Human papillomavirus (HPV) type distribution and serological response to HPV type 6 virus-like particles in patients with genital warts

Assessing incidence and economic burden of genital warts with data from a US commercially insured population

OBJECTIVE

This study examined the incidence of and healthcare costs attributable to genital warts within a large US commercially insured, geographically dispersed population.

RESEARCH DESIGN AND METHODS

Using a retrospective cohort study design, this longitudinal analysis assessed administrative claims of integrated medical and pharmacy encounters from five Blue Cross Blue Shield health plans. Genital warts cases were identified using a methodology previously described by Insinga et al.

MAIN OUTCOME MEASURES

Age- and gender-specific incidence of genital warts per 1000 person-years in 2004, and duration-of-episode attributable direct medical costs (2004 US dollars) and healthcare resource utilization of cases diagnosed in 2002. Overall outcome measures were age- and gender-adjusted to the 2004 US civilian population.

RESULTS

Genital warts incidence in 2004 was 1.2/1000 females and 1.1/1000 males. Incidence was highest among females aged 20-24 (4.6/1000) and males aged 25-29 (2.7/1000). Projected overall incidence was over 340,000 cases in 2004. Mean duration-of-episode per incident case in 2002 was 95.4 days (males 116.3 days; females 69.7 days). Mean ambulatory visits per episode were 1.5 for females and 1.9 for males, with <1 drug prescription/episode. Mean costs were $647/episode ($745 males; $528 females). The 2004 estimated economic burden was $760 per 1000 individuals in the general population with the total exceeding $220 million.

LIMITATIONS

Only those genital warts cases that sought evaluation or for which the treating provider was covered by the health plan were captured in the study.

CONCLUSIONS

Genital warts represent a significant health and cost burden in the US. Adoption of novel healthcare technologies such as vaccines along with traditional interventions such as physician education of signs and symptoms, condom use and abstinence or limiting number of sexual partners may significantly help reduce the burden of genital warts.

[Human papillomavirus and cervical neoplasia]

Human papillomavirus (HPV) has been established as an important etiological factor for the development of cervical cancer. This DNA virus primarily infects the epithelium and can induce benign and malignant lesions of the mucous membranes and skin. Some HPVs are considered high risk due to their role in malignant progression of cervical tumors. Genital HPV infections are common and usually transient among young sexually active women. Only a small fraction of infected women develop cervical cancer, implying the involvement of environmental and genetic cofactors in cervical carcinogenesis. Classification, virology, pathology, natural history, epidemiological features of genital HPV infection, and future prospects for cervical cancer prevention with HPV vaccines will be reviewed here.

Oncogenic activities of human papillomaviruses

Infectious etiologies for certain human cancers have long been suggested by epidemiological studies and studies with experimental animals. Important support for this concept came from the discovery by Harald zur Hausen's group that human cervical carcinoma almost universally contains certain "high-risk" human papillomavirus (HPV) types. Over the years, much has been learned about the carcinogenic activities of high-risk HPVs. These studies have revealed that two viral proteins, E6 and E7, that are consistently expressed in HPV-associated carcinomas, are necessary for induction and maintenance of the transformed phenotype. Hence, HPV-associated tumors are unique amongst human solid tumors in that they are universally caused by exposure to the same, molecularly defined oncogenic agents, and the molecular signal transduction pathways subverted by these viral transforming agents are frequently disrupted in other, non-virus-associated human cancers.

Epidemiologic natural history and clinical management of Human Papillomavirus (HPV) Disease: a critical and systematic review of the literature in the development of an HPV dynamic transmission model

BACKGROUND

Natural history models of human papillomavirus (HPV) infection and disease have been used in a number of policy evaluations of technologies to prevent and screen for HPV disease (e.g., cervical cancer, anogenital warts), sometimes with wide variation in values for epidemiologic and clinical inputs. The objectives of this study are to: (1) Provide an updated critical and systematic review of the evidence base to support epidemiologic and clinical modeling of key HPV disease-related parameters in the context of an HPV multi-type disease transmission model which we have applied within a U.S. population context; (2) Identify areas where additional studies are particularly needed.

METHODS

Consistent with our and other prior HPV natural history models, the literature review was confined to cervical disease and genital warts. Between October 2005 and January 2006, data were gathered from the published English language medical literature through a search of the PubMed database and references were examined from prior HPV natural history models and review papers. Study design and data quality from individual studies were compared and analyses meeting pre-defined criteria were selected.

RESULTS

Published data meeting review eligibility criteria were most plentiful for natural history parameters relating to the progression and regression of cervical intraepithelial neoplasia (CIN) without HPV typing, and data concerning the natural history of HPV disease due to specific HPV types were often lacking. Epidemiologic evidence to support age-dependency in the risk of progression and regression of HPV disease was found to be weak, and an alternative hypothesis concerning the time-dependence of transition rates is explored. No data were found on the duration of immunity following HPV infection. In the area of clinical management, data were observed to be lacking on the proportion of clinically manifest anogenital warts that are treated and the proportion of cervical cancer cases that become symptomatic by stage.

CONCLUSION

Knowledge of the natural history of HPV disease has been considerably enhanced over the past two decades, through the publication of an increasing number of relevant studies. However, considerable opportunity remains for advancing our understanding of HPV natural history and the quality of associated models, particularly with respect to examining HPV age- and type-specific outcomes, and acquired immunity following infection.

The role of NH4Cl and cysteine proteases in Human Papillomavirus type 16 infection

BACKGROUND

The infectious pathway of the non-enveloped Human Papillomavirus Type 16 (HPV16) includes binding to the cell surface, clathrin-mediated endocytosis, and penetration into an endosome. HPV16 infection was shown to decrease in the presence of the lysosomotrophic neutralizing agent ammonium chloride (NH4Cl). NH4Cl neutralizes acidic endo-lysosome compartments, thus suggesting that pH was responsible for PV capsid conformational changes leading endosome escape.

RESULTS

However, our data suggested that NH4Cl blocked infection by preventing the movement of PV viral particles from the early endosome to the caveosome as was shown for JC virus 12. We have confirmed that HPV 16 infection requires the trafficking of reporter-virions to the caveosome as is the case for BPV1 34. In this manuscript we propose that the observed decrease in infection of PV in the presence of NH4Cl was due to a loss of movement of reporter-virions to caveosomes. We also demonstrate that cysteine proteases are involved in the infectious process, and that cathepsin B treatment of viral particles was shown to overcome the block of infection observed in the presence of furin inhibition. We confirmed the need for cathepsin B in HPV16 infection using cathepsin B null mouse embryonic fibroblasts.

CONCLUSION

We present data that suggest HPV16 infection is in part mediated by cysteine proteases, and that NH4Cl blocks the intracellular trafficking of infectious viral particles. To our knowledge this is the first demonstration that cysteine proteases influence the infection of a non-enveloped virus.

Management strategies and cost effectiveness in the prevention of cervical cancer

This paper introduces the burden of cervical cancer and the primary and secondary preventative interventions currently available, and provides an overview of the bivalent and quadrivalent human papillomavirus (HPV) vaccines. A brief account of the virology and the clinical efficacy of both is given. Examinations of the two main types of cost analyses, cost-effective and cost-benefit, as well as examples, are presented in addition to the possible impact these analyses and further economic models will have on budget and policy making decisions. In general, most cost analyses provide support for the implementation of primary prevention strategies, HPV immunization, in conjunction with cervical cancer screening programs. Vaccination against HPV, therefore, is a cost-effective cervical cancer prevention mechanism.

Human papillomavirus--lessons from history and challenges for the future

Human papillomavirus (HPV) is the most common sexually transmitted infection, and HPV-associated cervical cancer is a significant cause of morbidity and mortality worldwide. Recent advances in molecular biology have facilitated testing for HPV infection. Over the last decade, national and international cervical cancer screening programs have added HPV testing to their guidelines. The use of HPV prophylactic and therapeutic immunization may expand the need for systematic HPV testing to help define eligible subgroups for intervention. Given the worldwide variation in HPV subtype prevalence, basic Pap testing will continue to play an important role in cervical cancer screening, and methods to improve Pap smear sensitivity may help to improve screening in the future. This review focuses on the genetics and cellular biology of HPV infection, the natural history and prevalence of HPV infections, cervical cancer screening around the world and in Canada in particular, and evolving research to improve screening methods.

Human papillomavirus vaccine acceptability among young adult men

BACKGROUND

For human papillomavirus (HPV) vaccination to have maximum benefit to public health, both men and women should be vaccinated. Although efficacy trials in men are still ongoing, the HPV vaccine will likely be licensed for men in the near future. Little is known about men's interest in HPV vaccination. This study assessed whether informing men about the benefits of male HPV vaccination for their female sexual partner(s) boosted interest in the HPV vaccine beyond informing them about the benefits to men alone. Predictors of HPV vaccine acceptability were also identified.

METHODS

Heterosexual male college students (n = 356) were randomly assigned to receive a self-protection versus a self-protection and partner protection message about HPV and the quadrivalent HPV vaccine. Participants provided demographic and sexual history information, HPV-related awareness and knowledge, health beliefs, and HPV vaccination intentions.

RESULTS

: Men reported moderate interest in the HPV vaccine; vaccine acceptability did not differ by experimental condition. A multivariate regression model identified several independent predictors of HPV vaccine acceptability including sexual activity, perceived susceptibility to HPV, perceived benefits of the vaccine, perceived hassle and cost of vaccination, self-efficacy for vaccination, and perceived norms for vaccination.

CONCLUSION

Informing men about the benefits of male HPV vaccination for reducing cervical cancer risk in women did not increase men's interest in the vaccine. Correlates of vaccine acceptability among men were generally consistent with those identified for women. Findings have important implications for future HPV vaccination campaigns targeting young adult men.

Effects of information framing on human papillomavirus vaccination

BACKGROUND

In June 2006, the first vaccine to prevent human papillomavirus (HPV) transmission was approved for use in females in the United States. Because the vaccine was approved for females as young as 9, its success depends on parents' and individuals' willingness to accept vaccination. Little is known about how attitudes toward this vaccine will be influenced by the way the vaccine is portrayed in the media or in public debate.

METHODS

To assess the effects of information framing on intentions to vaccinate self or female children, if appropriate, 635 adults read one of three short descriptive paragraphs about the vaccine, each of which emphasized a different aspect of the vaccine. Participants were then asked about their intentions to vaccinate under cost or no-cost conditions.

RESULTS

Women who read that the vaccine protects only against cervical cancer had significantly higher intentions to vaccinate themselves when the vaccine was available at little or no cost compared with women who read alternate versions of the descriptive paragraph, F(2,325) = 5.74, p = 0.004.

CONCLUSIONS

How the HPV vaccine is framed may affect vaccination intentions under certain conditions. Women may be more receptive to the vaccine if it is framed as a cervical cancer prevention tool rather than a sexually transmitted infection (STI) prevention tool.

Effectiveness and cost effectiveness of human papillomavirus vaccine: a systematic review

The recent approval of human papillomavirus (HPV) vaccine means that decision makers need information beyond that available from randomized clinical trials to recommend funding for this vaccination programme. Modelling and economic studies have addressed some of those information needs. We conducted a qualitative systematic review to summarize the existing data. Review articles were obtained from an extensive literature search on studies using mathematical modelling (either a Markov or transmission dynamic model) to determine the effectiveness or cost effectiveness of an HPV vaccine compared with the current cytology-based Pap smear screening programme. A total of 21 studies (but 22 models) were included in the review after being assessed for methodological quality. All of the included studies had used a mathematical model to determine the effectiveness of an HPV vaccine, whilst 13 had also conducted a cost-effectiveness analysis. Although the studies used different model structures, baseline parameters and assumptions, all studies showed that vaccination would decrease rates of HPV infection, precancerous lesions and cervical cancer. Studies had a consistent message with respect to cost effectiveness: a female-only vaccination programme is cost effective compared with the current cytology-based Pap smear screening programme, while the cost effectiveness of a male and female vaccination programme is generally not cost effective compared with female-only vaccination.

Reductions in human papillomavirus-disease resource use and costs with quadrivalent human papillomavirus (types 6, 11, 16, and 18) recombinant vaccination: the FUTURE Study Economic Evaluation

OBJECTIVE

To examine the short-term impact of quadrivalent human papillomavirus (HPV) (types 6/11/16/18) recombinant vaccination upon HPV disease-related health-care resource utilization and costs among young women.

METHODS

We analyzed data from a randomized clinical trial comparing quadrivalent vaccination to placebo, among women (N = 7861) primarily 16 to 23 years of age at enrollment. HPV disease episodes, health-care resource utilization and costs associated with cervical, vaginal, and vulvar precancers, and anogenital warts were analyzed over a period of 2.5 years among women, regardless of baseline HPV status.

RESULTS

Overall, there was a 25.9% (P < 0.001) reduction in total HPV disease-related health-care costs among women receiving vaccine versus placebo (absolute reduction $3939 per 100 trial enrollees). We observed similar overall reductions in HPV-disease episodes and resource utilization. There was a statistically significant reduction in HPV 6/11-related disease episode costs of 65.1% ($1837 per 100), and a reduction of 51.4% ($1781 per 100) in HPV 16/18-related episode costs.

CONCLUSIONS

Quadrivalent HPV vaccination can reduce HPV disease events, resource use and costs when administered to a broad population of young women 16 to 23 years of age. Prevention of HPV types 6 and 11 yielded similar value in terms of HPV disease cost offsets, compared to protection against HPV 16 and 18, during the years initially after vaccination. Over the short-term, costs of vaccination exceed cost offsets associated with prevention of HPV disease; however, quadrivalent HPV vaccination has previously been shown to be cost-effective in the longer term, when fully accounting for health benefits and cost offsets.

Structural differences among cost-effectiveness models of human papillomavirus vaccines

In this article we compare previously published cost-effectiveness studies of human papillomavirus (HPV) vaccines along a defined subset of key model structural assumptions relating to HPV infection and disease, cervical cancer screening and HPV vaccination. For each structural aspect examined, we summarize assumptions from each study, provide a critical review and discuss the impact upon results. Considerable variation was observed across HPV vaccine cost-effectiveness models in a number of influential assumptions. Holding constant factors for which current data are lacking, the combined impact of assumptions made for the remaining parameters examined would appear to tend toward underestimation of the cost-effectiveness of HPV vaccination within existing studies. However, uncertainty concerning parameters, such as the duration of vaccine protection and acquired immunity following HPV infection, and the relationship between age and HPV virulence, complicates precise estimation of the cost-effectiveness of HPV vaccination and rigorous evaluation of the validity of existing modeling results.

Seroepidemiology of human papillomavirus type 11 in the United States: results from the third National Health And Nutrition Examination Survey, 1991--1994

OBJECTIVES

The national seroprevalence of the nononcogenic human papillomavirus (HPV) type 11, one of the types targeted by the quadrivalent HPV vaccine, has not been evaluated in the United States. The objectives of this study were to estimate the national seroprevalence and evaluate predictors of HPV-11 seropositivity.

STUDY DESIGN

We tested serum samples for HPV-11 antibodies and analyzed questionnaire data from the second phase of the National Health and Nutrition Examination Survey III, 1991--1994. Seroprevalence estimates were weighted to represent the US population.

RESULTS

: Overall seroprevalence of HPV-11 infection was 4.7%. Seroprevalence was significantly higher among females (5.7%) than among males (3.6%). Independent predictors of HPV-11 seropositivity included sex, race/ethnicity, lifetime number of sex partners, education, and HPV-16 seropositivity.

CONCLUSION

This study represents the most comprehensive picture of HPV-11 infection in the United States to date, and provides baseline data on the prevalence of HPV-11 before availability of the quadrivalent HPV vaccine.

Behavior in early adolescence and risk of human papillomavirus infection as a young adult: results from a population-based study

OBJECTIVE

The goal of this study was to determine the utility of a risk factor-based approach to human papillomavirus catch-up vaccination.

METHODS

Data from waves I and III of the National Longitudinal Study of Adolescent Health were examined to determine the association between adolescent characteristics and future human papillomavirus infection. Analysis was restricted to 3181 female subjects who were >12 years of age when risk factors were assessed in wave I (1994-1995) and who underwent human papillomavirus testing as young adults in wave III (2001-2002). The main outcome of interest was a positive test result for >or=1 of 4 human papillomavirus types (human papillomavirus-6, -11, -16, or -18) targeted by the human papillomavirus vaccine currently available in the United States. Separate analyses were performed for sexually active and virginal adolescents. Poststratification sampling weights were used to generate nationally representative estimates.

RESULTS

Although nearly one half (43%) of the female adolescents were sexually active in wave I, adolescent sexual activity status was not associated with future detection of vaccine-specific human papillomavirus infection. Furthermore, for both virginal and sexually active adolescents, none of the assessed risk factors was associated with increased odds of future vaccine-specific human papillomavirus infection in multivariate models. Similar results were obtained when all high-risk human papillomavirus types were assessed as the outcome measure.

CONCLUSIONS

Behavioral risk factors assessed during adolescence are inadequate predictors of future infection with vaccine-type human papillomavirus. A risk factor-based approach to human papillomavirus catch-up vaccination is unlikely to be an effective implementation strategy.

A systematic review of the prevalence and attribution of human papillomavirus types among cervical, vaginal, and vulvar precancers and cancers in the United States

OBJECTIVES

To describe prevalence and estimated attribution of human papillomavirus (HPV) types in U.S. cervical, vaginal, and vulvar precancers and cancers.

METHODS

U.S. studies reporting HPV typing for cervical intraepithelial neoplasia (CIN), vulvar intraepithelial neoplasia (VIN), and vaginal intraepithelial neoplasia (VaIN) and/or invasive cancers of those sites were gathered from the PubMed database (http://www.ncbi.nlm.nih.gov/sites/entrez/). Selected studies had PCR testing data for > or =10 cases for a disease endpoint. Analytic methods augmented prior reviews of cervical disease with an updated and expanded analysis (including vulvar and vaginal disease), new selection criteria for specimens, and adjustment for histologic type, where possible, among pooled cancer cases. In addition, for analyses of estimated attribution of HPV types, we incorporated accounting methods for lesions infected with multiple HPV types.

RESULTS

Data from 22 U.S. studies meeting review eligibility criteria were tabulated. Following adjustment for the presence of multiple HPV types in a single specimen, the top two HPV types contributing to disease were CIN 1 (HPV 16/66; 15.3%), CIN 2/3 (HPV 16/31; 61.9%), cervical cancer (HPV 16/18; 79.2%), VIN 1 (HPV 6/11; 41.7%), VIN 3 (HPV 16/18; 84.0%), vulvar cancer (HPV 16/33; 55.5%), VaIN 3 (HPV 16/18; 65.1%), and vaginal cancer (HPV 16/18; 72.7%).

CONCLUSIONS

The HPV type distribution and proportion of cases testing positive for any HPV type were observed to vary among U.S. cervical, vulvar, and vaginal neoplasias and by grade of disease. Adjustment for the presence of multitype HPV infections can have an important effect on the estimated attribution of HPV types to disease, particularly for types other than HPV 16.

Seroprevalence of 34 human papillomavirus types in the German general population

The natural history of infections with many human papillomavirus (HPV) types is poorly understood. Here, we describe for the first time the age- and sex-dependent antibody prevalence for 29 cutaneous and five mucosal HPV types from 15 species within five phylogenetic genera (alpha, beta, gamma, mu, nu) in a general population. Sera from 1,797 German adults and children (758 males and 1,039 females) between 1 and 82 years (median 37 years) were analysed for antibodies to the major capsid protein L1 by Luminex-based multiplex serology. The first substantial HPV antibody reactions observed already in children and young adults are those to cutaneous types of the genera nu (HPV 41) and mu (HPV 1, 63). The antibody prevalence to mucosal high-risk types, most prominently HPV 16, was elevated after puberty in women but not in men and peaked between 25 and 34 years. Antibodies to beta and gamma papillomaviruses (PV) were rare in children and increased homogeneously with age, with prevalence peaks at 40 and 60 years in women and 50 and 70 years in men. Antibodies to cutaneous alpha PV showed a heterogeneous age distribution. In summary, these data suggest three major seroprevalence patterns for HPV of phylogenetically distinct genera: antibodies to mu and nu skin PV appear early in life, those to mucosal alpha PV in women after puberty, and antibodies to beta as well as to gamma skin PV accumulate later in life.

Cost-effectiveness of human papillomavirus vaccination in the United States

Results of a simplified model were consistent with published studies based on more complex models when key assumptions were similar.

We describe a simplified model, based on the current economic and health effects of human papillomavirus (HPV), to estimate the cost-effectiveness of HPV vaccination of 12-year-old girls in the United States. Under base-case parameter values, the estimated cost per quality-adjusted life year gained by vaccination in the context of current cervical cancer screening practices in the United States ranged from $3,906 to $14,723 (2005 US dollars), depending on factors such as whether herd immunity effects were assumed; the types of HPV targeted by the vaccine; and whether the benefits of preventing anal, vaginal, vulvar, and oropharyngeal cancers were included. The results of our simplified model were consistent with published studies based on more complex models when key assumptions were similar. This consistency is reassuring because models of varying complexity will be essential tools for policy makers in the development of optimal HPV vaccination strategies.

Circumcision and human papillomavirus infection in men: a site-specific comparison

BACKGROUND

Lack of circumcision has been identified as a risk factor for male genital human papillomavirus (HPV) infection, although this association has not been consistently supported.

METHODS

Specimens for HPV testing were collected from a cohort of 379 (primarily heterosexual) adult males. HPV prevalence in the glans penis and coronal sulcus, penile shaft, scrotum, semen, and urine was compared by circumcision status.

RESULTS

Overall, HPV DNA prevalence ranged from 6% in semen to 52% in the penile shaft. The prevalence of any HPV infection in the glans/corona was significantly higher in uncircumcised men (46%) than in circumcised men (29%) (odds ratio [OR], 1.96 [95% confidence interval (CI), 1.02-3.75], adjusted for demographic characteristics and sexual history). Uncircumcised men also had an increased risk of oncogenic HPV infection (adjusted OR, 2.51 [95% CI, 1.11-5.69]) and infection with multiple HPV types (adjusted OR, 3.56 [95% CI, 1.50-8.50]). Among uncircumcised men, HPV prevalence in the foreskin (44%) was comparable to that in the glans/corona, and type-specific positivity was observed between the 2 sites (kappa=0.52).

CONCLUSIONS

Uncircumcised men have an increased risk of HPV infection, including with oncogenic HPV, specifically localized to the glans/corona, possibly because of its proximity to the foreskin, which may be particularly vulnerable to infection.

Adding a quadrivalent human papillomavirus vaccine to the UK cervical cancer screening programme: A cost-effectiveness analysis

BACKGROUND

We assessed the cost-effectiveness of adding a quadrivalent (6/11/16/18) human papillomavirus (HPV) vaccine to the current screening programme in the UK compared to screening alone.

METHODS

A Markov model of the natural history of HPV infection incorporating screening and vaccination was developed. A vaccine that prevents 98% of HPV 6, 11, 16 and 18-associated disease, with a lifetime duration and 85% coverage, in conjunction with current screening was considered.

RESULTS

Vaccination with screening, compared to screening alone, was associated with an incremental cost-effectiveness ratio of pound21,059 per quality adjusted life year (QALY) and pound34,687 per life year saved (LYS). More than 400 cases of cervical cancer, 6700 cases of cervical intraepithelial neoplasia and 4750 cases of genital warts could be avoided per 100,000 vaccinated girls. Results were sensitive to assumptions about the need for a booster, the duration of vaccine efficacy and discount rate.

CONCLUSION

These analyses suggest that adding a quadrivalent HPV vaccine to current screening in the UK could be a cost-effective method for further reducing the burden of cervical cancer.

Appropriate Use of Cervical Cancer Vaccine

Human papillomavirus (HPV) is a necessary, though not sufficient, cause of cervical cancer. Two vaccines have been developed that prevent two HPV types associated with 70% of cervical cancers. One of the vaccines (a quadrivalent vaccine) also prevents two HPV types associated with 90% of genital warts. Both HPV vaccines have shown very good efficacy and safety. This review summarizes the guidelines for use of the quadrivalent vaccine published by the Advisory Committee on Immunization Practices, presents data on vaccine efficacy and safety, and gives an overview of the findings of cost-effectiveness studies. In addition, we summarize the research on the attitudes of parents and health care providers toward HPV vaccine and critically evaluate controversial and challenging issues surrounding HPV vaccination, including concerns about sexual disinhibition and potential obstacles to vaccine distribution and uptake.

Human papillomavirus vaccine legislation in Kentucky: a policy analysis

The purpose of this article is to discuss the problem of cervical cancer, examine policy solutions, and analyze factors that contributed to the failure of human papillomavirus (HPV) vaccine requirement legislation in Kentucky. During 2007, a Kentucky representative introduced legislation that would require HPV vaccination for all middle-school girls but allow parents to opt out for any reason. Evidence suggests that an HPV school requirement law would result in more Kentucky children being vaccinated than if there were no requirement law. However, this policy solution faced multiple factors that inhibited its ability to survive. Future proponents of HPV vaccine school requirement legislation can draw implications from Kentucky's experience. By building public support, undergoing a softening up period, and presenting a united, vocal front, proponents may be more likely to pass HPV vaccine legislation in the future.

Human papillomavirus infection: epidemiology and pathophysiology

More than 120 different types of the human papillomavirus (HPV) have been isolated; >40 of these types infect the epithelial lining of the anogenital tract and other mucosal areas. In the majority of individuals, HPV infections are transient and asymptomatic with most new infections resolving within 2 years. Epidemiological data from the U.S. National Health and Nutrition Examination Survey determined that the prevalence of HPV infection in a representative sample of women was highest in those aged 20-24 years (44.8%). HPV infection has been firmly established as the primary cause of cervical cancer. It is not clearly understood why HPV infections resolve in certain individuals and result in cervical intraepithelial neoplasias in others, but several factors are thought to play a role; including individual susceptibility, immune status and nutrition, endogenous and exogenous hormones, tobacco smoking, parity, co-infection with other sexually transmitted agents such as HIV, herpes simplex virus type 2 and Chlamydia trachomatis as well as viral characteristics such as HPV type, concomitant infection with other types, viral load, HPV variant and viral integration. Worldwide, pooled data from case-control studies indicated that HPV DNA could be detected in 99.7% of women with histologically confirmed squamous cell cervical cancer compared with 13.4% of control women. Both HPV infection and cervical cancer are associated with a substantial economic burden. Pharmacoeconomic data from the United States indicate that HPV infection and HIV were associated with similar total direct medical costs, and HPV infection was more costly than genital herpes and hepatitis B combined in the 15-25 age group. Furthermore, false-negative pap smears from women with precancerous lesions are among the most frequent reasons for medical malpractice litigation in the United States.

HPV vaccine efficacy in preventing persistent cervical HPV infection: a systematic review and meta-analysis

INTRODUCTION

We performed a pooled analysis of randomised clinical trials (RCT) on HPV vaccine efficacy in preventing cervical persistent infection.

METHODS

We carried out a bibliographic search on electronic databases and we selected RCT to perform the meta-analyses.

RESULTS

We selected five studies. The first meta-analysis, including all studies, showed an important reduction of the risk of infection from HPV 16 in vaccinated cohort [RR 0.10 (95% CI: 0.07-0.15)]. The second and third meta-analyses, including only studies on bivalent and tetravalent vaccines, showed a RR of 0.13 (95% CI: 0.09-0.20) for HPV 16 infections and a RR of 0.22 (95% CI: 0.13-0.38) for HPV 18 ones.

DISCUSSION

HPV vaccine efficacy in preventing persistent infection is high but there is the need for further studies on the duration of immunization and long-term vaccine efficacy.

Estimating the number needed to vaccinate to prevent diseases and death related to human papillomavirus infection

BACKGROUND

A vaccine against human papillomavirus (HPV) types 6, 11, 16 and 18 is now licensed for use in Canada and many other countries. We sought to estimate the number needed to vaccinate to prevent HPV-related diseases and death.

METHODS

A cohort model of the natural history of HPV infection was developed. Model simulations were based on 209 different parameter sets that reproduced Canadian HPV type-specific data for infection, cervical intraepithelial neoplasia, cervical cancer and genital warts. The number needed to vaccinate was calculated as the number of women who would need to be vaccinated to prevent an HPV-related event during their lifetime.

RESULTS

Among 12-year-old girls, we estimated that the number needed to vaccinate to prevent an episode of genital warts would be 8 (80% credibility interval [CrI] 5-15) and a case of cervical cancer 324 (80% CrI 195-757). These estimates were based on the assumption that the vaccine procures lifelong protection and that its efficacy is 95%. If vaccine protection is assumed to wane at 3% per year, the predicted number needed to vaccinate would increase to 14 (80% CrI 6-18) and 9080 (80% CrI 1040-does not prevent), respectively. The latter number would be greatly reduced with the addition of a booster dose, to 480 (80% CrI 254-1572).

INTERPRETATION

Our model predictions suggest that vaccination with the currently available HPV vaccine may significantly reduce the incidence of genital warts, cervical intraepithelial neoplasia and cervical cancer. However, the benefits (particularly in terms of cervical cancer reduction) are highly dependent on the duration of vaccine protection, on which evidence is currently limited.

Impact of the human papilloma vaccine on cervical cancer

During the last decade, research progress on cervical cancer has elucidated the role of human papilloma virus (HPV) in the pathogenesis of cervical cancer. Clinical trials on the viral-like particle HPV vaccines have good safety profiles and promising efficacy in preventing genital warts, cervical neoplasia, and cervical cancer. The implementation of the HPV vaccine is a tremendous milestone in our effort toward preventing cervical cancers. However, screening programs will continue to serve as a critical component in prevention due to the limitations of the current vaccines. The greatest impact in cervical cancer incidence worldwide requires improved health care access to underserved areas. Advances are needed to develop single-dose, heat-stable, needle-free, and affordable formulations of the HPV vaccine to overcome the socioeconomic barriers associated with this disease.

Pediatrician knowledge and attitudes regarding human papillomavirus disease and its prevention

Between 1 September and 8 October 2006, we used a self-administered, anonymous questionnaire in order to evaluate knowledge and attitudes regarding HPV disease and its prevention in a nationally representative sample of Italian pediatricians. Three hundred and eleven of the 400 enrolled physicians (175 primary care pediatricians, 160 hospital pediatricians and 65 residents in pediatrics) returned completed surveys (227 females; mean age+/-standard deviation, 45.3+/-11.61 years). The results showed a lack of knowledge concerning HPV disease and its prevention, with marginal differences between the subgroups, even though the majority would recommend HPV vaccination. These findings highlight an urgent need to improve pediatrician information in order to ensure the optimal implementation of HPV vaccination, and the adequate acceptability of HPV vaccines to adolescents and their parents.

Progression and regression of incident cervical HPV 6, 11, 16 and 18 infections in young women

BACKGROUND

We describe type-specific progression, regression and persistence of incident human papillomavirus (HPV)-6-11-16 and -18 infections, along with type distribution in cervical intra-epithelial neoplasia (CIN) lesions.

METHODS

The study population consisted of 16-23 year-old women undergoing Pap testing and cervical swab polymerase chain reaction testing for HPV DNA at approximate 6 month intervals for up to 4 years in the placebo arm of a clinical trial of an HPV 16-vaccine. HPV types in incident infections were correlated with types in lesion biopsy specimens.

RESULTS

56.7% of CIN-1 and nearly one-third of CIN-2/3 lesions following incident HPV-6-11-16 or -18 infections did not correlate with the incident infection HPV type. Cumulative 36-month progression rates to CIN-2/3 testing positive for the relevant HPV type were highest for HPV-16 infections (16.5%), followed by HPV-18 (8.2%). Overall, 26.0% of CIN-1, 50.0% of CIN-2 and 70.6% of CIN-3 biopsies tested positive for HPV-6-11-16-18 infections.

CONCLUSION

Women with a given HPV type may often be co-infected or subsequently infected with other types which may lead to subsequent cervical lesions. This issue has been addressed in this study reporting data for the natural history of HPV-6-11-16 and -18 infections and is a relevant consideration in designing future studies to evaluate the incidence/risk of CIN following other type-specific HPV infections.

Assessing the introduction of universal human papillomavirus vaccination for preadolescent girls in The Netherlands

A persistent infection with human papillomavirus (HPV) is a prerequisite for the development of cervical cancer. Clinical trials with HPV-vaccines have been very successful in preventing persistent HPV16/18 infections, the two most oncogenic HPV-genotypes. We assessed the introduction of universal HPV-vaccination for preadolescent girls in the Dutch National Immunization Programme. Long-term vaccine efficacy, the need and extent of a catch-up programme for young women, and the impact of vaccination on the cervical cancer screening programme are major unresolved issues. Preliminary conservative estimates (80% vaccine efficacy and no effects on the screening programme, transmission rate, non-cervical cancer incidence, and cross protection) predict an acceptable cost-effectiveness ratio for universal vaccination of preadolescent girls.

Population-based study of human papillomavirus infection and cervical neoplasia in Athens, Greece

The aim of our study is to describe the prevalence of the different HPV types in women with pre-neoplastic lesions of the cervix in Greece. Cervical scrapes from 841 women were obtained for both cytological evaluation and analysis for the presence of HPV DNA. PCR was performed on specimens from these 841 women. The Pap test results were normal or showed benign cellular changes in 45.8% of the women, atypical squamous cells of undetermined significance (ASCUS) in 23.2%, low-grade squamous intra-epithelial lesion (LSIL) in 27.9% and high-grade squamous intra-epithelial lesion (HSIL) in 3.1%. HPV DNA was demonstrated in 23.6% of cytologically normal women. We detected HPV in 60% of the total samples. Of these, HPV-16 was the most common HPV DNA detected. Interestingly, HPV-58 was inversely correlated with positive cytological findings. A clear pattern of decreasing prevalence of HPV with age was also observed. Our results indicate that HPV infections, especially those with HPV-16, represent a significant public health concern in Greece.

The potential cost-effectiveness of prophylactic human papillomavirus vaccines in Canada

AIM

Clinical trials have shown prophylactic human papillomavirus (HPV) vaccines to be effective against infection and disease. We examined whether HPV vaccination has the potential to be cost-effective.

METHODS

A cohort model of the natural history of HPV was developed, which fits simultaneously Canadian age and type-specific data for infection, cervical intraepithelial neoplasia, cervical cancer (CC) and genital warts (GW). Quality-Adjusted Life-Years (QALYs) lost and costs were estimated using data from the literature.

RESULTS

Vaccinating 12-year-old girls (efficacy=95%, no waning, cost/course=CAN$ 400) against HPV-16/18 and HPV-6/11/16/18 is estimated to cost the health provider CAN$ 31,000 (80%CrI: 15,000-55,000) and CAN$ 21,000 (80%CrI: 11,000-33,000) per QALY-gained, respectively. Results were most sensitive to age at vaccination, duration of vaccine protection, vaccine cost and QALY-lost due to GW, and were least sensitive to the medical costs.

CONCLUSION

Vaccinating adolescent girls against HPV is likely to be cost-effective. The main benefit of vaccination will be in reducing CC mortality. However, unless screening is modified, the treatment costs saved through vaccination will be insignificant compared to the cost of HPV immunization.

Incidence and Duration of Cervical Human Papillomavirus 6, 11, 16, and 18 Infections in Young Women: An Evaluation from Multiple Analytic Perspectives

OBJECTIVE

To estimate the incidence and duration of cervical human papillomavirus (HPV)-6, HPV-11, HPV-16, and HPV-18 infections in a population of young American women.

METHODS

The study population consisted of U.S. women who at baseline were 16 to 23 years of age, reported zero to five lifetime sexual partners, never having been pregnant, and never having had a prior abnormal Papanicolaou test and were enrolled in the placebo arm of a randomized multicenter clinical trial of a HPV-16 L1 virus-like particle vaccine. Women underwent type-specific endocervical/ectocervical swab HPV DNA testing at approximately 6-month intervals for up to 48 months of follow-up. To contribute person-time in the analyses of type-specific HPV incidence, a woman must have had at least three satisfactory swab specimens available and been negative for the relevant HPV type (HPV-6, HPV-11, HPV-16, or HPV-18) on her first two trial swabs. The duration of incident HPV infections was estimated using Kaplan-Meier survival analysis methods.

RESULTS

Person-years of exposure ranged by type-specific analysis from 2,645 to 3,188, with an incidence rate per 100 person-years of 3.6 for HPV-6, 0.4 for HPV-11, 5.4 for HPV-16, and 2.1 for HPV-18. With censoring at the time of treatment for cervical intraepithelial neoplasia, where done, the mean duration of incident infections was 9.3, 8.4, 18.2, and 16.4 months, respectively, for HPV-6 (n = 103), HPV-11 (n = 13), HPV-16 (n = 142), and HPV-18 (n = 62). When the duration of HPV infections was truncated at the time of cervical intraepithelial neoplasia detection (any grade), where applicable, mean duration figures were 8.4, 8.1, 14.0, and 15.1 months for HPV-6, HPV-11, HPV-16, and HPV-18 infections, respectively.

CONCLUSIONS

Previous studies of the mean duration of cervical HPV infection have been based on prevalent infections and/or featured relatively short duration of follow-up. This study tested women for HPV infection over a period of up to 48 months and observed a mean duration of incident HPV-16/HPV-18 infections approximately twice that of HPV-6/HPV-11.

Local And Systemic Human Papillomavirus Type 6b-Specific Cellular Immune Responses in Patients with Recurrent Genital Warts

Anogenital warts are a common clinical manifestation of genital infection with human papillomavirus type 6b (HPV-6b). Accumulating data indicate that an effective cellular immune response is required for the control of HPV infections. However, in a minority of patients there is a high rate of recurrence of wart lesions. We report the characterization of both local and systemic HPV-specific cellular immune responses in three patients with a history of recurrent genital warts. Although the patients had chronic recurrent wart lesions, we have shown that each had both detectable intralesional and peripheral HPV-specific T lymphocytes. Interestingly, the lesion-infiltrating T cells were specific for only one HPV antigen, focusing on only a few epitopes. Conversely, the T cells derived from peripheral blood recognized a broader range of HPV antigens. The characteristics of the HPV-specific cellular immunity that we have shown in these patients may be indicative of a failure to mount an effective response against the virus. This would be consistent with the chronic nature of the disease in these specific individuals. These observations could be relevant to the design and immunomonitoring of immunotherapeutic vaccines for persistent HPV infections.

A content analysis of news coverage of the HPV vaccine by U.S. newspapers, January 2002-June 2005

Genital Human Papillomavirus (HPV) is the most common sexually transmitted infection in the United States. Of the 100 HPV types, HPV type 16 and HPV type 18 have been demonstrated to cause cervical cancer. Two pharmaceutical manufacturers have developed and tested HPV vaccines and are applying to the FDA for licensure. This research describes the content of HPV vaccine information contained in news articles. The Lexis-Nexis database was used to identify 25 articles on HPV that were published in 285 U.S. newspapers from January 1, 2003 to June 17, 2005. The coding schema captured information about the news event and source, as well as HPV and cervical cancer, transmission, vaccine, potential impact of the vaccine, and its relationship to PAP tests. The content analysis revealed that the news coverage of HPV vaccine provides information on the experimental status and efficacy of the vaccine, explains link between HPV and cervical cancer, and reports the manufacturers by name, as well as relies on them for a news source. Detailed information about HPV, however, was frequently missing which could lead to an incomplete picture or lack of understanding of the complexity of HPV and cervical cancer. As a major source of medical information, the media can be particularly important in educating policy makers and the general public about new scientific advances. Public health officials may wish to collaborate with journalists, health educators, healthcare providers, and women's health advocates to ensure that future educational initiatives explain the complexity of the association of HPV and cervical cancer and to stress the importance of continued cervical cancer screening.

Imiquimod et autres immunomodulateurs en gynécologie

Immunomodulators have been used for some time in various medical specialities, but have only recently been used in gynaecology. The first drug in this therapeutic class, Immiquimod (Aldara), has been shown to be effective in treating lesions induced by Human Papillomavirus (HPV) such as genital warts or cervical and vulvar dysplasia, by stimulating the immune system of an infected individual. Thanks to its ease of use and its few side effects, Imiquimod would appear to be, in the future, the treatment of choice for these types of viral infections, alone or in association with therapeutic vaccines or physical abative therapies as a prevention of relapses. This review aims at summarizing and clarifying the mechanism of action of the different immunomodulators, their indications and their effectiveness in gynecologic practice.

Vacuna frente al virus del papiloma humano: un nuevo reto para el pediatra

Human papillomavirus (HPV) infections are the most common sexually transmitted infections in the world. This infection is a necessary cause of cervical cancer, has been related to other forms of anogenital, airway and digestive cancers, and also causes anogenital warts. The recent advances in HPV prophylactic vaccines and their imminent commercial availability will post a new challenge to pediatricians: the indication and administration of these vaccines for the prevention of HPV infection, and consequently, of cervical cancer and other HPV-related diseases. The present article reviews the essentials of HPV infection, its relationship with cervical cancer, the advances in prophylactic HPV vaccines, and the role of the pediatrician in this context.

Frequency of antibodies against E4 and E7 from human papillomavirus type 16 in Mexican soldiers

The high prevalence of HPV in men's genitalia and the low frequency of virus-associated lesions gave rise to questions on the influence of infection-site on the HPV antibody profile. In a cross-sectional study, HPV infection in penis and urethra, and serum antibodies against HPV-16 E4 and E7 proteins were evaluated in 288 Mexican soldiers. The results showed that HPV prevalence was 31% (51% in penis, 11% in urethra and 38% in both sites), while 47% were multiple infections. Overall, seroprevalence was 13% for anti-E4 antibodies and 6% for anti-E7. However, the highest prevalence of anti-E4 antibodies was observed in men with HPV infection in urethra (30%), while for E7 antibodies, the highest prevalence (10%) was found in men who tested positive for HPV in penis. The prevalence of IgG and IgA anti-E4 was related to HPV-16 urethral infection, while detection of HPV-16 in penis was related to IgG anti-E7 prevalence. In conclusion, the high-risk sexual behavior observed in this population might be responsible for high HPV prevalence and multiple infections. However, the seroprevalence of E4 and E7 was similar to that observed in healthy Mexican women. These results suggest that the humoral immune response against HPV infection in men differs, depending on the site of infection.