HPV testing is not necessary.

Efficacy and safety of a self-applied carrageenan-based gel to prevent human papillomavirus infection in sexually active young women (CATCH study): an exploratory phase IIB randomised, placebo-controlled trial.

Background: Carrageenan demonstrated potent anti-HPV (human papillomavirus) activity in vitro and in animal models. The Carrageenan-gel Against Transmission of Cervical Human papillomavirus trial's interim analysis (n = 277) demonstrated a 36% protective effect of carrageenan against incident HPV infections. Herein, we report the trial's final results. Methods: In this exploratory phase IIB randomised, placebo-controlled trial, we recruited healthy women aged ≥18 years primarily from health service clinics at two Canadian Universities in Montreal. Participants were randomised (1:1) by the study coordinator (using computer-assisted block randomisation with randomly variable block sizes up to a block size of eight) to a carrageenan-based or placebo gel to be self-applied every other day for the first month and before/after intercourse. Participants, study nurses, and laboratory technicians (HPV testing and genotyping) were blinded to group assignment. At each visit (months 0, 0.5, 1, 3, 6, 9, 12), participants provided questionnaire data and a self-collected vaginal sample (tested for 36 HPV types, Linear Array). The primary outcome was type-specific HPV incidence (occurring at any follow-up visit). Intention-to-treat analyses for incidence were conducted using Cox proportional hazards regression models, including participants with ≥2 visits. Safety analyses included all participants randomised. This trial is registered with the ISRCTN registry, ISRCTN96104919. Findings: Between Jan 16, 2013 and Sept 30, 2020, 461 participants (enrolled) were randomly assigned to the carrageenan (n = 227) or placebo (n = 234) groups. Incidence and safety analyses included 429 and 461 participants, respectively. We found 51.9% (108/208) of participants in carrageenan and 66.5% (147/221) in placebo arm acquired ≥1 HPV type (hazard ratio 0.63 [95% CI: 0.49-0.81], p = 0.0003). Adverse events were reported by 34.8% (79/227) and 39.7% (93/234) of participants in carrageenan and placebo arm (p = 0.27), respectively. Interpretation: Consistent with the interim analysis, use of a carrageenan-based gel compared to placebo resulted in a 37% reduction in risk of incident genital HPV infections in women with no increase in adverse events. A carrageenan-based gel may complement HPV vaccination. Funding: Canadian Institutes of Health Research, CarraShield Labs Inc.