Global Delivery of Human Papillomavirus Vaccines

Melt Processing Virus-Like Particle-Based Vaccine Candidates into Biodegradable Polymer Implants

Melt processing is an emerging production method to efficiently encapsulate proteins into polymeric devices for sustained release. In the context of vaccines, melt processing is well-suited to develop vaccine delivery devices that are stable outside the cold chain and can generate protective immunity from a single dose. We have demonstrated the compatibility of bacteriophage Qβ virus-like particles (VLPs) with hot-melt extrusion (HME) and have leveraged this technology to develop a single-dose vaccine candidate for vaccination against human papillomavirus (HPV). Here, we detail the methods for chemically conjugating an HPV peptide epitope from the L2 minor capsid protein to Qβ VLPs to generate HPV-Qβ particles. We outline techniques used to characterize HPV-Qβ particles, and we elaborate on the process to encapsulate HPV-Qβ into biodegradable poly(lactic-co-glycolic acid) (PLGA) implants and discuss methods for the materials characterization of the HPV-Qβ/polymer melts. The methods described could be adapted to other disease targets, i.e., by conjugation of a different peptide epitope, or transferred to other VLP systems suited for conjugation, immune response, or stability during processing. Such VLPs are ideally suited for use in HME, a mature, scalable, continuous, and solvent-free process which can be adapted to mold devices, therefore allowing the processing of the melts into various geometries, such as subcutaneous implants, or self-administrable microneedle patches.

Dissolving Microneedle Delivery of a Prophylactic HPV Vaccine

Prophylactic vaccines capable of preventing human papillomavirus (HPV) infections are still inaccessible to a vast majority of the global population due to their high cost and challenges related to multiple administrations performed in a medical setting. In an effort to improve distribution and administration, we have developed dissolvable microneedles loaded with a thermally stable HPV vaccine candidate consisting of Qβ virus-like particles (VLPs) displaying a highly conserved epitope from the L2 protein of HPV (Qβ-HPV). Polymeric microneedle delivery of Qβ-HPV produces similar amounts of anti-HPV16 L2 IgG antibodies compared to traditional subcutaneous injection while delivering a much smaller amount of intradermal dose. However, a dose sparing effect was found. Furthermore, immunization yielded neutralizing antibody responses in a HPV pseudovirus assay. The vaccine candidate was confirmed to be stable at room temperature after storage for several months, potentially mitigating many of the challenges associated with cold-chain distribution. The ease of self-administration and minimal invasiveness of such microneedle patch vaccines may enable wide-scale distribution of the HPV vaccine and lead to higher patient compliance. The Qβ VLP and its delivery technology is a plug-and-play system that could serve as a universal platform with a broad range of applications. Qβ VLPs may be stockpiled for conjugation to a wide range of epitopes, which are then packaged and delivered directly to the patient via noninvasive microneedle patches. Such a system paves the way for rapid distribution and self-administration of vaccines.

Feasibility and acceptability of nationwide HPV vaccine introduction in Senegal: Findings from community-level cross-sectional surveys, 2020

In Senegal, cervical cancer is the most common cancer among women and the leading cause of morbidity and mortality from all cancers. In 2018, Senegal launched a national human papillomavirus (HPV) vaccination program with Gavi, the Vaccine Alliance (Gavi), support. HPV vaccination was incorporated into the national immunization program as a two-dose schedule, with a 6-12-month interval, to nine-year-old girls via routine immunization (RI) services at health facilities, schools and community outreach services throughout the year. During February to March 2020, we conducted interviews to assess the awareness, feasibility, and acceptability of the HPV vaccination program with a cross-sectional convenience sample of healthcare workers (HCWs), school personnel, community healthcare workers (cHCWs), parents, and community leaders from 77 rural and urban health facility catchment areas. Participants were asked questions on HPV vaccine knowledge, delivery, training, and community acceptability of the program. We conducted a descriptive analysis stratified by respondent type. Data were collected from 465 individuals: 77 HCW, 78 school personnel, 78 cHCWs, 152 parents, and community leaders. The majority of HCWs (83.1%) and cHCWs (74.4%) and school personnel (57.7%) attended a training on HPV vaccine before program launch. Of all respondents, most (52.5-87.2%) were able to correctly identify the target population. The majority of respondents (60.2-77.5%) felt that the vaccine was very accepted or accepted in the community. Senegal's HPV vaccine introduction program, among the first national programs in the African region, was accepted by community stakeholders. Training rates were high, and most respondents identified the target population correctly. However, continued technical support is needed for the integration of HPV vaccination as a RI activity for this non-traditional age group. The Senegal experience can be a useful resource for countries planning to introduce the HPV vaccine.

Tanzania's human papillomavirus (HPV) vaccination program: Community awareness, feasibility, and acceptability of a national HPV vaccination program, 2019

BACKGROUND

In April 2018, Tanzania introduced the human papillomavirus (HPV) vaccine nationally to 14-year-old girls, utilizing routine delivery strategies (i.e. vaccinating girls at health facilities and community outreach, including schools). We sought to assess awareness, feasibility, and acceptability of the HPV vaccination program among health workers and community-level stakeholders.

METHODS

We conducted cross-sectional in-person surveys among health workers, school personnel, community leaders, and council leaders in 18 council areas across six regions of Tanzania in October-November 2019. Regions were purposively selected to provide demographic, geographic, and vaccination coverage variability; sub-regional levels used random or stratified random sampling. Surveys included questions on HPV vaccine training and knowledge, delivery strategy, target population, and vaccine and program acceptability. Descriptive analysis was completed for all variables stratified by respondent groups.

RESULTS

Across the 18 councils, there were 461 respondents, including health workers (165), school personnel (135), community leaders (143), and council leaders (18). Over half of each respondent group (50-78%) attended a training or orientation on HPV vaccine. Almost 75% of the health workers and school personnel respondent groups, and less than half (45%) of community leaders correctly identified the target age group for HPV vaccine. Most (80%) of the health workers indicated HPV vaccination was available at health facilities and schools; most (79%) indicated that the majority of girls receive HPV vaccine in school. Approximately half (52%) of all respondents reported hearing misinformation about HPV vaccine, but 97% of all respondents indicated that HPV vaccine was either "very accepted" or "somewhat accepted" in their community.

CONCLUSION

The HPV vaccination program in Tanzania was well accepted by community stakeholders in 18 councils; adequate knowledge of HPV vaccine and the HPV vaccination program was demonstrated by health workers and school personnel. However, continued technical support for integration of HPV vaccination as a routine immunization activity and reinforcement of basic knowledge about HPV vaccine in specific community groups is needed. The Tanzania experience provides an example of how this vaccine can be integrated into routine immunization delivery strategies and can be a useful resource for countries planning to introduce HPV vaccine as well as informing global partners on how to best support to countries in operationalizing their HPV vaccine introduction plans.

National introduction of human papillomavirus (HPV) vaccine in Tanzania: Programmatic decision-making and implementation

Background:

Cervical cancer is the leading cause of cancer among women in Tanzania, with approximately 10,000 new cases and 7,000 deaths annually. In April 2018, the Government of Tanzania introduced 2 doses of human papillomavirus (HPV) vaccine nationally to adolescent girls to prevent cervical cancer, following a successful 2-year pilot introduction of the vaccine in the Kilimanjaro Region.

Methods:

We interviewed key informants at the national level in Tanzania from February to November 2019, using a semi-structured tool to better understand national decision-making and program implementation. We conducted a comprehensive desk review of HPV vaccine introduction materials and reviewed administrative coverage data.

Results:

Ten key informants were interviewed from the Ministry of Health, Community Development, Gender, Elderly, and Children, the World Health Organization, and other partners, and HPV vaccine planning documents and administrative coverage data were reviewed during the desk review. Tanzania introduced HPV vaccine to a single-age cohort of 14-year-old girls, with the decision-making process involving the Tanzania Immunization Technical Advisory Group and the national Interagency Coordination Committee. HPV vaccine was integrated into the routine immunization delivery strategy, available at health facilities and through outreach services at community sites, community mobile sites (>10 km from the health facility), and primary and secondary schools. Pre-introduction activities included trainings and microplanning workshops for health workers and school personnel at the national, regional, council, and health facility levels. Over 6,000 health workers and 22,000 school personnel were trained nationwide. Stakeholder and primary health care committee meetings were also conducted at the national level and in each of the regions as part of the advocacy and communication strategy. Administrative coverage of the first dose of HPV vaccine at the end of 2019 was 78%, and second dose coverage was 49%. No adverse events following HPV vaccination were reported to the national level.

Discussion:

Tanzania successfully introduced HPV vaccine nationally targeting 14-year-old girls, using routine delivery strategies. Continued monitoring of vaccination coverage will be important to ensure full 2-dose vaccination of eligible girls. Tanzania can consider periodic intensified vaccination and targeted social mobilization efforts, as needed.

HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010-2019

WHO/UNICEF estimates for HPV vaccination coverage from 2010 to 2019 are analyzed against the backdrop of the 90% coverage target for HPV vaccination by 2030 set in the recently approved global strategy for cervical cancer elimination as a public health problem. As of June 2020, 107 (55%) of the 194 WHO Member States have introduced HPV vaccination. The Americas and Europe are by far the WHO regions with the most introductions, 85% and 77% of their countries having already introduced respectively. A record number of introductions was observed in 2019, most of which in low- and middle- income countries (LMIC) where access has been limited. Programs had an average performance coverage of around 67% for the first dose and 53% for the final dose of HPV. LMICs performed on average better than high- income countries for the first dose, but worse for the last dose due to higher dropout. Only 5 (6%) countries achieved coverages with the final dose of more than 90%, 22 countries (21%) achieved coverages of 75% or higher while 35 (40%) had a final dose coverage of 50% or less. When expressed as world population coverage (i.e., weighted by population size), global coverage of the final HPV dose for 2019 is estimated at 15%. There is a long way to go to meet the 2030 elimination target of 90%. In the post-COVID era attention should be paid to maintain the pace of introductions, specially ensuring the most populous countries introduce, and further improving program performance globally.

Ortega-Rivera O, Ray S, K. Pokorski J, F. Steinmetz N. A Scalable Manufacturing Approach to Single Dose Vaccination against HPV

Human papillomavirus (HPV) is a globally prevalent sexually-transmitted pathogen, responsible for most cases of cervical cancer. HPV vaccination rates remain suboptimal, partly due to the need for multiple doses, leading to a lack of compliance and incomplete protection. To address the drawbacks of current HPV vaccines, we used a scalable manufacturing process to prepare implantable polymer-protein blends for single-administration with sustained delivery. Peptide epitopes from HPV16 capsid protein L2 were conjugated to the virus-like particles derived from bacteriophage Qβ, to enhance their immunogenicity. The HPV-Qβ particles were then encapsulated into poly(lactic-co-glycolic acid) (PLGA) implants, using a benchtop melt-processing system. The implants facilitated the slow and sustained release of HPV-Qβ particles without the loss of nanoparticle integrity, during high temperature melt processing. Mice vaccinated with the implants generated IgG titers comparable to the traditional soluble injections and achieved protection in a pseudovirus neutralization assay. HPV-Qβ implants offer a new vaccination platform; because the melt-processing is so versatile, the technology offers the opportunity for massive upscale into any geometric form factor. Notably, microneedle patches would allow for self-administration in the absence of a healthcare professional, within the developing world. The Qβ technology is highly adaptable, allowing the production of vaccine candidates and their delivery devices for multiple strains or types of viruses.

Long-term immunogenicity, effectiveness, and safety of nine-valent human papillomavirus vaccine in girls and boys 9 to 15 years of age: Interim analysis after 8 years of follow-up

BACKGROUND

The nine-valent human papillomavirus (9vHPV) vaccine protects against infection and disease related to HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. The pivotal 36-month Phase III immunogenicity study of 9vHPV vaccine in 9- to 15-year-old girls and boys was extended to assess long-term immunogenicity and effectiveness through approximately 10 years after vaccination. We describe results of an interim analysis based on approximately 8 years of follow-up after vaccination.

METHODS

Participants aged 9-15 years who received three doses of 9vHPV vaccine (at day 1, month 2, and month 6) in the base study and consented to follow-up were enrolled in the long-term follow-up study extension (N = 1272 [females, n = 971; males, n = 301]). Serum was collected at months 66 and 90 to assess antibody responses. For effectiveness analysis, genital swabs were collected (to assess HPV DNA by polymerase chain reaction [PCR]) and external genital examination was conducted (to detect external genital lesions) every 6 months starting when the participant reached 16 years of age. Cervical cytology tests were conducted annually when female participants reached 21 years of age; participants with cytological abnormalities were triaged to colposcopy based on a protocol-specified algorithm. External genital and cervical biopsies of abnormal lesions were performed, and histological diagnoses were adjudicated by a pathology panel. Specimens were tested by PCR to detect HPV DNA.

RESULTS

Geometric mean titers for each 9vHPV vaccine HPV type peaked around month 7 and gradually decreased through month 90. Seropositivity rates remained >90% through month 90 for each of the 9vHPV vaccine types by HPV immunoglobulin Luminex Immunoassay. No cases of HPV6/11/16/18/31/33/45/52/58-related high-grade intraepithelial neoplasia or genital warts were observed in the per-protocol population (n = 1107) based on a maximum follow-up of 8.2 years (median 7.6 years) post-Dose 3. Incidence rates of HPV6/11/16/18/31/33/45/52/58-related 6-month persistent infection in females and males were 49.2 and 37.3 per 10,000 person-years, respectively, which were within ranges expected in vaccinated cohorts. There were no vaccine-related SAEs or deaths during the period covered by this interim analysis.

CONCLUSIONS

The 9vHPV vaccine provided sustained immunogenicity and durable effectiveness through approximately 7 and 8 years, respectively, following vaccination of girls and boys aged 9-15 years.

Parent-Level Barriers and Facilitators to HPV Vaccine Implementation in Santo Domingo, Dominican Republic

Cervical cancer is the second leading cause of cancer death for women in the Dominican Republic. Vaccination against human papillomavirus (HPV) could reduce mortality from cervical cancer globally by as much as 90%. The purpose of our study was to explore multi-level barriers and facilitators to implementation of a national HPV vaccine program in the Dominican Republic; this article focuses on parent-level barriers and facilitators. In this qualitative study, we conducted six focus groups (N = 64) with parents of school-age children in the Santo Domingo area of the Dominican Republic, representing diverse socioeconomic groups and geographic settings. Thematic content analysis, using inductive and deductive approaches, was done following transcription and translation of audio-recordings from focus group discussions. Among this group of parents in the Santo Domingo area, facilitators to vaccine uptake were favorable attitudes towards vaccines in general and concern about cervical cancer as a health issue. Barriers found were low to moderate knowledge of HPV and cervical cancer, especially in the rural and suburban groups, and cost and lack of public awareness of the vaccine. This study identified key barriers and facilitators to HPV vaccine implementation in the Dominican Republic. Health messaging, incorporating specialist providers as opinion leaders, will need to be tailored to broad audiences with varying levels of information and awareness, anticipating misinformation and concerns, and will need to emphasize HPV vaccine as a method to prevent cancer.

Racial and Ethnic Variation Associated With Human Papillomavirus Genotype in Anal Dysplasia

BACKGROUND

Human Papillomavirus (HPV) is known to cause dysplasia and cancer. In cervical disease, there are documented differences in prevalence of HPV genotypes among racial/ethnic groups. Little is known about prevalence of HPV genotypes in anal dysplasia. This study aimed to evaluate association between HPV genotypes and race/ethnicity in a racially heterogenous population with anal dysplasia.

METHODS

This was a single-institution retrospective review of patients treated for anal dysplasia between 2008 and 2019. HPV genotype, obtained via anal swab testing, was recorded as HPV 16, HPV 18, or other non-16/18 high-risk (HR) HPV genotypes. Univariate and multivariate logistic regression analyses were used to evaluate the association between patient factors and HPV genotype.

RESULTS

Of 517 patients meeting inclusion criteria, 46.8% identified as White, 37.1% as Black, 13.2% as Hispanic, and 2.9% as other/unknown. Race/ethnicity (P = 0.016) and sex (P < 0.001) were significantly associated with differences in prevalence of HPV genotypes. Black (odds ratio 1.56, 95% confidence interval 1.00-2.44) and male (odds ratio 2.35, 95% confidence interval 1.42-3.92) patients were significantly more likely to have non-16/18 HR HPV genotypes.

CONCLUSIONS

In a racially and socioeconomically diverse cohort of patients with anal dysplasia, Black race and male sex were associated with increased likelihood of infection with a non-16/18 HR HPV genotype. Many of these genotypes are not covered by currently available vaccines. Further study is warranted to evaluate anal HPV genotypes in a larger cohort, as this may have important implications in HPV vaccination and anal dysplasia screening efforts.

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.

Japanese physicians' attitudes and intentions regarding human papillomavirus vaccine compared with other adolescent vaccines

INTRODUCTION

Japan has experienced extremely low human papillomavirus vaccine (HPVV) coverage following the suspension of proactive governmental recommendations in 2013. Several studies have reported that recommendations from physicians increase adolescents' vaccine acceptance. In this survey, we evaluated the attitudes and intentions of Japanese physicians related to adolescent immunizations, particularly HPVV.

METHODS

We conducted a cross-sectional study using a mailed questionnaire targeting 330 Japanese physicians including 78 pediatricians, 225 internists and 27 obstetricians and gynecologists (OB/GYNs) in Kawasaki City, Japan in 2016. The survey measured physicians' reported frequency of educating adolescents about vaccines as well as their own perceptions and intentions related to adolescent immunizations.

RESULTS

Valid responses were obtained from 148 (45%) physicians. Though 53% agreed that the HPVV should be recommended, only 21% reported educating about HPVV. The majority of respondents (90%) agreed that they would restart HPVV for adolescents if the government reinstated its recommendation.

CONCLUSIONS

Although Japanese physicians reported support for adolescent immunizations, they were less likely to recommend or discuss HPVV compared with other adolescent vaccines. Responses indicated this was, at least in part, due to the lack of governmental support for HPVV, indicating that their recommendations would improve with government endorsement of the vaccine.

Efficacy, immunogenicity, and safety of a 9-valent human papillomavirus vaccine in Latin American girls, boys, and young women

BACKGROUND

A 9-valent human papillomavirus (HPV6/11/16/18/31/33/45/52/58; 9vHPV) vaccine was developed to expand coverage of the previously developed quadrivalent (HPV6/11/16/18; qHPV) vaccine.

METHODS

Efficacy, immunogenicity, and safety outcomes were assessed in Latin American participants enrolled in 2 international studies of the 9vHPV vaccine, including a randomized, double-blinded, controlled with qHPV vaccine, efficacy, immunogenicity, and safety study in young women aged 16-26 years, and an immunogenicity and safety study in girls and boys aged 9-15 years. Participants (N=5312) received vaccination at Day 1, Month 2, and Month 6. Gynecological swabs were collected regularly in young women for cytological and HPV DNA testing. Serum was analyzed for HPV antibodies in all participants. Adverse events (AEs) were also monitored in all participants.

RESULTS

The 9vHPV vaccine prevented HPV 31-, 33-, 45-, 52-, and 58-related high-grade cervical, vulvar, and vaginal dysplasia with 92.3% efficacy (95% confidence interval 54.4, 99.6). Anti-HPV6, 11, 16, and 18 geometric mean titers at Month 7 were similar in the 9vHPV and qHPV vaccination groups. Anti-HPV antibody responses following vaccination were higher among girls and boys than in young women. Most (>99%) 9vHPV vaccine recipients seroconverted for all 9 HPV types at Month 7. Antibody responses to the 9 HPV types persisted over 5 years. The most common AEs were injection-site related, mostly of mild to moderate intensity.

CONCLUSIONS

The 9vHPV vaccine is efficacious, immunogenic, and well tolerated in Latin American young women, girls, and boys. These data support 9vHPV vaccination programs in Latin America, a region with substantial cervical cancer burden.

Factors associated with the human papillomavirus (HPV) vaccination across three countries following vaccination introduction

Direct international comparisons which aim to understand how factors associated with human papillomavirus (HPV) vaccine initiation and attitudes towards the HPV vaccination in parents differ are scarce. Parents (n = 179) of daughters aged 9-17 years in the US, UK and Australia completed an online survey in 2011 with questions measuring daughters' HPV vaccination status, HPV knowledge, HPV vaccination knowledge, and statements assessing attitude towards the HPV vaccine. The strongest factor associated with vaccination status across all countries was parental HPV knowledge (p < 0.001). Parents with both very low and very high knowledge scores were less likely to have vaccinated their daughters. Parents with higher HPV vaccination knowledge scores intended to vaccinate their daughters (if not already vaccinated) for protective reasons (p < 0.001), while those whose daughters were already vaccinated understood that vaccination protection was not 100% and that their daughters may still be at risk of getting HPV (p < 0.05). Compared to the UK and Australia, a higher proportion of parents with unvaccinated daughters from the US were worried about the side-effects of the HPV vaccination (US: 60.5%, UK: 36.4%, AUS: 15.4%; p < 0.05), believed that getting the vaccination might be a hassle (US: 21.1%, UK: 0%, AUS: 7.7%; p < 0.05), and that the vaccine was too new (US: 44.7%, UK: 22.7%, AUS: 7.7%; p < 0.05). This study adds to the understanding of how parents may influence vaccination uptake by demonstrating the effect of knowledge and the parental attitudes towards HPV vaccination across three countries.

9-Valent human papillomavirus vaccine: a review of the clinical development program

INTRODUCTION

The 9-valent human papillomavirus (9vHPV) vaccine covers the same HPV types (6/11/16/18) as the quadrivalent HPV (qHPV) vaccine and 5 additional cancer-causing types (31/33/45/52/58). Epidemiological studies indicate that the 9vHPV vaccine could prevent approximately 90% of cervical cancers, 70-85% of high-grade cervical dysplasia (precancers), 85-95% of HPV-related vulvar, vaginal, and anal cancers, and 90% of genital warts. Areas covered: Study design features and key findings from the 9vHPV vaccine clinical development program are reviewed. In particular, 9vHPV vaccine efficacy was established in a Phase III study in young women age 16-26 years. Efficacy results in young women were extrapolated to pre- and young adolescent girls and boys and young men by immunological bridging (i.e., demonstration of non-inferior immunogenicity in these groups versus young women). Expert commentary: The development of the 9vHPV vaccine is the outcome of 20 years of continuous clinical research. Broad vaccination programs could help substantially decrease the incidence of HPV-related disease.

Impact of baseline covariates on the immunogenicity of the 9-valent HPV vaccine - A combined analysis of five phase III clinical trials

BACKGROUND

The immunogenicity profile of the 9-valent HPV (9vHPV) vaccine was evaluated across five phase III clinical studies conducted in girls and boys 9-15 years of age and young women 16-26 years of age. The effect of baseline characteristics of subjects on vaccine-induced HPV antibody responses was assessed.

METHODS

Immunogenicity data from 11,304 subjects who received ≥1 dose of 9vHPV vaccine in five Phase III studies were analyzed. Vaccine was administered as a 3-dose regimen. HPV antibody titers were assessed 1 month after dose 3 using a competitive Luminex immunoassay and summarized as geometric mean titers (GMTs). Covariates examined were age, gender, race, region of residence, and HPV serostatus and PCR status at day 1.

RESULTS

GMTs to all 9 vaccine HPV types decreased with age at vaccination initiation, and were otherwise generally similar among the demographic subgroups defined by gender, race and region of residence. For all subgroups defined by race or region of residence, GMTs were higher in girls and boys than in young women. Vaccination of subjects who were seropositive at day 1 to a vaccine HPV type resulted in higher GMTs to that type, compared with those in subjects who were seronegative for that type at day 1.

CONCLUSIONS

9vHPV vaccine immunogenicity was robust among subjects with differing baseline characteristics. It was generally comparable across subjects of different races and from different regions. Greater immunogenicity in girls and boys versus young women (the population used to establish 9vHPV vaccine efficacy in clinical studies) indicates that the anti-HPV responses generated by the vaccine in adolescents from all races or regions were sufficient to induce high-level protective efficacy. This immunogenicity profile supports a widespread 9vHPV vaccination program and early vaccination.

Vaccine strategies: Optimising outcomes

Successful immunisation programmes generally result from high vaccine effectiveness and adequate uptake of vaccines. In the development of new vaccination strategies, the structure and strength of the local healthcare system is a key consideration. In high income countries, existing infrastructures are usually used, while in less developed countries, the capacity for introducing new vaccines may need to be strengthened, particularly for vaccines administered beyond early childhood, such as the measles or human papillomavirus (HPV) vaccine. Reliable immunisation service funding is another important factor and low income countries often need external supplementary sources of finance. Many regions also obtain support in generating an evidence base for vaccination via initiatives created by organisations including World Health Organization (WHO), the Pan American Health Organization (PAHO), the Agence de Médecine Préventive and the Sabin Vaccine Institute. Strong monitoring and surveillance mechanisms are also required. An example is the efficient and low-cost approaches for measuring the impact of the hepatitis B control initiative and evaluating achievement of goals that have been established in the WHO Western Pacific region. A review of implementation strategies reveals differing degrees of success. For example, in the Americas, PAHO advanced a measles-mumps-rubella vaccine strategy, targeting different population groups in mass, catch-up and follow-up vaccination campaigns. This has had much success but coverage data from some parts of the region suggest that children are still not receiving all appropriate vaccines, highlighting problems with local service infrastructures. Stark differences in coverage levels are also observed among high income countries, as is the case with HPV vaccine implementation in the USA versus the UK and Australia, reflecting differences in delivery settings. Experience and research have shown which vaccine strategies work well and the factors that encourage success, which often include strong support from government and healthcare organisations, as well as tailored, culturally-appropriate local approaches to optimise outcomes.

Tempest in a teapot: A systematic review of HPV vaccination and risk compensation research

There has been some concern among parents and in the media that vaccinating children against human papillomavirus could be seen as giving children permission to engage in risky sexual behaviors (also known as sexual disinhibition). Several studies have found this concern to be unfounded but there have been no attempts to synthesize the relevant studies in order to assess if there is evidence of sexual disinhibition. The aim of this study was to synthesize recent literature examining sexual behaviors and biological outcomes (e.g., sexually transmitted infections) post-HPV vaccination. We reviewed literature from January 1, 2008-June 30, 2015 using PubMed, CINAHL, and Embase with the following search terms: [(sex behavior OR sex behavior OR sexual) AND (human papillomavirus OR HPV) AND (vaccines OR vaccine OR vaccination)] followed by a cited reference search. We included studies that examined biological outcomes and reported behaviors post-vaccination in both males and females. Studies were reviewed by title and abstract and relevant studies were examined as full-text articles. We identified 2,503 articles and 20 were eventually included in the review. None of the studies of sexual behaviors and/or biological outcomes found evidence of riskier behaviors or higher rates of STIs after HPV vaccination. Instead, the studies found that vaccinated compared to unvaccinated individuals were less likely to report vaginal intercourse without a condom (OR = 0.5; 95%CI = 0.4-0.6) and non-use of contraception (OR = 0.27; 95%CI = 0.15-0.48) and unvaccinated participants had higher rates of Chlamydia (OR = 2.3; 95%CI = 1.06-5.00). These results should be reassuring to parents and health care providers.

HPV vaccines: how many doses are needed for protection?

HPV virus-like particle vaccines are highly immunogenic, well tolerated and are in the national immunization programs in more than 62 countries. Genital HPV is a sexually transmitted infection with first infection occurring just after the onset of sexual activity. The routine cohort for immunization in almost all countries are adolescent girls 9–15 years of age with or without catch-up for older adolescents and young women. In countries with vaccine coverage exceeding 50%, reductions in vaccine type HPV geno-prevalence and disease are being shown. The mechanism of protection is assumed to be via neutralizing antibody. Antibody concentration in adolescents less than 14 years of age after two doses of vaccine at 0 and 6 months are noninferior to women after three doses and in whom efficacy was demonstrated in randomized control trials. The original three-dose schedules have already been reduced in many countries, for those 14 years of age and under, to two doses at least 6 months apart for the licensed vaccines Cervarix® and GARDASIL®. There is preliminary evidence that one dose of vaccine is as effective as two or three doses at preventing persistent HPV infection in the cervix in young women and a one-dose schedule may be possible if supported by evidence from randomized controlled trials.