Gardasil-9: A global survey of projected efficacy

Candidate HPV genotypes not included in the 9-valent vaccine for prevention of CIN 2-3

OBJECTIVES

To identify the prevalence of human papillomavirus genotypes - as a single infection or co-infection - not included in the 9-valent (9v) HPV vaccine among women with cervical intraepithelial neoplasia (CIN 2-3).

METHODS

Retrospective study of 1700 women referred due to abnormal cytology to Sant Joan de Deu Hospital. We selected 849 patients with CIN 2 or CIN 3 diagnosis confirmed by biopsy. An HPV test, a second cytology, and colposcopy were performed on all patients.Those with abnormal colposcopy underwent cervical biopsy. Patients with abnormal cytology and normal colposcopy or transformation zone type 3 underwent endocervical curetage. Conization was performed if punch biopsy or endocervical curetage confirmed CIN 2-3 or if a CIN 1 lesion persisted (diagnosed by biopsy) over 2 years in patients over 25 years of age. Comparisons for qualitative variables were analyzed with the chi-squared test. Analysis of variance was used for comparisons involving more than two samples.

RESULTS

HPV was detected in 746 of 849 patients (87.9%) and in 306 (41%) of those where more than one HPV genotype was present. The more frequent genotypes detected as single infection were: HPV-16 (267/849%-31.4%), HPV 31 (34/849-4%), HPV-33 (20/849%-2.4%), HPV-58 (17/849%-2%), HPV-51 (15/849%-1.8%), and HPV-53 (12/849%-1.4%). The more frequent genotypes isolated including multiple HPV infection were HPV-16 (427/849%-50.2%), HPV-31 (108/849%-12.7%), HPV-51 (79/849%-9.3%), HPV-33 (67/849%-7.8%), HPV-58 (67/849%-7.8%), and HPV-52 (59/849%-6.9%). In total, 78% of women diagnosed with CIN 2 or CIN 3 had an infection by a HPV genotype included in the 9v vaccine. Of the 849 women diagnosed with CIN 2 or CIN 3, 103 (12.1%) tested negative for HPV and 106 (12.4%) tested positive for low-risk HPV types.

CONCLUSIONS

Inclusion of HPV-51, 53, 66, and 35 in a new vaccine may not be advisable as most are detected as coinfection with other high-risk genotypes that are already included in the current vaccines.

Cervical cancer screening coverage, management of squamous intraepithelial lesions and related costs in France

Until 2018, cervical cancer screening in France was an unorganized individual screening, with the exception of some pilot programs in some territories. We aimed to assess, before the implementation of organized cervical cancer screening and human papillomavirus (HPV) nonavalent vaccine introduction in the vaccination schedule in 2018, (i) the individual cervical cancer screening coverage, (ii) the management of squamous intraepithelial lesions (SIL) and (iii) the related costs. We used the Système National des Données de Santé (SNDS) (Echantillon Généraliste de Bénéficiaires [EGB] and Programme de Médicalisation des systèmes d'information [PMSI]) to assess the cervical screening coverage rate in France between January 1st, 2012 and December 31st, 2014, and to describe diagnostic investigations and therapeutic management of SIL in 2013. After extrapolation to the general population, a total of 10,847,814 women underwent at least one smear test over the 3-year study period, corresponding to a coverage rate of 52.4% of the women aged 25 to 64 included. In 2013, 126,095 women underwent HPV test, 327,444 women underwent colposcopy, and 9,653 underwent endocervical curettage; 31,863 had conization and 12,162 had laser ablation. Besides, 34,067 women experienced hospital stays related to management of SIL; 25,368 (74.5%) had high-grade lesions (HSIL) and 7,388 (21.7%) low-grade lesions (LSIL). Conization was the most frequent in-hospital therapeutic procedure: 89.5% (22,704) of women with an in-hospital procedure for HSIL and 64.7% (4,781) for LSIL. Mean cost of smear test, colposcopy and HPV tests were around 50€. Total cost for hospital stays in 2013 was estimated at M41€, or a mean cost of 1,211€ per woman; 76% were due to stays with HSIL. This study highlights the low coverage rate of individual cervical cancer screening and a high burden related to SIL management.

Virus-like Particle-Based L2 Vaccines against HPVs: Where Are We Today?

Human papillomaviruses (HPVs) are the most common sexually transmitted infections worldwide. Ninety percent of infected individuals clear the infection within two years; however, in the remaining 10% of infected individuals, the infection(s) persists and ultimately leads to cancers (anogenital cancers and head and neck cancers) and genital warts. Fortunately, three prophylactic vaccines have been approved to protect against HPV infections. The most recent HPV vaccine, Gardasil-9 (a nonavalent vaccine), protects against seven HPV types associated with ~90% of cervical cancer and against two HPV types associated with ~90% genital warts with little cross-protection against non-vaccine HPV types. The current vaccines are based on virus-like particles (VLPs) derived from the major capsid protein, L1. The L1 protein is not conserved among HPV types. The minor capsid protein, L2, on the other hand, is highly conserved among HPV types and has been an alternative target antigen, for over two decades, to develop a broadly protective HPV vaccine. The L2 protein, unlike the L1, cannot form VLPs and as such, it is less immunogenic. This review summarizes current studies aimed at developing HPV L2 vaccines by multivalently displaying L2 peptides on VLPs derived from bacteriophages and eukaryotic viruses. Recent data show that a monovalent HPV L1 VLP as well as bivalent MS2 VLPs displaying HPV L2 peptides (representing amino acids 17–36 and/or consensus amino acids 69–86) elicit robust broadly protective antibodies against diverse HPV types (6/11/16/18/26/31/33/34/35/39/43/44/45/51/52/53/56/58/59/66/68/73) associated with cancers and genital warts. Thus, VLP-based L2 vaccines look promising and may be favorable, in the near future, over current L1-based HPV vaccines and should be explored further.

Systematic review and meta-analysis of human papillomavirus prevalence and types among women with normal cervical cytology in the Eastern Mediterranean Region

Aim: To predict the impact of human papillomavirus (HPV) vaccines in the Eastern Mediterranean Region (EMRO), knowing the prevalence and type distribution of HPV are mandatory. Methods: This study investigated 26,536 women with normal cervical cytology based on the data available from 13 countries of EMRO. Results: The HPV prevalence estimated to be 9.3% (CI = 7.1–12.0). The five most frequent HPV types were HPV 16 (2.3%), 18 (0.7%), 6 (0.7%), 11 (0.6%) and 31 (0.5%). The prevalence of multiple infections of HPV was observed in 1.6% of all cases. Conclusion: The present meta-analysis provides a comprehensive summary of HPV type distribution in normal cervical cytology in EMRO region to estimate and predict the impact of HPV vaccines.

A Current Update on Human Papillomavirus-Associated Head and Neck Cancers

Human papillomavirus (HPV) infection is the cause of a growing percentage of head and neck cancers (HNC); primarily, a subset of oral squamous cell carcinoma, oropharyngeal squamous cell carcinoma, and laryngeal squamous cell carcinoma. The majority of HPV-associated head and neck cancers (HPV + HNC) are caused by HPV16; additionally, co-factors such as smoking and immunosuppression contribute to the progression of HPV + HNC by interfering with tumor suppressor miRNA and impairing mediators of the immune system. This review summarizes current studies on HPV + HNC, ranging from potential modes of oral transmission of HPV (sexual, self-inoculation, vertical and horizontal transmissions), discrepancy in the distribution of HPV + HNC between anatomical sites in the head and neck region, and to studies showing that HPV vaccines have the potential to protect against oral HPV infection (especially against the HPV types included in the vaccines). The review concludes with a discussion of major challenges in the field and prospects for the future: challenges in diagnosing HPV + HNC at early stages of the disease, measures to reduce discrepancy in the prevalence of HPV + HNC cases between anatomical sites, and suggestions to assess whether fomites/breast milk can transmit HPV to the oral cavity.

The impact of 10 years of human papillomavirus (HPV) vaccination in Australia: what additional disease burden will a nonavalent vaccine prevent?

Background: A National human papilloma virus (HPV) Vaccination Programme for the prevention of HPV infection and associated disease using the quadrivalent HPV vaccine (4vHPV) has been funded and implemented in Australia since 2007, initially for girls only and extended to boys in 2013, with uptake rates among the highest observed worldwide. Aim: We report on the impact of this national programme on HPV prevalence and associated disease burden and estimate the potential impact of adopting a nonavalent HPV (9vHPV) vaccine. Methods: We performed a non-systematic literature review of studies measuring the burden of HPV-associated disease and infection in Australia before and after introduction of HPV vaccination. We also included key national reports with estimates of HPV-related disease burden. Results: Substantial declines in high-grade cervical disease and genital warts among vaccine-eligible women have been observed. Reductions in genital warts incidence and HPV prevalence among heterosexual men of similar age were observed before introduction of the male vaccination programme, indicating a substantial herd effect. 9vHPV vaccine is expected to prevent up to 90% of cervical and 96% of anal cancers. Of an estimated 1,544 HPV-associated cancers in 2012, 1,242 would have been preventable by the 4vHPV vaccine and an additional 187 anogenital cancers by the 9vHPV vaccine. Conclusions: Vaccination using 4vHPV vaccine has had a large demonstrable impact on HPV-related disease in Australia. A switch to 9vHPV could further reduce the HPV-associated cancer burden. With continued high coverage among both males and females, elimination of vaccine-type HPV disease seems achievable in Australia.

A Meta-Analysis on Human Papillomavirus Type Distribution among Women with Cervical Neoplasia in the WHO Eastern Mediterranean Region

INTRODUCTION

To date, the human papillomavirus (HPV) vaccine has not been integrated into the national vaccination program of most countries of the WHO Eastern Mediterranean Region (EMRO), except for the United Arab Emirates and Libya. The knowledge of HPV genotype distribution in cervical neoplasia is valuable to predict the impact of current HPV vaccines on cancer prevention and can help the health policymakers to select the most appropriate vaccine types in their countries.

METHODS

Hence, this meta-analysis recapitulates all available data on HPV prevalence and genotypes in women with atypical squamous cells of undetermined significance (ASCUS), cervical intraepithelial neoplasia (CIN) I-III or low- and high-grade squamous intraepithelial lesions (LSIL and HSIL, respectively), and invasive cervical cancer (ICC) in EMRO countries.

RESULTS

The meta-analysis included 5,990 cases of cervical precancer and cancer. The overall HPV prevalence was 85.4, 71.3, 59.2, and 34.8% in women with ICC, CIN II-III or HSIL, CIN I or LSIL, and ASCUS, respectively. HPV 16 was the most common genotype followed by HPV 18, representing 58 and 16.5% in ICC cases, respectively.

CONCLUSION

This meta-analysis showed that the introduction of current HPV vaccines into national vaccination programs and the establishment of comprehensive screening programs in EMRO countries is beneficial by preventing 74.5% of cervical neoplasia.

Cervical intraepithelial neoplasia grade 3 in a patient following Gardasil vaccination

Essentially all cervical dysplasia is caused by human papilloma virus (HPV). Three HPV vaccines have been available, with Gardasil-9 being the most recently approved in the USA. Gardasil-9 covers high-risk HPV strains 16, 18, 31, 33, 45, 52 and 58 as well as low-risk strains 6 and 11. A 33-year-old woman (Gravida 2, Para 2) received Gardasil in 2006. Subsequently, her pap smear revealed low grade squamous intraepithelial lesion. Cervical biopsies performed in 2015 and 2016 revealed cervical intraepithelial neoplasia grade 1 (CIN 1). She underwent loop electrosurgical excision procedure for persistent CIN 1, which demonstrated CIN 3. Genotyping revealed HPV type 56 infection. The advancement of Gardasil-9 vaccine only offers 90% protection to patients against HPV-related disease. Lay literature may mislead patients to think they have no risk of HPV infection.

Immune response and reactogenicity of an unadjuvanted intradermally delivered human papillomavirus vaccine using a first generation Nanopatch™ in rhesus macaques: An exploratory, pre-clinical feasibility assessment

The human papillomavirus (HPV) 9-valent, recombinant vaccine (Gardasil™9) helps protect young adults (males and females) against anogenital cancers and genital warts caused by certain HPV genotypes (ref. Gardasil™9 insert). This vaccine is administered intramuscularly (IM). The aim of this study was to determine preclinically whether intradermal (ID) vaccination with an unadjuvanted 9-valent recombinant HPV vaccine using a first-generation ID delivery device, the Nanopatch™, could enhance vaccine immunogenicity compared with the traditional ID route (Mantoux technique). IM injection of HPV VLPs formulated with Merck & Co., Inc., Kenilworth, NJ, USA Alum Adjuvant (MAA) were included in the rhesus study for comparison. The Nanopatch™ prototype contains a high-density array comprised of 10,000 microprojections/cm², each 250 µm long. It was hypothesized the higher density array with shallower ID delivery may be superior to the Mantoux technique. To test this hypothesis, HPV VLPs without adjuvant were coated on the Nanopatch™, stability of the Nanopatch™ with unadjuvanted HPV VLPs were evaluated under accelerated conditions, skin delivery was verified using radiolabelled VLPs or FluoSpheres®, and the immune response and skin site reaction with the Nanopatch™ was evaluated in rhesus macaques. The immune response induced by Nanopatch™ administration, measured as HPV-specific binding antibodies, was similar to that induced using the Mantoux technique. It was also observed that a lower dose of unadjuvanted HPV VLPs delivered with the first-generation Nanopatch™ and applicator or Mantoux technique resulted in an immune response that was significantly lower compared to a higher-dose of alum adjuvanted HPV VLPs delivered IM in rhesus macaques. The study also indicated unadjuvanted HPV VLPs could be delivered with the first-generation Nanopatch™ and applicator to the skin in 15 s with a transfer efficiency of approximately 20%. This study is the first demonstration of patch administration in non-human primates with a vaccine composed of HPV VLPs.

High prevalence of cervical high-risk human papillomavirus infection mostly covered by Gardasil-9 prophylactic vaccine in adult women living in N'Djamena, Chad

Background

We conducted in 2018 a descriptive, quantitative, population-based, cross-sectional survey estimating the prevalence of cervical high-risk human papillomavirus (HR-HPV) infection and associated risk factors among adult women living in N’Djamena, Chad.

Methods

Five of the 10 districts of N’Djamena were randomly selected for inclusion. Peer educators contacted adult women in community-churches or women association networks to participate in the survey and come to the clinic for women’s sexual health “La Renaissance Plus”, N’Djamena. Medical, socio-demographical and behavioral informations were collected. HPV DNA was detected and genotyped in endocervical swab using Anyplex II HPV28 genotyping test (Seegene, Seoul, South Korea).

Results

253 women (mean age, 35.0 years; range, 25–65) including 3.5% of HIV-positive women were prospectively enrolled. The prevalence of HPV infection was 22.9%, including 68.9% of HR-HPV infection and 27.6% being infected with multiple genotypes, providing a total HR-HPV prevalence of 15.8% (95% CI%: 11.3–20.3). The most prevalent HR-HPV genotypes were HPV-58, HPV-35, HPV-56, HPV-31, HPV-16, HPV-45, HPV-52 and HPV-18. HPV types targeted by the prophylactic Gardasil-9 vaccine were detected in nearly 70% (67.5%) and HPV-58 was the most frequently detected. HIV infection was a risk factor strongly associated with cervical infection with any HPV [adjusted Odds ratio (aOR): 17.4], multiple types of HPV (aOR: 8.9), HR-HPV (aOR: 13.2) and cervical infection with multiple HR-HPV (aOR: 8.4).

Conclusion

These observations highlight the unsuspected high burden of cervical HR-HPV infection in Chadian women, and point the potential risk of further development of HPV-associated cervical precancerous and neoplastic lesions in a large proportion of women in Chad. The high rate of preventable Gardasil-9 vaccine genotypes constitutes the rationale for introducing primary vaccine prevention against cervical cancer in young female adolescents living in Chad.

Human papillomavirus in Ethiopia

Over 99% of cervical cancer cases are associated with genital infection by certain types of human papillomaviruses (HPVs). To outline optimal vaccination strategies and HPV based cervical cancer screening, synthesized data on the genotype distribution of HPV is fundamental that is otherwise missed in Ethiopia. The aim of this study is to compile the findings on HPV genotyping in Ethiopia. Published articles were systematically searched using comprehensive search strings from PubMed/Medline and SCOPUS. Further, Google Scholar and the Google databases were also searched manually for grey literature. The included studies in the review employed 859 women (age range 15-85 years) with different kinds of cervical abnormalities. A total of 534 HPV sequences were reported; the proportion of high risk HPVs was varied 80.4-100%. The top five identified genotypes were HPV 16 (45.3%; 95% CI 41.1-49.6%), HPV 52 (9.4%; 95% CI 7.2-12.1%), HPV 18 (8.2%; 95% CI 6.2-10.9%), HPV 58 (6.9%; 95% CI 5.1-9.4%) and HPV 45 (5.2%; 95% CI 3.7-7.5%). The combined prevalence of HPV 16/18 was at 53.6% (95% CI 49.3-57.8%). In this review, HPV 16 in particular, but also HPV 52 and 18, warrant exceptional consideration in vaccination and HPV based screening programs in Ethiopia. To the best of our knowledge, this study represents the first of its kind to establish the genotype distribution of HPV from different kinds of cervical lesions in Ethiopia although it was synthesized out of few studies. Hence, additional nationwide data are needed to strengthen our finding.

Natural history of human papillomavirus and vaccinations in men: A literature review

BACKGROUND AND AIMS

Infection with high-risk (HR) genotypes of the human papillomavirus (HPV) is necessary for and causative of almost all cervical cancers and their precursor condition, cervical intraepithelial neoplasia. These conditions have been sharply reduced by cervical cytology screening, and a further decrease is expected because of the recent introduction of prophylactic HPV vaccinations. While significant attention has been given to gynecologic HPV disease, men can be affected by HPV-related cancers of the anus, penis, and oropharynx. This literature review aims to address disparities in HPV-related disease in men, and certain HR male subpopulations, compared with women.

DISCUSSION

Overall, immunocompetent men are far less likely than women to develop anogenital HPV-related cancers, despite harboring HR HPV infections at anogenital sites. On the other hand, men who have sex with men and men living with human immunodeficiency virus infection are at considerably higher risk of HPV-related disease. Historic rates of prophylactic HPV vaccination in males have trailed those of females due to numerous multilevel factors, although, in recent years, this sex gap in vaccination coverage has been closing. In the absence of routine HPV screening in males, therapeutic vaccinations have emerged as a potential treatment modality for preinvasive neoplasia and are in various phases of clinical testing.

CONCLUSION

Successful reductions in HPV disease morbidity at the population level must acknowledge and target HPV infections in men.

Evaluation of the thermal stability and the protective efficacy of spray-dried HPV vaccine, Gardasil® 9

High-risk human papillomavirus (HPV) types are responsible for nearly all cases of cervical cancers. Cervarix® and Gardasil® 9 are the current prophylactic vaccines available that protect against the majority of HPVs associated with cancer. Although these vaccines are highly effective, HPV vaccine implementation has been slow, particularly in low-and-middle income countries. Major barriers to the widespread availability of the HPV vaccines is its cost and the requirement for continuous refrigeration (2-8°C). Here, we used spray drying along with stabilizing excipients to formulate a thermostable Gardasil® 9 vaccine. We evaluated the immunogenicity and protective efficacy of the vaccine in mice immediately after spray drying and following storage for three months at 4°C, 25°C, and 40°C. The immunogenicity studies were performed using Gardasil® 9 as a whole antigen, and not individual HPV types, for ELISA. At the dose tested, the spray dried vaccine conferred protection against HPV following storage at temperatures up to 40°C. In addition to the spray-dried vaccine, our studies revealed that the Gardasil® 9 vaccine, as currently marketed, may be stored and transported at elevated temperatures for up to 3 months without losing efficacy, especially against HPV16. This study is critical, as a thermostable vaccine will decrease vaccine cost associated with cold-chain maintenance and could increase vaccine access and coverage, especially in remote regions of the world.

Pathways to a cancer-free future: A protocol for modelled evaluations to maximize the future impact of interventions on cervical cancer in Australia

OBJECTIVE

Australia's HPV vaccination and HPV-based cervical screening programs are changing the landscape in cervical cancer prevention. We aim to identify areas which can make the biggest further impact on cervical cancer burden. This protocol describes the first stage of a program of work called Pathways-Cervix that aims to generate evidence from modelled evaluations of interventions across the cervical cancer spectrum.

METHODS

Based on evidence from literature reviews and guidance from a multi-disciplinary Scientific Advisory Committee (SAC), the most relevant evaluations for prevention, diagnosis and treatment were identified.

RESULTS

Priority evaluations agreed by the SAC included: increasing/decreasing and retaining vaccination uptake at the current level; vaccinating older women; increasing screening participation; methods for triaging HPV-positive women; improving the diagnosis of cervical intraepithelial neoplasia (CIN) and cancer; treating cervical abnormalities and cancer; and vaccinating women treated for CIN2/3 to prevent recurrence. Evaluations will be performed using a simulation model, Policy1-Cervix previously used to perform policy evaluations in Australia. Exploratory modelling of interventions using idealised scenarios will initially be conducted in single birth cohorts. If these have a significant impact on findings then evaluations with more realistic assumptions will be conducted. Promising strategies will be investigated further by multi-cohort simulations predicting health outcomes, resource use and cost outcomes.

CONCLUSIONS

Pathways-Cervix will assess the relative benefits of strategies and treatment options in a systematic and health economic framework, producing a list of 'best buys' for future decision-making in cervical cancer control.

Oral immunization with bacteriophage MS2-L2 VLPs protects against oral and genital infection with multiple HPV types associated with head & neck cancers and cervical cancer

Human papillomaviruses (HPVs) are the most common sexually transmitted infections. HPVs are transmitted through anogenital sex or oral sex. Anogenital transmission/infection is associated with anogenital cancers and genital warts while oral transmission/infection is associated with head and neck cancers (HNCs) including recurrent respiratory papillomatosis. Current HPV vaccines protect against HPV types associated with ∼90% of cervical cancers and are expected to protect against a percentage of HNCs. However, only a few studies have assessed the efficacy of current vaccines against oral HPV infections. We had previously developed a mixed MS2-L2 candidate HPV vaccine based on bacteriophage MS2 virus-like particles (VLPs). The mixed MS2-L2 VLPs consisted of a mixture of two MS2-L2 VLPs displaying: i) a concatemer of L2 peptide (epitope 20-31) from HPV31 & L2 peptide (epitope 17-31) from HPV16 and ii) a consensus L2 peptide representing epitope 69-86. The mixed MS2-L2 VLPs neutralized/protected mice against six HPV types associated with ∼87% of cervical cancer. Here, we show that the mixed MS2-L2 VLPs can protect mice against additional HPV types; at the genital region, the VLPs protect against HPV53, 56, 11 and at the oral region, the VLPs protect against HPV16, 35, 39, 52, and 58. Thus, mixed MS2-L2 VLPs protect against eleven oncogenic HPV types associated with ∼95% of cervical cancer. The VLPs also have the potential to protect, orally, against the same oncogenic HPVs, associated with ∼99% of HNCs, including HPV11, which is associated with up to 32% of recurrent respiratory papillomatosis. Moreover, mixed MS2-L2 VLPs are thermostable at room temperature for up to 60 days after spray-freeze drying and they are protective against oral HPV infection.

Induction of neutralizing antibodies by human papillomavirus vaccine generated in mammalian cells

Background

Cervical cancer caused by human papillomavirus (HPV) infections is one of the most common cancers affecting women worldwide. Current preventative HPV vaccines on the market are composed of HPV L1 protein produced either in the yeast such as Gardasil or in the insect cells such as Cervarix. The duration of efficacy and cross-protection remain highly desirable for the improvement of current prophylactic HPV vaccine. Given that HPV carries out infection and replicates in mammalian cells, L2 protein, which is not included in the current licensed vaccines, is included in the third generation of HPV vaccine in pursuing of providing broader prevention. We hypothesize that a virus-like particle (VLP) consisting of HPV L1 plus L2 proteins generated in mammalian cells will present conformations more closely to native HPV, thus it will provide more durable and broader efficacy of prevention.

Methods

We took advantage of 293TT cells to produce VLP containing L1 and L2 proteins of HPV16 and HPV18, respectively.

Results

VLP particles of uniformed size and morphology were observed, and potent and broadly neutralizing antibodies were induced in mice and rabbits. In addition, compared to bivalent HPV vaccine of Cervarix, our HPV L1-L2 VLPs elicited higher titer of anti-sera, and the anti-sera also presented comparable neutralization potency against HPV16 and HPV18 infections even a much less potent adjuvant was used in our case.

Conclusion

Our VLPs were capable of eliciting stronger and more broadly neutralizing activities against various HPV subtypes and were potential candidate HPV vaccines.

Persuasive messaging for human papillomavirus vaccination by adolescent providers in a five-country multi-site study

OBJECTIVE

Strong persuasive messaging by providers is a key predictor for patient acceptance of prophylactic human papillomavirus vaccination. We aimed to determine optimal messaging to promote human papillomavirus adolescent vaccination across different geographical sites.

METHODS

Adolescent providers (n = 151) from Argentina, Malaysia, South Africa, South Korea, and Spain were surveyed on messages, family decision makers, and sources of communication to best motivate parents to vaccinate their adolescent daughters overall, and against human papillomavirus. Multivariate logistic regression assessed the likelihood of recommending messages specifically targeted at cervical cancer with providers' characteristics: gender, medical specialization, and previous administration of human papillomavirus vaccination.

RESULTS

Mothers were considered the most important human papillomavirus vaccination decision makers for their daughters (range 93%-100%). Television was cited as the best source of information on human papillomavirus vaccination in surveyed countries (range 56.5%-87.1%), except Spain where one-on-one discussions were most common (73.3%). Prevention messages were considered the most likely to motivate parents to vaccinate their daughters overall, and against human papillomavirus, in all five countries (range 30.8%-55.9%). Optimal messages emphasized cervical cancer prevention, and included strong provider recommendation to vaccinate, vaccine safety and efficacy, timely vaccination, and national policy for human papillomavirus vaccination. Pediatricians and obstetricians/gynecologists were more likely to cite that the best prevention messages should focus on cervical cancer (OR: 4.2, 95% CI: 1.17 to 15.02 vs other medical specialists).

CONCLUSIONS

Provider communication messages that would motivate parents to vaccinate against human papillomavirus were based on strong recommendation emphasizing prevention of cervical cancer. To frame convincing messages to increase vaccination uptake, adolescent providers should receive updated training on human papillomavirus and associated cancers, while clearly addressing human papillomavirus vaccination safety and efficacy.

Advances in Designing and Developing Vaccines, Drugs and Therapeutic Approaches to Counter Human Papilloma Virus

Human papillomavirus (HPV) is a viral infection with skin-to-skin based transmission mode. HPV annually caused over 500,000 cancer cases including cervical, anogenital and oropharyngeal cancer among others. HPV vaccination has become a public-health concern, worldwide, to prevent the cases of HPV infections including precancerous lesions, cervical cancers, and genital warts especially in adolescent female and male population by launching national programs with international alliances. Currently, available prophylactic and therapeutic vaccines are expensive to be used in developing countries for vaccination programs. The recent progress in immunotherapy, biotechnology, recombinant DNA technology and molecular biology along with alternative and complementary medicinal systems have paved novel ways and valuable opportunities to design and develop effective prophylactic and therapeutic vaccines, drugs and treatment approach to counter HPV effectively. Exploration and more researches on such advances could result in the gradual reduction in the incidences of HPV cases across the world. The present review presents a current global scenario and futuristic prospects of the advanced prophylactic and therapeutic approaches against HPV along with recent patents coverage of the progress and advances in drugs, vaccines and therapeutic regimens to effectively combat HPV infections and its cancerous conditions.

The precision prevention and therapy of HPV-related cervical cancer: new concepts and clinical implications

Cervical cancer is the third most common cancer in women worldwide, with concepts and knowledge about its prevention and treatment evolving rapidly. Human papillomavirus (HPV) has been identified as a major factor that leads to cervical cancer, although HPV infection alone cannot cause the disease. In fact, HPV-driven cancer is a small probability event because most infections are transient and could be cleared spontaneously by host immune system. With persistent HPV infection, decades are required for progression to cervical cancer. Therefore, this long time window provides golden opportunity for clinical intervention, and the fundament here is to elucidate the carcinogenic pattern and applicable targets during HPV-host interaction. In this review, we discuss the key factors that contribute to the persistence of HPV and cervical carcinogenesis, emerging new concepts and technologies for cancer interventions, and more urgently, how these concepts and technologies might lead to clinical precision medicine which could provide prediction, prevention, and early treatment for patients.

Trial watch: Peptide-based vaccines in anticancer therapy

Peptide-based anticancer vaccination aims at stimulating an immune response against one or multiple tumor-associated antigens (TAAs) following immunization with purified, recombinant or synthetically engineered epitopes. Despite high expectations, the peptide-based vaccines that have been explored in the clinic so far had limited therapeutic activity, largely due to cancer cell-intrinsic alterations that minimize antigenicity and/or changes in the tumor microenvironment that foster immunosuppression. Several strategies have been developed to overcome such limitations, including the use of immunostimulatory adjuvants, the co-treatment with cytotoxic anticancer therapies that enable the coordinated release of damage-associated molecular patterns, and the concomitant blockade of immune checkpoints. Personalized peptide-based vaccines are also being explored for therapeutic activity in the clinic. Here, we review recent preclinical and clinical progress in the use of peptide-based vaccines as anticancer therapeutics.Abbreviations: CMP: carbohydrate-mimetic peptide; CMV: cytomegalovirus; DC: dendritic cell; FDA: Food and Drug Administration; HPV: human papillomavirus; MDS: myelodysplastic syndrome; MHP: melanoma helper vaccine; NSCLC: non-small cell lung carcinoma; ODD: orphan drug designation; PPV: personalized peptide vaccination; SLP: synthetic long peptide; TAA: tumor-associated antigen; TNA: tumor neoantigen

Development of a human papillomavirus type 6/11 vaccine candidate for the prevention of condyloma acuminatum

Condyloma acuminatum (CA) represents a significant human papillomavirus (HPV) disease burden worldwide, resulting in substantial healthcare costs and loss of life quality in both genders. To address this problem, we tried to develop a bivalent HPV6/11 virus-like particle (VLP) vaccine targeting CA. HPV6/11 VLPs were generated in Hansenula polymorpha, and a disassembly and reassembly (D/R) treatment was further conducted to improve the stability and monodispersity of the VLPs. The HPV6/11 VLPs were identified by transmission electron microscopy (TEM), high performance liquid chromatography (HPLC), mass spectrum (MS) and dynamic light scattering (DLS), and were evaluated for their immunogenicity in both mice and cynomolgus monkeys. The results showed that the HPV6/11 L1 proteins were correctly expressed and assembled into HPV6/11 VLPs, and the HPV6/11 VLPs formulated with aluminum phosphate induced vigorous production of specific neutralizing antibodies against HPV6/11 VLPs in mice and cynomolgus monkeys. These data indicated that the Hansenula polymorpha-derived HPV6/11 VLPs could be formulated into a bivalent vaccine used in prevention of CA.

Phylogeny and polymorphism in the long control regions E6, E7, and L1 of HPV Type 56 in women from southwest China

Globally, human papillomavirus (HPV)‑56 accounts for a small proportion of all high‑risk HPV types; however, HPV‑56 is detected at a higher rate in Asia, particularly in southwest China. The present study analyzed polymorphisms, intratypic variants, and genetic variability in the long control regions (LCR), E6, E7, and L1 of HPV‑56 (n=75). The LCRs, E6, E7 and L1 were sequenced using a polymerase chain reaction and the sequences were submitted to GenBank. Maximum‑likelihood trees were constructed using Kimura's two‑parameter model, followed by secondary structure analysis and protein damaging prediction. Additionally, in order to assess the effect of variations in the LCR on putative binding sites for cellular proteins, MATCH server was used. Finally, the selection pressures of the E6‑E7 and L1 genes were estimated. A total of 18 point substitutions, a 42‑bp deletion and a 19‑bp deletion of LCR were identified. Some of those mutations are embedded in the putative binding sites for transcription factors. 18 single nucleotide changes occurred in the E6‑E7 sequence, 11/18 were non‑synonymous substitutions and 7/18 were synonymous mutations. A total 24 single nucleotide changes were identified in the L1 sequence, 6/24 being non‑synonymous mutations and 18/24 synonymous mutations. Selective pressure analysis predicted that the majority of mutations of HPV‑56 E6, E7 and L1 were of positive selection. The phylogenetic tree demonstrated that the isolates distributed in two lineages. Data on the prevalence and genetic variation of HPV‑56 types in southwest China may aid future studies on viral molecular mechanisms and contribute to future investigations of diagnostic probes and therapeutic vaccines.

Broadly neutralizing antiviral responses induced by a single-molecule HPV vaccine based on thermostable thioredoxin-L2 multiepitope nanoparticles

Vaccines targeting the human papillomavirus (HPV) minor capsid protein L2 are emerging as chemico-physically robust and broadly protective alternatives to the current HPV (L1-VLP) vaccines. We have previously developed a trivalent L2 vaccine prototype exploiting Pyrococcus furiosus thioredoxin (PfTrx) as a thermostable scaffold for the separate presentation of three distinct HPV L2(20–38) epitopes. With the aim of achieving a highly immunogenic, yet simpler and more GMP-production affordable formulation, we report here on a novel thermostable nanoparticle vaccine relying on genetic fusion of PfTrx-L2 with the heptamerizing coiled-coil polypeptide OVX313. A prototype HPV16 monoepitope version of this nanoparticle vaccine (PfTrx-L2-OVX313; median radius: 8.6 ± 1.0 nm) proved to be approximately 10-fold more immunogenic and with a strikingly enhanced cross-neutralization capacity compared to its monomeric counterpart. Vaccine-induced (cross-)neutralizing responses were further potentiated in a multiepitope derivative displaying eight different L2(20–38) epitopes, which elicited neutralizing antibodies against 10 different HPVs including three viral types not represented in the vaccine. Considering the prospective safety of the PfTrx scaffold and of the OVX313 heptamerization module, PfTrx-OVX313 nanoparticles lend themselves as robust L2-based immunogens with a high translational potential as a 3^rd generation HPV vaccine, but also as a novel and extremely versatile peptide-antigen presentation platform.

Type-specific human papillomavirus prevalence in cervical intraepithelial neoplasia and cancer in Iran

In Iran, human papillomavirus (HPV) vaccination is not currently included in the national vaccination program and there are no comprehensive approaches to cervical screening program. Regional data on distribution of HPV types in women is important to predict the impact of current HPV vaccines. Although several studies on distribution of HPV types in cervical precancer and cancer have been conducted in Iran, in most of them HPV positive samples were subjected to specific-primer genotyping (mainly 16 and 18), and leaving the other HPV genotypes almost undetermined. Therefore, the present study aimed to investigate the distribution of HPV types in cervical neoplasia from West and Northwest of Iran. A total of 112 women with atypia, cervical intraepithelial neoplasia, and invasive cervical cancer were included. A PCR assay was performed in all samples to detect the presence of the HPV genome using the GP5+/6+ L1 consensus primer set. All HPV positive samples were subjected for sequencing. In overall, HPV prevalence was 20% in atypica, 44.5% in cervical intraepithelial neoplasia I, 92.3% in cervical intraepithelial neoplasia II-III, and 98.2% in invasive cervical cancer. The most frequent HPV type was HPV 16 (79.2%), which was followed by HPV types 18, 6, and 33 at the frequencies of 6.5%, 5.1%, and 2.7%, respectively. The least HPV types were found to be 31, 45, 53, 58, and 66. In conclusion, this study shows that the current HPV vaccines could have great impact to reduce the burden of cervical cancer in Iran.

Prevalence of HPV infection among HIV-positive and HIV-negative women in Central/Eastern Italy: Strategies of prevention

The present cross-sectional-study aimed to determine the prevalence of human papillomavirus (HPV)-genotypes among human immunodeficiency virus (HIV)-positive and -negative women in Central/Eastern Italy, and to identify the optimal strategies for effective HPV-prevention in each group. A representative sample of HIV-negative (150/200) and -positive (50/200) women, who underwent cervico-vaginal-swabbing. Swabs were analysed for a cytological screening and for a HPV-DNA-genotyping-test. A total of 66/200 swabs resulted HPV-positive. The overall HPV-prevalence was 33% with a higher prevalence in the HIV-positive-group (48%) compared with the HIV-negative-group (28%). The most frequent genotypes were: 16, 31, 52, 58, 66, 73 and 89. Furthermore, the prevalence of specific genotypes was different in each group. The results of the present study indicate that HIV infection appears to be an independent risk factor for HPV-infection. In addition, HPV-infection is more common and more likely to persist in HIV-positive compared with in HIV-negative women. The optimal way to counteract HPV infection is through primary prevention. The stage of immunity (cluster of differentiation 4-level) at the time of the HPV-screening is one of the most important parameters for detection of susceptibility to HPV-infection and to evaluate the response to the HPV-vaccine in HIV-positive women. It may be used to determine the sub-group of HIV-positive women that are more prone to HPV-infections or that exhibit a partial response to the HPV-vaccine. At present, a novel type of vaccine with 9-genotypes is available and in the near future, it may serve an essential role in the prevention of HPV infections.

Expanded strain coverage for a highly successful public health tool: Prophylactic 9-valent human papillomavirus vaccine

Human papillomavirus is considered the causative factor for cervical cancer, which accounts for approximately 5% of the global cancer burden and more than 600,000 new cases annually that are attributable to HPV infection worldwide. The first-generation prophylactic HPV vaccines, Gardasil® and Cervarix®, were licensed approximately a decade ago. Both vaccines contain the most prevalent high-risk types, HPV16 and 18, which are associated with 70% of cervical cancer. To further increase the type coverage, 5 additional oncogenic HPV types (31, 33, 45, 52 and 58) were added to the existing Gardasil-4 to develop a 9-valent HPV vaccine (9vHPV), Gardasil 9®, increasing the potential level of protection from ∼70% to ∼90%. The efficacy of the vaccine lies primarily in its ability to elicit type-specific and neutralizing antibodies to fend off the viral infection. Therefore, type-specific and neutralizing murine monoclonal antibodies (mAbs) were used to quantitate the antigenicity of the individual vaccine antigens and to measure the antibody levels in the serum samples from vaccinees in a type- and epitope-specific manner in a competitive immunoassay. Assays for 9vHPV are extended from the proven platform used for 4vHPV by developing and adding new mAbs against the additional types. In Phase III clinical trials, comparable safety profile and immunogenicity against the original 4 types were demonstrated for the 9vHPV vaccine, and these were comparable to the 4vHPV vaccine. The efficacy of the 9vHPV vaccine was established in trials with young women. Immunobridging for younger boys and girls was performed, and the results showed higher immunogenicity in the younger age group. In a subsequent clinical trial, the 2-dose regimen of the 9vHPV vaccine used among girls and boys aged 9-14 y showed non-inferior immunogenicity to the regular 3-dose regimen for young women (aged 16-26 years). Overall, the clinical data and cost-effectiveness analysis for the 9vHPV vaccine support its widespread use to maximize the impact of this important, life-saving vaccine.

A novel candidate HPV vaccine: MS2 phage VLP displaying a tandem HPV L2 peptide offers similar protection in mice to Gardasil-9

Human papillomaviruses (HPVs) cause approximately 5% of cancer cases worldwide. Fortunately, three prophylactic vaccines have been approved to protect against HPV infections. Gardasil-9, the most recent HPV vaccine, is predicted to offer protection against the HPV types that cause ∼90% of cervical cancer, 86% of HPV-associated penile cancers, and ∼93% of HPV-associated head & neck cancers. As an alternative to Gardasil-9, we developed and tested a novel candidate vaccine targeting conserved epitopes in the HPV minor capsid protein, L2. We displayed a tandem HPV31/16L2 peptide (amino acid 17-31) or consensus peptides from HPV L2 (amino acid 69-86 or 108-122) on the surface of bacteriophage MS2 virus-like particles (VLPs). Mice immunized with the MS2 VLPs displaying the tandem peptide or immunized with a mixture of VLPs (displaying the tandem peptide and consensus peptide 69-86) elicited high titer antibodies against individual L2 epitopes. Moreover, vaccinated mice were protected from cervicovaginal infection with HPV pseudoviruses 16, 31, 45, 58 and sera from immunized mice neutralized HPV pseudoviruses 18 and 33 at levels similar to mice immunized with Gardasil-9. These results suggest that immunization with a tandem, L2 peptide or a low valency mixture of L2 peptide-displaying VLPs can provide broad protection against multiple HPV types.

Cost-effectiveness analysis of different types of human papillomavirus vaccination combined with a cervical cancer screening program in mainland China

BACKGROUND

China has a high prevalence of human papillomavirus (HPV) and a consequently high burden of disease with respect to cervical cancer. The HPV vaccine has proved to be effective in preventing cervical cancer and is now a part of routine immunization programs worldwide. It has also proved to be cost effective. This study aimed to assess the cost-effectiveness of 2-, 4-, and 9-valent HPV vaccines (hereafter, HPV2, 4 or 9) combined with current screening strategies in China.

METHODS

A Markov model was developed for a cohort of 100,000 HPV-free girls to simulate the natural history to HPV infection. Three recommended screening methods (1. liquid-based cytology test + HPV DNA test; 2. pap smear cytology test + HPV DNA test; 3. visual inspection with acetic acid) and three types of HPV vaccination program (HPV2/4/9) were incorporated into 15 intervention options, and the incremental cost-effectiveness ratio (ICER) was calculated to determine the dominant strategies. Costs, transition probabilities and utilities were obtained from a review of the literature and national databases. One-way sensitivity analyses and threshold analyses were performed for key variables in different vaccination scenarios.

RESULTS

HPV9 combined with screening showed the highest health impact in terms of reducing HPV-related diseases and increasing the number of quality-adjusted life years (QALYs). Under the current thresholds of willingness to pay (WTP, 3 times the per capita GDP or USD$ 23,880), HPV4/9 proved highly cost effective, while HPV2 combined with screening cost more and was less cost effective. Only when screening coverage increased to 60% ~ 70% did the HPV2 and screening combination strategy become economically feasible.

CONCLUSIONS

The combination of the HPV4/9 vaccine with current screening strategies for adolescent girls was highly cost-effective and had a significant impact on reducing the HPV infection-related disease burden in Mainland China.

Quantitation and biospecific identification of virus-like particles of human papillomavirus by capillary electrophoresis

Capillary electrophoresis (CE) for HPV-VLP quantitation is a very interesting alternative technique compared to those currently used in viral analysis, such as SDS-PAGE, Western blot or protein assay that are destructive and semi-quantitative or non specific. In this study, the quantitative performance of the CE method was evaluated. A main issue in virus quantitation is the absence of reference material. Therefore, the concentration of a HPV16-VLP sample produced in the laboratory was determined using ELISA with Gardasil^®, after adjuvant dissolution, as reference material and conformational H16.V5 antibody. HPV16-VLP concentration was found to influence particles electrophoretic mobility until a plateau was reached for concentrations ≤ 50µgml^-1. As zeta potential is directly proportional to the electrophoretic mobility, it was measured at different HPV-VLP concentrations and the results were in complete accordance with the measured electrophoretic mobilities. The concentration dependence of the electrophoretic mobility could be explained by an overlap of the electrical double layers of adjacent particles. The HPV16-VLP peak identity was demonstrated unequivocally by the study of HPV16-VLP/H16.V5 antibody complex formation using affinity CE. Finally, the CE method was successfully validated following the ICH Q2R1 guidelines. To overcome the sample heterogeneity issue, a well-designed sample preparation was used. Considering sample complexity, validation results were satisfactory with maximum repeatability and intermediate precision RSD of 12.2% and a maximum relative bias of 1.4%.

Looking beyond human papillomavirus (HPV) genotype 16 and 18: Defining HPV genotype distribution in cervical cancers in Australia prior to vaccination

Australia has implemented a high-coverage HPV vaccination program but has not, to date, established the distribution of HPV types that occur in cervical cancers in Australia. This information is important for determining the potential for cervical cancer prevention with both current and broader spectrum HPV vaccines. We analysed 847 cervical cancers diagnosed 2005 to 2015 in tertiary centres in the three most populous Australian states with resolution of specimens containing multiple HPV types using laser-capture microdissection. Archived FFPE tissue was reviewed by specialist pathologists, sandwich sectioned, and initially whole-tissue sections genotyped for HPV. Samples were first genotyped using SPF10-LiPA25 (version 1). Negative samples were screened with DNA ELISA kit HPV SPF10, followed by genotyping with SPF+ LiPA if ELISA positive. If still negative, samples were tested on a qPCR assay targeting the E6 region of HPV16, 18, 45 and 33. Of the 847 cancers (65.1% squamous, 28.7% adenocarcinoma, 4.3% adenosquamous, 2.0% other), 92.9% had HPV detected. Of the HPV-positive cancers, 607 of 787 (77.1%) contained HPV16 or 18, 125 of 787 (15.9%) contained HPV31/33/45/52 or 58, and 55 (7.0%) another HPV type. There was a strong correlation between HPV type and age, with younger women most likely to have HPV16/18 detected and least likely HPV negative. Our findings indicate that cervical cancers diagnosed in Australia more frequently contain HPV16/18 than in international series. This could be due to cervical screening in Australia increasing the proportion of adenocarcinomas, in which types 18 and 16 more strongly predominate, due to prevention of squamous cancers.

Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines

INTRODUCTION

Yeasts, as Eukaryotes, offer unique features for ease of growth and genetic manipulation possibilities, making it an exceptional microbial host. Areas covered: This review provides general and patent-oriented insights into production of biopharmaceuticals by yeasts. Patents, wherever possible, were correlated to the original or review articles. The review describes applications of major GRAS (generally regarded as safe) yeasts for the production of therapeutic proteins and subunit vaccines; additionally, immunomodulatory properties of yeast cell wall components were reviewed for use of whole yeast cells as a new vaccine platform. The second part of the review will discuss yeast- humanization strategies and innovative applications. Expert opinion: Biomedical applications of yeasts were initiated by utilization of Saccharomyces cerevisiae, for production of leavened (fermented) products, and advanced to serve to produce biopharmaceuticals. Higher biomass production and expression/secretion yields, more similarity of glycosylation patterns to mammals and possibility of host-improvement strategies through application of synthetic biology might enhance selection of Pichia pastoris (instead of S. cerevisiae) as a host for production of biopharmaceutical in future. Immunomodulatory properties of yeast cell wall β-glucans and possibility of intracellular expression of heterologous pathogen/tumor antigens in yeast cells have expanded their application as a new platform, 'Whole Yeast Vaccines'.

Characterization of a spray-dried candidate HPV L2-VLP vaccine stored for multiple years at room temperature

HPV infections are associated with human cancers. Although three prophylactic vaccines have been approved to protect against HPV infections, the vaccines require cold-chain storage and may not be suitable for third world countries with less developed refrigeration facilities. We previously developed a bacteriophage L2 virus-like particle (VLP)-based candidate vaccine, which elicited broadly protective antibodies against diverse HPV types. Spray-drying of MS2-16L2 VLPs into a dry powder enhanced the stability of these VLPs. Building on these studies, we assessed the long-term stability and immunogenicity of the spray-dried VLPs. Mice immunized with a single dose of spray-dried MS2-16L2 VLPs, which had been stored for 14 months at room temperature (RT), were partially protected from challenge with a high dose of HPV16, one year after immunization. However, immunization with two doses of MS2-16L2 VLPs stored at RT for 34 months elicited high titer anti-HPV antibodies. More importantly, this group of mice showed significant protection from HPV16, 4 months after immunization. These results suggest that spray-dried MS2-16L2 VLPs retain their effectiveness after long-term storage at RT, and may be suitable in third world countries with less developed refrigeration facilities.

Development and Characterization of an HPV Type-16 Specific Modified DNA Aptamer for the Improvement of Potency Assays

Measuring vaccine potency is critical for vaccine release and is often accomplished using antibody-based ELISAs. Antibodies can be associated with significant drawbacks that are often overlooked including lot-to-lot variability, problems with cell-line maintenance, limited stability, high cost, and long discovery lead times. Here, we address many of these issues through the development of an aptamer, known as a slow off-rate modified DNA aptamer (SOMAmer), which targets a vaccine antigen in the human papillomavirus (HPV) vaccine Gardasil. The aptamer, termed HPV-07, was selected to bind the Type 16 virus-like-particle (VLP) formed by the self-assembling capsid protein L1. It is capable of binding with high sensitivity (EC₅₀ of 0.1 to 0.4 μg/mL depending on assay format) while strongly discriminating against other VLP types. The aptamer competes for binding with the neutralizing antibody H16.V5, indicating at least partial recognition of a neutralizing and clinically relevant epitope. This makes it a useful reagent for measuring both potency and stability. When used in an ELISA format, the aptamer displays both high precision (intermediate precision of 6.3%) and a large linear range spanning from 25% to 200% of a typical formulation. To further exploit the advantages of aptamers, a simplified mix and read assay was also developed. This assay format offers significant time and resource reductions compared to a traditional ELISA. These results show aptamers are suitable reagents for biological potency assays, and we expect that their implementation could improve upon current assay formats.

Factors associated with parents' attitudes to the HPV vaccination of their adolescent sons : A systematic review

OBJECTIVE

The objective of the study was to identify factors associated with human papilloma virus (HPV) vaccine acceptability in parents of adolescent boys. This information is critical to the development of approaches to optimise HPV vaccine uptake among this population group.

METHODS

We performed a systematic search of the literature in addressing factors influencing parental attitudes to and beliefs about HPV vaccine and its acceptability for use. The findings were organised within the framework of the Health Belief Model (HBM) and summarised using a semi quantitative method.

RESULTS

Eighteen studies met the inclusion criteria. Parental decisions were predominantly shaped by the perceived benefits of the vaccine; perceived risk of sons contracting the HPV infection, and having recommendations from health care providers. Fear of side effects and uncertainty about vaccine effectiveness, as well as cost and lack of healthcare, were barriers to HPV vaccination. Other factors such as knowledge, family characteristics, parent-child dialogue and egalitarian values appeared to be important when deciding whether to vaccinate boys.

CONCLUSIONS

HPV vaccine uptake among male adolescents is suboptimal. Future programs need to address the predictors of uptake by educating parents about the boys' high susceptibility to infection, the benefits of vaccination, and reduce concerns regarding perceived barriers. Additionally, uptake may be facilitated by encouraging health care provider endorsement, particularly in countries without government-funded immunisation programs.

Spotlight on the 9-valent HPV vaccine

Starting in 2006, vaccination against human papillomavirus (HPV) has been progressively implemented in most developed countries. Two vaccines have been successfully used, a bivalent vaccine targeting HPV-related cancers (bHPV) and a quadrivalent vaccine (qHPV) targeting both HPV-related cancers and genital warts. Between December 2014 and June 2015, a new nonavalent HPV vaccine (9vHPV) was granted marketing authorization in the USA and Europe. The 9vHPV was developed from the qHPV and includes five additional HPV types that should increase the level of protection toward HPV-related cancers. Efficacy and/or immunogenicity of 9vHPV has been assessed in eight clinical studies. The 9vHPV vaccine induced a very robust immune response against all vaccine types, with seroconversion rates close to 100%. The safety profile of 9vHPV is comparable to that of qHPV. Local reactions, especially swelling, have been more frequently reported after 9vHPV than qHPV, and this slightly increases when the 9vHPV is coadministered with other vaccines. The additional coverage offered by the 9vHPV may prevent a significant proportion of HPV-related cancers (variable between 8% and 18%) depending on the local distribution of high-risk HPV types in the population. It is impossible, at present, to anticipate the actual impact of the wide use of the 9vHPV in comparison with the bHPV or the qHPV, since it depends on many variables including duration of protection, potential cross-protection toward nonvaccine types, and herd immunity effect.

Immunotherapeutic strategies for sexually transmitted viral infections: HIV, HSV and HPV

More than 1 million sexually transmitted infections (STIs) are acquired each day globally. Etiotropic drugs cannot effectively control infectious diseases therefore, there is a dire need to explore alternative strategies especially those based on the regulation of immune system. The review discusses all rational approaches to develop better understanding towards immunotherapeutic strategies based on modulation of immune system in an attempt to curb the elevating risk of infectious diseases such as HIV, HPV and HSV because of their high prevalence. Development of monoclonal antibodies, vaccines and several other immune based treatments are promising alternative strategies that are offering new opportunities to eradicate pathogens.