Human papillomavirus vaccination: current indications and future directions

Intralesional Quadrivalent Human Papilloma Virus Vaccine Versus Candida Antigen in the Treatment of Multiple Recalcitrant Non-Genital Warts

INTRODUCTION

Warts are the most prevalent clinical manifestation of Human Papilloma Virus (HPV) infections, which vary in morphological pattern depending on the site of the body affected.

OBJECTIVES

To evaluate the safety and efficacy of intralesional quadrivalent HPV vaccine versus candida antigen in treatment of multiple recalcitrant non-genital warts.

METHODS

A randomized-control clinical trial included 60 cases with multiple recalcitrant warts who were randomly distributed into three groups; Group I included 20 patients who received intralesional candida antigen at a dose of 0.3 mL of 1/1000 solution, Group II included 20 patients who received intralesional quadrivalent HPV vaccine at a dose of 0.3ml and Group III included 20 patients who received intralesional injection 0.3 ml of normal saline 0.9% as a control group). Each agent was injected at the base of the largest wart every three weeks until it was completely cleared, or for a total of four sessions.

RESULTS

the highest response rate was detected in the quadrivalent HPV vaccine group (75% complete response) followed by the candida vaccine group (40% complete response and 15% partial response). Also, regarding the distant response rate, the highest response rate was detected in the quadrivalent HPV vaccine group (72.7% complete response and 27.3% partial response) followed by the candida vaccine group (33.3% complete response and 50% partial response).

CONCLUSIONS

Intralesional immunotherapy appears to be effective and safe in treating multiple recalcitrant non-genital warts, with intralesional quadrivalent HPV vaccine outperforming intralesional candida antigen.

Determinants of Low-Income Women's Participation in Self-Collected Samples for Cervical Cancer Detection: Application of the Theory of Planned Behavior

BACKGROUND

Low-income women (LIW) are underrepresented in physician-provided cervical cancer screening. Providing women with an option for Human Papillomavirus (HPV) self-sampling would increase cervical cancer screening. However, little is known about LIW's attitude towards self-sampling for cervical cancer. We determined the associations between the Theory of Planned Behavior (TPB) constructs and LIW intention for participation in the HPV self-sampling.

METHODS

A 44-item survey was administered among women receiving food from a food pantry in central Texas. Independent variables included TPB constructs (i.e., attitudes, subjective norms, and perceived control). The outcome variables were intentions and preference for self-sampling. Both variables were measured on a 5-point scale. Hierarchical linear regression models were used to analyze the data.

RESULTS

A sample of 241 participants (age 50.13 ± 9.60 years) comprising non-Hispanic White (40%), Black/African American (27%), and Hispanic (30%) participated in the study. The participants were current with a pap test (54.8%) and preferred self-sampling (42%). The participant's attitudes and subjective norms were significantly associated with their intention for self-sampling, accounting for 38.7% of the variance (p < .001). Women who were overdue for pap testing versus current with pap testing had increased odds of preferring self-sampling (OR = 1.72, 95% CI: 1.27, 6.04).

CONCLUSIONS

The key predictors for LIW's intention for self-sampling included attitudes and subjective norms. Future research should use the TPB as a framework to examine whether intention predicts self-sampling behavior among LIW.

The Immune Response Generated against HPV Infection in Men and Its Implications in the Diagnosis of Cancer

Human papillomavirus (HPV) infection is associated with precancerous lesions and cancer of the genital tract both in women and men. The high incidence of cervical cancer worldwide focused the research on this infection mainly in women and to a lesser extent in men. In this review, we summarized epidemiological, immunological, and diagnostic data associated with HPV and cancer in men. We presented an overview of the main characteristics of HPV and infection in men that are associated with different types of cancer but also associated with male infertility. Men are considered important vectors of HPV transmission to women; therefore, identifying the sexual and social behavioral risk factors associated with HPV infection in men is critical to understand the etiology of the disease. It is also essential to describe how the immune response develops in men during HPV infection or when vaccinated, since this knowledge could help to control the viral transmission to women, decreasing the incidence of cervical cancer, but also could reduce other HPV-associated cancers among men who have sex with men (MSM). Finally, we summarized the methods used over time to detect and genotype HPV genomes, as well as some diagnostic tests that use cellular and viral biomarkers that were identified in HPV-related cancers.

A Survey on Parents' Health Literacy on Childhood Human Papilloma Virus Vaccination

Objective The aim of this study is to determine parents' knowledge levels and attitudes about childhood human papillomavirus (HPV) vaccination and reveal the differences between parents who are health care workers and nonhealth care workers. The HPV vaccine can potentially prevent initial HPV infection and HPV-related genital and anal precancerous disorders and cancers.

Methods Questions and attitudes toward childhood HPV vaccination were asked to 564 parents who agreed to participate in the study.

Results In our study, the rate of health care worker parents considering having their children vaccinated against HPV (63.1%) was higher than that of nonhealth care worker parents (11.4%). Only 5% of parents had their children previously vaccinated against HPV; however, there was no difference between parents who were health care workers and those who were not. In addition, this rate was relatively low compared to other paid vaccines (49.8, 35.3, and 18.8%, respectively). Parents who had not previously vaccinated their children against HPV were considering getting their children vaccinated, especially if a pediatrician recommended it.

Conclusion The parents' high level of health literacy may not be effective in deciding to vaccinate their children against HPV. Therefore, adequate information and awareness should be provided to all parents about HPV vaccination as early as possible for all children of appropriate age. Pediatricians should be given important roles in raising the awareness of parents about childhood HPV vaccination by health authorities.

The Current and Future States of Screening in Gynecologic Cancers

Gynecologic cancers contribute to a significant portion of cancer morbidity and mortality among women in the United States and across the globe. This article provides a comprehensive review of current screening guidelines and novel techniques that have promise in the prevention and early detection of gynecologic cancers in the future. The authors anticipate a move toward less invasive testing modalities, use of cancer biomarkers, and the prevention and treatment of high-risk factors such as human papilloma virus infection and obesity.

Predictors of the Therapeutic Response to Intralesional Bivalent HPV Vaccine in Wart Immunotherapy

Variable intralesional immunotherapies have recently been proposed as a means of achieving a successful eradication of recurrent and recalcitrant human papillomavirus (HPV)-induced cutaneous and anogenital warts. The bivalent HPV vaccine is one of the newly proposed immunotherapeutic agents. We investigated the role of interleukin-4 (IL-4) and interferon-gamma (IFN-γ) as ex vivo immunologic predictors to estimate the response to the bivalent HPV vaccine as a potential immunotherapy for cutaneous and anogenital warts. Heparinized blood samples were withdrawn from forty patients with multiple recurrent recalcitrant cutaneous and anogenital warts and forty matched healthy control subjects. Whole blood cultures were prepared with and without bivalent HPV vaccine stimulation. Culture supernatants were harvested and stored for IL-4 and IFN-γ measurements using an enzyme-linked immunosorbent assay. A comparative analysis of IL-4 and IFN-γ levels in culture supernatants revealed a non-significant change between the patient and control groups. The bivalent HPV vaccine stimulated cultures exhibited a non-significant reduction in IL-4 levels within both groups. IFN-γ was markedly induced in both groups in response to bivalent HPV vaccine stimulation. The bivalent HPV vaccine can give a sensitive IFN-γ immune response ex vivo, superior to IL-4 and sufficient to predict both the successful eradication of HPV infection and the ultimate clearance of cutaneous and anogenital warts when the bivalent HPV vaccine immunotherapy is applied.

Human papillomavirus (HPV) vaccine status and knowledge of students at a university in rural Thailand

Background

Human papillomavirus (HPV) is a sexually transmitted virus that causes cancers of the cervix, anus, vagina, penis, and oropharynx. HPV vaccination prevents HPV types that commonly cause these cancers. HPV vaccines have been approved in Thailand since 2007. However, the vaccination rate remains low, particularly in young people.

Objectives

This study aimed to investigate the information level regarding HPV infection and vaccination in the younger Thai population, the self-reported vaccination rate, the vaccine intention, and factors affecting the intention.

Methods

This cross-sectional study enrolled a total of 521 undergraduate students (77% female). We used a 34 items self-administered questionnaire (18 questions assessing knowledge level).

Results

The mean score of knowledge was 7.53 ± 4.95 (total score 18), indicating a low-to-moderate level of knowledge. Female gender and health-related majors were significant factors associated with greater knowledge. The self-reported vaccination rate was 1.9% among only female participants. Only 30.3% of the unvaccinated subjects had the intention to receive the vaccine. The factors affecting vaccine intention were female gender and having knowledge score ≥7. The barriers to HPV vaccination were cost (52.2%), and the perception of no need due to low-risk behavior (45.1%).

Conclusion

Education programs on HPV infection and vaccination should be included in the curriculum earlier, if possible, since primary school because the vaccine works best before the onset of sexual activity. In university students, the education programs may encourage the sexually inexperienced students to receive the vaccines, as they are still the ideal group for catch-up vaccination. Moreover, parental education is essential, as national vaccination programs usually target younger people. Knowledge sharing by educated people and organizations could enhance the information level in the communities. Consequently, people become aware of primary prevention by vaccination, which may lead to an increase in vaccination rates and eventually decrease HPV-related cancers.

The effectiveness of vaccination to prevent the papillomavirus infection: a systematic review and meta-analysis

Our purpose was to determine the effectiveness and harms of vaccination in patients with any sexual history to prevent the prevalence of papillomavirus infection. A search strategy was conducted in the MEDLINE, CENTRAL, EMBASE and LILACS databases. Searches were also conducted in other databases and unpublished literature. The risk of bias was evaluated with the Cochrane Collaboration's tool. Analysis of fixed effects was conducted. The primary outcome was the infection by any and each human papillomavirus (HPV) genotype, serious adverse effects and short-term adverse effects. The measure of the effect was the risk difference (RD) with a 95% confidence interval (CI). The planned interventions were bivalent vaccine/tetravalent/nonavalent vs. placebo/no intervention/other vaccines. We included 29 studies described in 35 publications. Bivalent HPV vaccine offers protection against HPV16 (RD −0.05, 95% CI −0.098 to −0.0032), HPV18 (RD −0.03, 95% CI −0.062 to −0.0004) and HPV16/18 genotypes (RD of −0.1, 95% CI −0.16 to −0.04). On the other side, tetravalent HPV vaccine offered protection against HPV6 (RD of −0.0500, 95% CI −0.0963 to −0.0230), HPV11 (RD −0.0198, 95% CI −0.0310 to −0.0085). Also, against HPV16 (RD of −0.0608, 95% CI −0.1126 to −0.0091) and HPV18 (RD of −0.0200, 95% CI −0.0408 to −0.0123). There was a reduction in the prevalence of HPV16, 18 and 16/18 genotypes when applying the bivalent vaccine, with no increase in adverse effects. Regarding the tetravalent vaccine, we found a reduction in the prevalence of HPV6, 11, 16 and 18 genotypes, with no increase in adverse effects.

A Systematic Literature Review of HPV Vaccination Barriers Among Adolescent and Young Adult Males

The human papillomavirus (HPV) causes several cancers and genital warts among sexually active adolescent and young adult (AYA) males. Quadrivalent HPV vaccines were approved for use in the AYA male population in 2010, but vaccination rates have plateaued at around 10%-15%. A better understanding of the barriers AYA male patients, their parents, and their health care providers (HCPs) experience with respect to vaccination uptake is necessary for tailoring interventions for this population. A literature search was conducted through the PubMed and PsycINFO databases in October 2017. Studies were included if they specified at least one barrier to vaccination uptake in AYA males. Studies were excluded if they did not focus on AYA males, their parents, or their HCP; were conducted outside the United States; or were published before 2010. A total of 23 studies were reviewed, and analysis found that these three groups (i.e., AYA males, parents, and HCPs) had significantly different concerns regarding vaccination. The identified themes included the lack of HPV vaccine awareness/information, misinformation about HPV, lack of communication, financial issues relating to uptake, demographic/perceived social norms, and sexual activity. Health care professionals working directly with AYA males and their parents should provide an open route of communication regarding these sensitive issues, and further educate families on the importance of HPV vaccines in reducing the incidence of certain cancers among men in later adulthood.

Knowledge, attitude, and practice on and willingness to pay for human papillomavirus vaccine: a cross-sectional study in Hanoi, Vietnam

BACKGROUND

Despite its effectiveness in preventing human papillomavirus (HPV) infection, the rate of uptake of the HPV vaccine is low in Vietnam. This study aimed to investigate barriers related to knowledge-attitude-practice (KAP) about the HPV vaccine and willingness to pay (WTP) for the vaccine among those using services in an urban vaccination clinic in Hanoi, Vietnam.

MATERIALS AND METHODS

A cross-sectional study was conducted in a vaccination clinic of the Institute for Preventive Medicine and Public Health in Hanoi, Vietnam, from March to April 2016. KAP on the HPV vaccine was collected using a structured questionnaire. Double-bounded dichotomous-choice questions with open-ended questions were used to examine the WTP of respondents. Interval regression and stepwise logistic models were used to identify factors associated with WTP and the average amount that people would be willing to pay for the vaccine.

RESULTS

Of 492 vaccination service users, 67.9%, 94.6%, and 12.3% of respondents were aware of the best age for HPV vaccination, its benefits, and the target group for vaccination, respectively. While the majority believed that the HPV vaccine was safe (92.8%) and effective (90.8%), and desired to be vaccinated (71.1%), only 31.8% of users were vaccinated. Most of the respondents were willing to pay for the HPV vaccine (86.6%), and willing to pay an average amount of US$49.3. Those aged 20-29 years and earning more than 22 million VND/month (very rich) were more likely to pay for the HPV vaccine than people aged <20 years and earning <7 million VND/month. Users who had attained more than a high-school education and heard about the HPV vaccine from doctors, nurses, or other health professionals tended to be willing to pay for the vaccine at a lower price than individuals with below secondary-level education and who had not heard about the vaccine from these health professionals.

CONCLUSION

Sexual health education and financial assistance should be imparted alongside the HPV vaccination program.

The cost of implementing two small media interventions to promote HPV vaccination

OBJECTIVE

To estimate the cost of implementing lay health worker delivered print-based photonovella intervention and iPad-based tailored interactive multimedia intervention (TIMI) to promote Human Papillomavirus (HPV) vaccine uptake and completion among Hispanic parents of daughters 9-17years old.

METHODS

We recruited 301 participants in control, 422 in photonovella, and 239 in TIMI clinics. Intervention costs were estimated using micro-costing from the societal perspective. Cost included time spent planning, training the promotoras, recruiting study participants, and delivering the interventions. Overhead for utilities and project administration was estimated at 30% of direct costs.

RESULTS

The total cost per person for the photonovella and TIMI interventions were $88 and $108, respectively. Less than 10% of costs were fixed and therefore the average cost estimates were insensitive to the size of the target groups.

CONCLUSION

The electronic medium for HPV vaccine education was 23% more costly than the standard low-tech print based approach. The cost difference should be considered relative to the effectiveness of these methods in achieving increases in immunization rates. The cost estimates provide information for cost-effectiveness and budget impact assessments of new HPV immunization intervention programs.

A novel trivalent HPV 16/18/58 vaccine with anti-HPV 16 and 18 neutralizing antibody responses comparable to those induced by the Gardasil quadrivalent vaccine in rhesus macaque model

Persistent infection with human papillomavirus (HPV) is a key factor in the development of precancerous lesions and invasive cervical cancer. Prophylactic vaccines to immunize against HPV are an effective approach to reducing HPV related disease burden. In this study, we investigated the immunogenicity and dosage effect of a trivalent HPV 16/18/58 vaccine (3vHPV) produced in Escherichia coli (E.coli), with Gardasil quadrivalent vaccine (4vHPV, Merck & Co.) as a positive control. Sera collected from rhesus macaques vaccinated with three dosage formulations of 3vHPV (termed low-, mid-, and high-dosage formulations, respectively), and the 4vHPV vaccine were analyzed by both Pseudovirus-Based Neutralization Assay (PBNA) and Enzyme-Linked Immunosorbent Assay (ELISA). Strong immune responses against HPV 16/18/58 were successfully elicited, and dosage-dependence was observed, with likely occurrence of immune interference between different L1-VLP antigens. HPV 16/18 specific neutralizing antibody (nAb) and total immunoglobulin G (IgG) antibody responses in rhesus macaques receiving 3vHPV at the three dosages tested were generally non-inferior to those observed in rhesus macaques receiving 4vHPV throughout the study period. Particularly, HPV 18 nAb titers induced by the mid-dosage formulation that contained the same amounts of HPV 16/18 L1-VLPs as Gardasil 4vHPV were between 7.3 to 12.7-fold higher compared to the positive control arm from weeks 24-64. The durability of antibody responses specific to HPV 16/18 elicited by 3vHPV vaccines was also shown to be non-inferior to that associated with Gardasil 4vHPV.

VIA/VILI is more suitable for cervical cancer prevention in Chinese poverty-stricken region: a health economic evaluation

Background

Screening is the main preventive method for cervical cancer in developing countries, but each type of screening has advantages and disadvantages. To investigate the most suitable method for low-income areas in China, we conducted a health economic analysis comparing three methods: visual inspection with acetic acid and Lugol’s iodine (VIA/VILI), ThinPrep cytology test (TCT), and human papillomavirus (HPV) test.

Methods

We recruited 3086 women aged 35–65 years using cluster random sampling. Each participant was randomly assigned to one of three cervical cancer screening groups: VIA/VILI, TCT, or HPV test. In order to calculate the number of disability-adjusted life years (DALYs) averted by each screening method, we used Markov models to estimate the natural development of cervical cancer over a 15-year period to estimate the age of onset and duration of each disease stage. The cost-effectiveness ratios (CERs), net present values (NPVs), benefit-cost ratios (BCRs), and cost-utility ratios (CURs) were used as outcomes in the health economic analysis.

Results

The positive detection rate in the VIA/VILI group was 1.39%, which was 4.6 and 2.0 times higher than the rates in the TCT and HPV test groups, respectively. The positive predictive value of VIA/VILI (10.53%) was highest while the rate of referral for colposcopy was lowest for those in the HPV + TCT group (0.60%). VIA/VILI performed the best in terms of health economic evaluation results, as the cost of per positive case detected was 8467.9 RMB, which was 24503.0 RMB lower than that for TCT and 5755.9 RMB lower than that for the HPV test. In addition, the NPV and BCR values were 258011.5 RMB and 3.18 (the highest), and the CUR was 2341.8 RMB (the lowest). The TCT performed the worst, since its NPV was <0 and the BCR was <1, indicative of being poorly cost-beneficial.

Conclusions

With the best economic evaluation results and requiring minimum medical resources, VIA/VILI is recommended for cervical cancer screening in poverty-stricken areas in China with high incidence of cervical cancer and lack of medical resources.

Human papillomavirus and gastrointestinal cancer: A review

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide. Exposure to HPV is very common, and an estimated 65%-100% of sexually active adults are exposed to HPV in their lifetime. The majority of HPV infections are asymptomatic, but there is a 10% chance that individuals will develop a persistent infection and have an increased risk of developing a carcinoma. The International Agency for Research on Cancer has found that the following cancer sites have a strong causal relationship with HPV: cervix uteri, penis, vulva, vagina, anus and oropharynx, including the base of the tongue and the tonsils. However, studies of the aetiological role of HPV in colorectal and esophageal malignancies have conflicting results. The aim of this review was to organize recent evidence and issues about the association between HPV infection and gastrointestinal tumours with a focus on esophageal, colorectal and anal cancers. The ultimate goal was to highlight possible implications for prognosis and prevention.

High Burden of Human Papillomavirus (HPV) Infection among Young Women in KwaZulu-Natal, South Africa

OBJECTIVES

HPV infection causes cervical cancer, yet information on prevalence and risk factors for HPV in Africa remain sparse. This study describes the prevalence of HPV genotypes and risk factors associated with HPV among young women ≤ 30 years of age in KwaZulu-Natal (KZN), South Africa.

METHODS

Cervicovaginal lavage samples were tested for HPV genotypes in 224 women enrolled in a prospective cohort study. Clinical, behavioural and demographic data were collected. We measured prevalence of HPV genotypes and using logistic regression, examined for factors associated with HPV.

RESULTS

Median age of participants was 21 years [interquartile range (IQR):18-23]. The overall prevalence of HPV was 76.3% (171/224) with multiple and single genotypes prevalent in 56.3% and 20.1% of women respectively. Proportion of women with high-risk genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56 and 58) was 54.5%. Women not living with their partner [adjusted odds ratio (aOR)] = 3.42 95% CI1.22-9.60; p = 0.019), was significantly associated with HPV infection and high-risk HPV genotype infection.

CONCLUSION

The high burden of HPV and associated risk behaviours highlight the need to intensify behavioural interventions to prevent HPV acquisition in young women. The large scale delivery of HPV vaccine should be prioritised to prevent HPV acquisition and reduce HPV-related morbidity.

The estimated lifetime probability of acquiring human papillomavirus in the United States

BACKGROUND

Estimates of the lifetime probability of acquiring human papillomavirus (HPV) can help to quantify HPV incidence, illustrate how common HPV infection is, and highlight the importance of HPV vaccination.

METHODS

We developed a simple model, based primarily on the distribution of lifetime numbers of sex partners across the population and the per-partnership probability of acquiring HPV, to estimate the lifetime probability of acquiring HPV in the United States in the time frame before HPV vaccine availability.

RESULTS

We estimated the average lifetime probability of acquiring HPV among those with at least 1 opposite sex partner to be 84.6% (range, 53.6%-95.0%) for women and 91.3% (range, 69.5%-97.7%) for men. Under base case assumptions, more than 80% of women and men acquire HPV by age 45 years.

CONCLUSIONS

Our results are consistent with estimates in the existing literature suggesting a high lifetime probability of HPV acquisition and are supported by cohort studies showing high cumulative HPV incidence over a relatively short period, such as 3 to 5 years.

HPV and Cervical Dysplasia in Adolescents: A Progressive March Toward Prevention

Cervical cancer caused by infection with the human papillomavirus is the second most common malignancy among women worldwide. Over the course of the past century our understanding of the virus and the disease has expanded exponentially through landmark studies and pioneers of academic medicine. It has all led to the current evidence-based guidelines for prevention of cervical dysplasia and invasive carcinoma in adolescent females that will significantly lessen morbidity and mortality and may eradicate the disease completely. Unfortunately, the greatest challenge to this may be overcoming common misunderstandings and other barriers to compliance with these guidelines among practitioners, patients, and the general public.