Use of the nonavalent HPV vaccine in individuals previously fully or partially vaccinated with bivalent or quadrivalent HPV vaccines

Human Papillomavirus Vaccination in Pediatric, Adolescent, and Young Adult Cancer Survivors-Opportunity to Address Gaps in Cancer Prevention and Survivorship

The risks of secondary cancers associated with human papillomavirus (HPV) infection are as much as three times higher for survivors of pediatric, adolescent, and young adult cancer (PYAC) compared to the general population. Despite this, HPV vaccination rates among PYAC survivors remain low. Whereas pediatric oncology providers endorse HPV vaccination of PYAC survivors, many lack the resources or opportunities to intervene. The responsibility of HPV vaccination, therefore, falls to primary care providers and practices. This article provides an overview of the challenges with HPV vaccination that are distinct to PYAC survivors and discusses potential strategies to increase HPV vaccine coverage in this population.

Cervical Intraepithelial Neoplasia 3 (Cervical Intraepithelial Neoplasia 3/High-Grade Squamous Intraepithelial Lesion) in Human Papillomavirus-Vaccinated Women-Results From a Tertiary Referral Center

OBJECTIVE

High-grade cervical intraepithelial neoplasia (CIN 3) still develops in some vaccinated women despite established effectiveness of prophylactic human papillomavirus (HPV) vaccination. The purpose of this study was to define characteristics of women with CIN 3 after HPV vaccination referred to a gynecological dysplasia unit.

MATERIALS AND METHODS

Retrospective analysis of HPV-vaccinated women with CIN 3 in a single German center. Between July 2018 and September 2020, 791 women were referred to our university hospital-based dysplasia unit for colposcopic evaluation of abnormal cytological findings. Human papillomavirus vaccination status was retrieved. Human papillomavirus typing was performed in lesional biopsies and cervical swabs.

RESULTS

Nine women were identified who had previously been vaccinated with the quadrivalent HPV vaccine (Q-HPV) and were diagnosed with histologically confirmed CIN 3/high-grade squamous intraepithelial lesion. The Q-HPV had been administered between 12 and 28 years of age and 1-13 years before CIN 3 diagnosis. Nine different high-risk (HR)-HPV types were found in the CIN 3 biopsies, 6 monoinfections (twice HPV 16, once HPV 18, HPV 31, HPV 52, HPV 58, respectively) and 3 dual infections (HPV 33 + 52, HPV 51 + 52, HPV 53 + 66). Seven of these 9 HR-HPV types are not covered by Q-HPV, but only 2 CIN 3 lesions carried HR-HPV types not included in the nonavalent HPV vaccine.

CONCLUSIONS

It is important to implement vaccination recommendations and administer HPV vaccination as early as possible in HPV-naive individuals. Because not all HR-HPV types are covered by the available HPV vaccines, other types may still cause CIN 3/high-grade squamous intraepithelial lesion. This requires further screening after vaccination, especially in women who were previously vaccinated with the bivalent or the quadrivalent HPV vaccine.

Prevalence of genital human papillomavirus by age and race/ ethnicity among males

BACKGROUND

Genital and oral cancers are often caused by human papillomavirus (HPV) types that can be prevented through HPV vaccination. Since HPV is sexually transmitted, knowledge of penile prevalence of vaccine-type HPV among US males can help predict potential disparities in these cancers. This study examines penile HPV prevalence by age and race/ethnicity among males.

METHODS

This study was a secondary analysis of publicly available data from the National Health and Nutrition Examination Survey (NHANES). Using data from penile swab samples collected from males between 2013 and 2016, the prevalence of 4vHPV and 9vHPV vaccine types was examined across age groups and by race/ethnicity. Logistic regression models adjusting for demographics, sexual behavior and circumcision were examined to determine whether associations remained after accounting for confounders.

RESULTS

Among 2,548 males evaluated, HPV infection prevalence differed by race/ethnicity with black males exhibiting a higher prevalence of HPV. Examination of 4vHPV type prevalence by age group showed that 18-26 year old males had a lower prevalence compared to older age groups. After controlling for confounders, 4vHPV prevalence was only significantly elevated among 27-34-year old males, those who were single, and males with 3+ lifetime sex partners. In adjusted models, 9vHPV type prevalence remained elevated among black males compared to white males.

CONCLUSION

Variations in 9vHPV type prevalence between blacks and whites indicate future disparities in HPV-related genital cancers may continue in the US during the next decade. Revaccinating certain populations with the 9vHPV vaccine may be appropriate to help mitigate this.

A co-infection model for HPV and syphilis with optimal control and cost-effectiveness analysis

A co-infection model for human papillomavirus (HPV) and syphilis with cost-effectiveness optimal control analysis is developed and presented. The full co-infection model is shown to undergo the phenomenon of backward bifurcation when a certain condition is satisfied. The global asymptotic stability of the disease-free equilibrium of the full model is shown not to exist when the associated reproduction number is less than unity. The existence of endemic equilibrium of the syphilis-only sub-model is shown to exist and the global asymptotic stability of the disease-free and endemic equilibria of the syphilis-only sub-model was established, for a special case. Sensitivity analysis is also carried out on the parameters of the model. Using the syphilis associated reproduction number, [Formula: see text], as the response function, it is observed that the five-ranked parameters that drive the dynamics of the co-infection model are the demographic parameter [Formula: see text], the effective contact rate for syphilis transmission, [Formula: see text], the progression rate to late stage of syphilis [Formula: see text], and syphilis treatment rates: [Formula: see text] and [Formula: see text] for co-infected individuals in compartments [Formula: see text] and [Formula: see text], respectively. Moreover, when the HPV associated reproduction number, [Formula: see text], is used as the response function, the five most dominant parameters that drive the dynamics of the model are the demographic parameter [Formula: see text], the effective contact rate for HPV transmission, [Formula: see text], the fraction of HPV infected who develop persistent HPV [Formula: see text], the fraction of individuals vaccinated against incident HPV infection [Formula: see text] and the HPV vaccine efficacy [Formula: see text]. Numerical simulations of the optimal control model showed that the optimal control strategy which implements syphilis treatment controls for singly infected individuals is the most cost-effective of all the control strategies in reducing the burden of HPV and syphilis co-infections.

Progress in Vaccination of Prophylactic Human Papillomavirus Vaccine

The human papillomavirus (HPV) vaccine plays an important role in preventing a series of diseases caused by HPV. Recent studies have shown that as a primary prevention measure, it can considerably prevent HPV infection and HPV-associated cervical cancer. However, studies on the safety, efficacy, and coverage of the HPV vaccine remain insufficient, especially in developing countries. Therefore, in this review, we outlined the recent studies of the HPV vaccine in terms of immunogenicity, safety, efficacy, latest vaccination concepts, and strategies. This review may provide a theoretical basis for use of the HPV vaccine.

[Recommendations in Male HPV from the Portuguese Society of Andrology, Sexual Medicine and Reproduction: Prevention]

The prevention of HPV-related diseases is an important healthcare issue due to its increasing incidence. Primary prevention is most important in males as it avoids initial infection and includes the use of condom, circumcision and vaccination. Primary prevention with vaccination is effective in decreasing HPV-related lesions in women up to 45 years old and the existing data for men comes from the experience from vaccinating women. Although it is the only vaccine that prevents cancer, the worldwide rates of vaccination in males is very low due to lack of information related to efficacy and side effects, lack of recommendation from the treating doctor, price and concern about encouragement of sexual promiscuity.

HPV Vaccination: The Position Paper of the Italian Society of Colposcopy and Cervico-Vaginal Pathology (SICPCV)

Human papillomavirus (HPV) related cervical cancer represents an issue of public health priority. The World Health Organization recommended the introduction of HPV vaccination in all national public programs. In Europe, vaccines against HPV have been available since 2006. In Italy, vaccination is recommended and has been freely offered to all young girls aged 11 years since 2008. Three prophylactic HPV vaccines are available against high- and low-risk genotypes. The quadrivalent vaccine contains protein antigens for HPV 6, 11, 16, and 18. The bivalent vaccine includes antigens for HPV 16 and 18. The nonavalent vaccine was introduced in 2014, and it targets HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. Clinical trials demonstrated the effectiveness of the three vaccines in healthy young women. Likewise, all vaccines showed an excellent safety profile. The bivalent vaccine provides two doses in subjects aged between 9 and 14 years and three doses in subjects over 14 years of age. The quadrivalent vaccine provides two doses in individuals from 9 to 13 years and three doses in individuals aged 14 years and over. The nonavalent vaccine schedule provides two doses in individuals from 9 to 14 years of age and three doses in individuals aged 15 years and over at the time of the first administration. Preliminary results suggest that the HPV vaccine is effective in the prevention of cervical squamous intraepithelial lesions even after local treatment. Given these outcomes, in general, it is imperative to expand the vaccinated target population. Some interventions to improve the HPV vaccine’s uptake include patient reminders, physicians-focused interventions, school-based vaccinations programs, and social marketing strategies. The Italian Society of Colposcopy and Cervico-Vaginal Pathology (SICPCV) is committed to supporting vaccination programs for children and adolescents with a catch-up program for young adults. The SICPCV also helps clinical and information initiatives in developing countries to decrease the incidence of cervico-vaginal and vulvar pathology.

The impact of p16ink4a positivity in invasive vulvar cancer on disease-free and disease-specific survival, a retrospective study

Purpose

To evaluate HPV and p16^ink4a status as prognostic factors in patients with invasive vulvar cancer.

Methods

Retrospective analysis of disease-free (DFS) and disease-specific survival (DSS) of patients with invasive vulvar cancer at a single tertiary care center. Histology, HPV and p16^ink4a status were evaluated in the context of a global multicenter trial. Logistic regression models were performed to identify the impact of p16^ink4a positivity.

Results

135 patients were included in the analysis. 32 (23.7%) showed a p16^ink4a expression of over 25%. Disease-free and disease-specific survival was longer in p16^ink4a positive patients (23 vs. 10 months, p = 0.004, respectively, 29 vs. 21 months, p = 0.016). In multivariate analysis, p16^ink4a positivity was an independent parameter for DFS (p = 0.025, HR: 2.120 (1.100–4.085)), but not for DSS (p = 0.926, HR: 1.029 (0.558–1.901), in contrast to age and tumor stage.

Conclusions

Age and tumor stage negatively affect survival. However, disease-free survival is significantly longer in patients with p16^ink4a positive invasive vulvar cancer.

Uptake of the HPV vaccine among people with and without HIV, cisgender and transgender women and men who have sex with men and with women at two sexual health clinics in Mexico City

Our aim was to better understand Human Papillomavirus (HPV) vaccine acceptance among Mexican adults including people with and without HIV, cisgender men who have sex with men (MSM) or with women (MSW), cisgender and transgender women. A computer-assisted, self-administered questionnaire was completed by healthcare users and participants recruited through community organizations, and the first dose of the quadrivalent HPV vaccine was offered at no cost at a large sexual health clinic in Mexico City, from May to December 2018. Socio-demographic characteristics and factors associated with HPV vaccine acceptance were analyzed using logistic regression.The sample of 1915 participants included 1341 cisgender men (70.9%, 1247 MSM and 94 MSW), 396 (20.7%) cisgender women and 178 (9.3%) transwomen; 615 people (32.1%) were HIV positive. Uptake of the HPV vaccine was higher in men and transwomen (91.5% and 87%, respectively) than among cisgender women (81.8%; p < .001). Cisgender women (OR 0.43, 95%CI 0.30-0.61, p < .05) were less likely to accept HPV vaccination than men. Married/partnered people were less likely to accept HPV vaccination compared to those who were single (OR 0.70, 95%CI 0.51-0.97). People living with HIV were not significantly more likely to accept HPV vaccination (OR 1.7; 95%CI 0.86-1.61).HPV vaccine acceptance was high among adult Mexican study participants; it may be higher than among other Mexican adults given most of these individuals are engaged in care. Modifications will be needed in national and international recommendations on HPV vaccination in adults if healthcare personnel are to recommend the vaccine to the population groups studied.

Dendritic Cells/Macrophages-Targeting Feature of Ebola Glycoprotein and its Potential as Immunological Facilitator for Antiviral Vaccine Approach

In the prevention of epidemic and pandemic viral infection, the use of the antiviral vaccine has been the most successful biotechnological and biomedical approach. In recent times, vaccine development studies have focused on recruiting and targeting immunogens to dendritic cells (DCs) and macrophages to induce innate and adaptive immune responses. Interestingly, Ebola virus (EBOV) glycoprotein (GP) has a strong binding affinity with DCs and macrophages. Shreds of evidence have also shown that the interaction between EBOV GP with DCs and macrophages leads to massive recruitment of DCs and macrophages capable of regulating innate and adaptive immune responses. Therefore, studies for the development of vaccine can utilize the affinity between EBOV GP and DCs/macrophages as a novel immunological approach to induce both innate and acquired immune responses. In this review, we will discuss the unique features of EBOV GP to target the DC, and its potential to elicit strong immune responses while targeting DCs/macrophages. This review hopes to suggest and stimulate thoughts of developing a stronger and effective DC-targeting vaccine for diverse virus infection using EBOV GP.

Methodological issues in a cross-sectional survey on cervical cancer screening using telephone interviews in Sicily (Italy): a SWOT analysis

Objective

A cross-sectional study on knowledge, perceptions, and adherence to cervical cancer screening was conducted using telephone interviews of Sicilian women that were performed in 2016. This study aimed to identify areas that need to be addressed to improve the validity of data collection and to minimize possible biases.

Methods

We performed a qualitative study through SWOT analysis, which is a multidimensional method based on evaluation of Strengths (S), Weaknesses (W), Opportunities (O), and Threats (T) of the research project. The contents of the SWOT forms underwent categorical, inductive, and deductive data analysis using the long table analysis method.

Results

The full availability of an updated address and phone number list was the main organizational aspect to be addressed. Socio-cultural context played a major role for understanding the questions and for acceptability of the topics. In some cases, a family member was a facilitating element, while in others, the family member hindered the interviews. Active involvement of general practitioners was considered essential for success of the interviews.

Conclusions

When performing a cross-sectional survey, organizational aspects and active involvement of general practitioners are crucial in the enrolment phase, regardless of the socio-cultural context.

Immunization Campaigns and Strategies against Human Papillomavirus in Italy: The Results of a Survey to Regional and Local Health Units Representatives

Objective. The study aimed to assess the impact of HPV immunization campaigns organizational aspects, the characteristics of immunization program (vaccination targets and type of offer), and communicative strategies adopted by four Italian administrative regions on vaccination coverage observed. Methods. From November 2017 to March 2018, regional and Local Health Units (LHUs) representatives were invited to complete an online survey including 54 questions evaluating vaccination invite systems, access systems to vaccination centres, reminder and recall systems, and adverse events surveillance. An overall descriptive analysis was conducted. Since observed vaccine coverage (VC) obtained in females (2002-2004 birth cohorts) was lower than objectives fixed by the Italian Ministry of Health, variables were assessed using the national VC mean obtained in the 2003 girls birth cohort as outcome. Results. Twenty-six LHUs belonging to 4 Northern and Southern Italian regions participated in the study. Organizational aspects significantly related to VC lower than the national mean were access to vaccine centres without appointment and parents' reservation as appointment planning system. Recall systems for both the first and the second dose, including the appointment in the invitation letter, the availability of regional immunization registry, and education of healthcare workers on universal HPV immunization strategies, instead, were related to higher VC. As regards preadolescent immunization strategies, both VC obtained in girls and boys were far from the Ministerial goals. Only 20% of LHUs introduced multicohort female strategies while all LHUs adopted copayment targeting both men and women. Immunizations strategies targeting subjects at risk were implemented only in half of participating LHUs. Conclusions. VC observed in participating LHUs are largely lower than the national objectives in all anti-HPV vaccine targets. Both organizational and educational strategies have to be implemented to improve the VC goals.

Recombinant human papillomavirus nonavalent vaccine in the prevention of cancers caused by human papillomavirus

Human papillomavirus (HPV) types 16 and 18 cause 70% of cervical cancer cases globally. The nonavalent HPV vaccine (9vHPV) was licensed in 2014 and protects against the next five most common cancer-causing HPV types (HPV 31/33/45/52/58) after HPV 16/18. Phase III clinical studies have demonstrated high vaccine efficacy (>90%) against cervical, vulvar, and vaginal precancers caused by these additional types, and have shown comparable immunogenicity to the shared genotypes to quadrivalent HPV vaccine (4vHPV). Vaccine efficacy and antibody responses for 9vHPV are found to persist for at least five years while longer-term observational studies are ongoing to monitor long-term vaccine effectiveness. The implementation of 9vHPV has the potential to prevent up to 93% of cervical cancer cases, as well as a significant proportion of other HPV-related anogenital cancers. This review article summarizes the current evidence for 9vHPV in terms of vaccine efficacy against HPV infection and related anogenital precancers, safety, and immunogenicity, as well as discussing the potential impact of this vaccine on the cervical cancer burden globally.

Human papillomavirus vaccination: The ESGO-EFC position paper of the European society of Gynaecologic Oncology and the European Federation for colposcopy

Vaccines against human papillomavirus (HPV) are available in Europe since 2006. They have been highly effective in preventing infection and disease caused by the vaccine types. Clinical efficacy data are available for cervical, vulvovaginal and anal precancer and invasive cervical cancer. Disease reduction is best with early vaccination and a coverage of more than 70%. Gender-neutral vaccination provides direct protection for all men and improves the coverage. A good coverage is followed by herd protection of the unvaccinated men and women. School-based programs appear to be most effective; under the age of 15 years, two doses with an interval of 6-12 months are sufficient. From the age of 15 years, the standard regimen with three doses is recommended. A broad catch-up program for young adult women and men improves the effectiveness. The vaccines are also effective in sexually active women and men with previous but cleared infections. Vaccination in addition to local treatment of HPV-related disease appears to reduce recurrent or subsequent HPV-related disease. Combination of HPV vaccination and screening with HPV testing is the most effective approach to prevention of cervical cancer. The screening intervals may increase in the vaccinated cohorts. The upper age limit for vaccination remains to be evaluated, is country specific and depends on cost-effectiveness. The European Society of Gynaecologic Oncology and the European Federation for Colposcopy strongly support gender-neutral vaccination programs for children and young adolescents, with a catch-up program for young adults.

Human papillomavirus genotype and viral load agreement between paired first-void urine and clinician-collected cervical samples

The performance and acceptability of first-void urine as specimen for the detection of HPV DNA in a Belgian referral population was evaluated using an optimized sample collection and processing protocol. One hundred ten first-void urine and cervical samples were collected from 25- to 64-year-old women who were referred for colposcopy (January-November 2016). Paired samples were analyzed by the Riatol qPCR HPV genotyping assay. Acceptability data were gathered through questionnaires (NCT02714127). A higher high-risk HPV DNA prevalence was observed in first-void urine (n = 76/110) compared to cervical samples (n = 73/110), with HPV31 and HPV16/31 being most prevalent correspondingly. For both any and high-risk HPV DNA, good agreement was observed between paired samples (Cohen's Kappa of 0.660 (95% CI: 0.486-0.833) and 0.688 (95% CI: 0.542-0.835), respectively). In addition, significant positive correlations in HPV copies (per microliter of DNA extract) between paired samples were observed for HPV16 (rs = 0.670; FDR (false discovery rate)-adjusted p = 0.006), HPV18 (rs = 0.893; FDR-adjusted p = 0.031), HPV31 (rs = 0.527; FDR-adjusted p = 0.031), HPV53 (rs = 0.691; FDR-adjusted p = 0.017), and HPV68 (rs = 0.569; FDR-adjusted p = 0.031). First-void urine sampling using a first-void urine collection device was preferred over a clinician-collected cervical sample. And mostly, first-void urine sampling at home was favored over collection at the clinic or the general practitioner's office. First-void urine sampling is a highly preferred, non-invasive method that ensures good agreement in HPV DNA (copies) with reference cervical samples. It is particularly interesting as a screening technique to reach non-participants, and its clinical performance should be further evaluated.

High risk human papillomavirus prevalence and genotype distribution among women infected with HIV in Manaus, Amazonas

BACKGROUND

Human immunodeficiency virus (HIV)-positive women have a high prevalence of human papillomavirus (HPV), and are infected with a broader range of HPV types than HIV-negative women. We aimed to determine the prevalence of cervical cytologic abnormalities, high-risk (HR)-HPV prevalence, type distribution according to the severity of cervical lesions and CD4 cell count and identify factors associated with HR-HPV infection among women living with HIV in Manaus, Amazonas.

METHODS

We enrolled 325 women living with HIV that attended an infectious diseases referral hospital. Each woman underwent a gynecological exam, cervical cytology, HR-HPV detection by Polymerase chain Reaction (PCR) using the BD Onclarity™ HPV Assay, colposcopy and biopsy, when necessary. We assessed the associations between potential risk factors and HR-HPV infection.

RESULTS

Overall, 299 (92.0%) women had a PCR result. The prevalence of HR-HPV- infection was 31.1%. The most prevalent HR-HPV types were: 56/59/66 (32.2%), 35/39/68 (28.0%), 52 (21.5%), 16 (19.4%), and 45 (12.9%). Among the women with HR-HPV infection (n = 93), 43.0% had multiple infections. Women with HPV infection showed higher prevalence of cervical abnormalities than that HPV-negative (LSIL: 22.6% vs. 1.5%; HSIL: 10.8% vs. 0.0%). The prevalence of HR-HPV among women with cytological abnormalities was 87.5% for LSIL and 100.0% for HSIL. Women with CD4 < 200 cell/mm³ showed the highest HR-HPV prevalence (59.3%) although this trend was not statistically significant (p-value = 0.62). The mean CD4 cell count decreased with increasing severity of cervical lesions (p-value = 0.001). The multivariable analysis showed that increasing age was associated with a decreased risk of HR-HPV infection with an adjusted prevalence odds ratio of 0.9 (95.0% CI: 0.9-1.0, p-value: 0.03) for each additional year. The only factor statistically significant associated with HR-HPV infection was CD4 cell count.

CONCLUSIONS

HR-HPV and abnormal cytology prevalence are high among women in the Amazonas. The low CD4 cell count was an important determinant of HPV infection and abnormal cytological findings. HPV quadrivalent vaccination used in Brazil might not offer protection for an important fraction of HPV-related disease burden in women living with HIV. This is partly explained by the high presence of non targeted vaccine HR-HPVs, such as the HPV genotype groups 56/59/66, 35/39/68 and individually HPV-52 and HPV-45, some of which contribute to high-grade lesion.

A systematic review of factors influencing human papillomavirus vaccination among immigrant parents in the United States

To critically appraise factors influencing human papillomavirus (HPV) vaccination among immigrant parents in the United States, a comprehensive search of electronic databases and reference lists was conducted. The findings from 22 articles were ordered based on a socioecological model. About 30% of children initiated and 14% completed a three-dose series. Correlates of HPV vaccine initiation rates included lack of information, concerns about vaccine safety and promiscuity, providers' recommendations, school mandates, financial issues, immigration laws, and living in disadvantaged neighborhoods. Upstream initiatives embracing cultural descriptors could facilitate HPV vaccination, reducing HPV-related disparities in cancer among immigrants in the US.

Safety profile of the 9-valent human papillomavirus vaccine: assessment in prior quadrivalent HPV vaccine recipients and in men 16 to 26 years of age

A 9-valent HPV (9vHPV) vaccine has been developed to protect against HPV type 6/11/16/18/31/33/45/52/58-related infection and disease. Previous safety analyses from 7 clinical trials conducted in 9vHPV vaccine recipients 9–26 years of age, including comparisons of 9vHPV and quadrivalent HPV (qHPV) vaccines in girls and women 16–26 years of age, showed that the 9vHPV vaccine was generally well tolerated. Additional safety analyses were conducted to include the results of new clinical studies. The safety profile of the 9vHPV vaccine in prior qHPV vaccine recipients (n = 3756 from 1 randomized controlled trial and 2 open-label extension studies) and young men (n = 248 9vHPV and n = 248 qHPV vaccine recipients from 1 randomized controlled trial) was evaluated. Vaccine was administered as a 3-dose regimen (at Day 1 and Months 2 and 6), and adverse events (AEs) were monitored. The most common AEs were injection-site events (91.1% and 79.0% in prior qHPV vaccine recipients and young men, respectively), the majority of which were mild. Discontinuations due to an AE were rare (0.2% and 0.0% among prior qHPV vaccine recipients and young men, respectively). In young men, the AE profile of the 9vHPV vaccine was generally similar to that of the qHPV vaccine. Overall, the 9vHPV vaccine was generally well tolerated in prior qHPV vaccine recipients and in young men, with an AE profile generally consistent with that previously reported with the broader clinical program.

Progress in prophylactic human papillomavirus (HPV) vaccination in 2016: A literature review

Prophylactic human papillomavirus (HPV) vaccine represents a revolutionary step forward in preventing HPV-related cancers, especially cervical carcinoma. Alongside appropriate screening, it has the potential to dramatically reduce cervical cancer incidence and even eradicate it. Following extensive evaluations in clinical trials, the first decade of routine HPV vaccine use provides overwhelming evidence of the vaccines' safety and their real-life effectiveness. In 2016, further clinical trials showed high vaccine efficacy in adult women, especially those that were HPV DNA-negative at baseline, and indicated possible protection from HPV-related diseases after treatment of precancerous cervical lesions. The recommendation for a two-dose schedule in individuals under 15 is further supported for all three licensed vaccines by immunogenicity studies that show non-inferior immune responses and similar clinical efficacy compared to the three-dose schedule. So far, natural competition between HPV types has not been confirmed and therefore vaccine-induced clinically significant type replacement is unlikely. The real-world effectiveness data showed cross-sectional reduction in the prevalence/incidence of vaccine-related HPV types, genital warts and precancerous cervical lesions in countries and regions with HPV vaccination coverage. These declines were evident not only in vaccinated females, but also in unvaccinated females and males, strongly suggesting herd protection. Despite an excellent safety profile consistently demonstrated in clinical trials and confirmed in real-life settings, recently invented controversial syndromes allegedly linked to HPV vaccines temporarily compromised some previously very successful vaccination programs and significantly contributed to the failure of HPV vaccine implementation in some countries with the highest prevalence of cervical cancer. However, several safety studies failed to confirm any association of these syndromes with HPV vaccination in various settings and geographic locations. The main challenges remain implementing HPV vaccination in national vaccination programs, especially in low-and middle-income countries with the highest burden of cervical cancer, and achieving and sustaining high vaccine coverage rates.

Human papillomavirus 9-valent vaccine for cancer prevention: a systematic review of the available evidence

In 2014, the Food and Drug Administration approved a new human papillomavirus 9-valent vaccine (9vHPV), targeting nine HPV types: HPV types 6, 11, 16, and 18, which are also targeted by the quadrivalent HPV vaccine (qHPV), plus five additional high cancer risk HPV types (HPV types 31, 33, 45, 52, and 58). The aim of the current study was to systematically retrieve, qualitatively and quantitatively pool, as well as critically appraise all available evidence on 9vHPV from randomized controlled trials (RCTs). We conducted a systematic review of the literature on 9vHPV efficacy, immunogenicity and safety, as well as a systematic search of registered, completed, and ongoing RCTs. We retrieved and screened 227 records for eligibility. A total of 10 publications reported on RCTs' results on 9vHPV and were included in the review. Sixteen RCTs on 9vHPV have been registered on RCT registries. There is evidence that 9vHPV generated a response to HPV types 6, 11, 16 and 18 that was non-inferior to qHPV. Vaccine efficacy against five additional HPV type-related diseases was directly assessed on females aged 16-26 years (risk reduction against high-grade cervical, vulvar or vaginal disease = 96·7%, 95% CI 80·9%-99·8%). Bridging efficacy was demonstrated for males and females aged 9-15 years and males aged 16-26 years (the lower bound of the 95% CIs of both the geometric mean titer ratio and difference in seroconversion rates meeting the criteria for non-inferiority for all HPV types). Overall, 9vHPV has been proved to be safe and well tolerated. Other RCTs addressed: 9vHPV co-administration with other vaccines, 9vHPV administration in subjects that previously received qHPV and 9vHPV efficacy in regimens containing fewer than three doses. The inclusion of additional HPV types in 9vHPV offers great potential to expand protection against HPV infection. However, the impact of 9vHPV on reducing the global burden of HPV-related disease will greatly depend on vaccine uptake, coverage, availability, and affordability.

Human Papillomavirus and Its Testing Assays, Cervical Cancer Screening, and Vaccination

Human papillomavirus (HPV) was found to be the causative agent for cervical cancer in the 1980s with almost 100% of cervical cancer cases testing positive for HPV. Since then, many studies have been conducted to elucidate the molecular basis of HPV, the mechanisms of carcinogenesis of the virus, and the risk factors for HPV infection. Traditionally, the Papanicolaou test was the primary screening method for cervical cancer. Because of the discovery and evolving understanding of the role of HPV in cervical dysplasia, HPV testing has been recommended as a new method for cervical cancer screening by major professional organizations including the American Cancer Society, American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology. In order to detect HPV infections, many sensitive and specific HPV assays have been developed and used clinically. Different HPV assays with various principles have shown their unique advantages and limitations. In response to a clear causative relationship between high-risk HPV and cervical cancer, HPV vaccines have been developed which utilize virus-like particles to create an antibody response for the prevention of HPV infection. The vaccines have been shown in long-term follow-up studies to be effective for up to 8 years; however, how this may impact screening for vaccinated women remains uncertain. In this chapter, we will review the molecular basis of HPV, its pathogenesis, and the epidemiology of HPV infection and associated cervical cancer, discuss the methods of currently available HPV testing assays as well as recent guidelines for HPV screening, and introduce HPV vaccines as well as their impact on cervical cancer screening and treatments.

Impact and Cost-effectiveness of 3 Doses of 9-Valent Human Papillomavirus (HPV) Vaccine Among US Females Previously Vaccinated With 4-Valent HPV Vaccine

BACKGROUND

We estimated the potential impact and cost-effectiveness of providing 3-doses of nonavalent human papillomavirus (HPV) vaccine (9vHPV) to females aged 13-18 years who had previously completed a series of quadrivalent HPV vaccine (4vHPV), a strategy we refer to as "additional 9vHPV vaccination."

METHODS

We used 2 distinct models: (1) the simplified model, which is among the most basic of the published dynamic HPV models, and (2) the US HPV-ADVISE model, a complex, stochastic, individual-based transmission-dynamic model.

RESULTS

When assuming no 4vHPV cross-protection, the incremental cost per quality-adjusted life-year (QALY) gained by additional 9vHPV vaccination was $146 200 in the simplified model and $108 200 in the US HPV-ADVISE model ($191 800 when assuming 4vHPV cross-protection). In 1-way sensitivity analyses in the scenario of no 4vHPV cross-protection, the simplified model results ranged from $70 300 to $182 000, and the US HPV-ADVISE model results ranged from $97 600 to $118 900.

CONCLUSIONS

The average cost per QALY gained by additional 9vHPV vaccination exceeded $100 000 in both models. However, the results varied considerably in sensitivity and uncertainty analyses. Additional 9vHPV vaccination is likely not as efficient as many other potential HPV vaccination strategies, such as increasing primary 9vHPV vaccine coverage.