Immunization of early adolescent females with human papillomavirus type 16 and 18 L1 virus-like particle vaccine containing AS04 adjuvant

Mechanisms of antibody-dependent enhancement of infectious disease

Antibody-dependent enhancement (ADE) of infectious disease is a phenomenon whereby host antibodies increase the severity of an infection. It is well established in viral infections but ADE also has an underappreciated role during bacterial, fungal and parasitic infections. ADE can occur during both primary infections and re-infections with the same or a related pathogen; therefore, understanding the underlying mechanisms of ADE is critical for understanding the pathogenesis and progression of many infectious diseases. Here, we review the four distinct mechanisms by which antibodies increase disease severity during an infection. We discuss the most established mechanistic explanation for ADE, where cross-reactive, disease-enhancing antibodies bound to pathogens interact with Fc receptors, thereby enhancing pathogen entry or replication, ultimately increasing the total pathogen load. Additionally, we explore how some pathogenic antibodies can shield bacteria from complement-dependent killing, thereby enhancing bacterial survival. We interrogate the molecular mechanisms by which antibodies can amplify inflammation to drive severe disease, even in the absence of increased pathogen replication. We also examine emerging roles for autoantibodies in enhancing the pathogenesis of infectious diseases. Finally, we discuss how we can leverage these insights to improve vaccine design and future treatments for infectious diseases.

Immune response following a two-dose schedule of bivalent HPV vaccination among girls and boys

Background

This longitudinal cohort study describes the kinetics in antibody levels after two doses of the bivalent human papillomavirus (HPV) vaccine in girls (birth cohort 2001) vaccinated in the routine Dutch vaccination program at 12 years of age, up to 7.5 years post-vaccination. Also, the antibody response one month post-vaccination of the first cohort of boys (birth cohort 2012, vaccinated at 10 years of age) eligible for HPV vaccination in the Netherlands is presented.

Method

Blood samples and questionnaire data were collected of girls and boys. HPV type-specific antibody concentrations (LU/mL) against HPV16/18/31/33/45/52/58 were assessed using a validated virus-like particle (VLP) multiplex immunoassay. For girls, antibody decays over time were modelled using the modified power-law decay model and the exponential decay model.

Results

The Geometric Mean Concentrations (GMCs) remained higher for HPV16/18 than for HPV types 31, 33, 45, 52, and 58 among girls up to 7.5 years post-vaccination. The antibody levels of HPV16 and HPV18 reached plateau values of 482 and 159 LU/mL, respectively. Mathematical modelling showed that the half-life values of HPV16/18 were 2.4- to 4.5-fold higher compared with the half-life values of the other HPV types. Among boys (aged 10 years), the GMC for HPV16 was significantly higher than among girls one month post-vaccination (aged 12 years).

Conclusion

The GMCs of all HPV types declined over time, although the GMCs of HPV16/18 remained relatively high up to 7.5 years post-vaccination. The GMCs for HPV16/18 among boys were at least equally high as the GMCs among girls at one month post-vaccination. Further follow-up of the cohort of boys is needed to gain knowledge on long-term immune responses of young boys following bivalent HPV vaccination.

U.S. Vietnamese parents' trusted sources of information and preferences for intervention messaging about HPV vaccination: A mixed methods study

Objective

Assess trusted sources of information, perceived message effectiveness, and preferred dissemination strategies regarding adolescent HPV vaccination among U.S. Vietnamese parents.

Methods

Data came from an observational, explanatory sequential mixed-methods study with U.S. Vietnamese parents of adolescents (408 survey participants; 32 interview participants). Surveys and interviews were conducted in both Vietnamese and English. Mixed-methods data were integrated and analyzed for confirmation, expansion, or discordance.

Results

Both quantitative and qualitative findings confirm high trust in HPV vaccination information from providers, government agencies, and cancer organizations. Messages perceived as effective emphasize vaccine safety, experts' endorsement, importance of vaccination prior to HPV exposure, and preventable cancers. Qualitative findings expanded quantitative results, demonstrating a desire for evidence-based information in the Vietnamese language and addressing cultural concerns (e.g., effectiveness or potential side effects specific to Vietnamese adolescents, whether parents should delay HPV vaccination for Vietnamese adolescents). Quantitative and qualitative findings were incongruent about whether parents would trust information about HPV vaccination that is disseminated via social media.

Conclusion

We identified credible messengers, feasible strategies, and elements of impactful messages for interventions to increase adolescent HPV vaccination for U.S. Vietnamese.

Innovation

We focus on a high-risk, underserved population and integrate mixed-methods design and analysis.

Immunogenicity of a quadrivalent human papillomavirus vaccine in pediatric kidney and liver transplant recipients

BACKGROUND

Solid-organ transplant recipients are at increased risk of developing human papillomavirus-related diseases.

METHODS

To evaluate the immunogenicity of a quadrivalent vaccine, a prospective observational study included females aged 12-19 years who had received kidney or liver transplants, or were otherwise healthy volunteers. With the three-dose vaccination, serum antibodies were measured.

RESULTS

The study included 17 transplant recipients (seven kidney and 10 liver) and 16 healthy participants. Six of seven kidney transplant recipients were on three immunosuppressive medications, whereas 9 of the 10 liver transplant recipients were on one. For the serology within 6 months from the last vaccine dose, the geometric mean titers of human papillomavirus types 6, 11, 16, and 18 were 26.7, 8.6, 35.7, and 42.4 (kidney transplant); 579.2, 569.3, 3097.3, and 835.7 (liver transplant); and 860.5, 638.8, 4391.6, and 902.6 milli-Merck Units/ml (healthy). The seropositivity rates of kidney transplant recipients for the four serotypes ranged from 50% to 75%, while all liver transplant recipients and healthy participants had 100% seropositivity rates for all four types. While there were no statistical differences of titers between liver transplant recipients and healthy participants, the titers of kidney transplant recipients were lower than those of healthy participants for type 6 (p = .034), type 11 (p = .032), and type 16 (p = .032).

CONCLUSIONS

The results support the recommendation of human papillomavirus vaccination in pediatric transplant recipients given the significant risk of human papillomavirus-related diseases in this population, though immunogenicity was lower in kidney transplant recipients on multiple immunosuppressive medications.

An Update on Human Papilloma Virus Vaccines: History, Types, Protection, and Efficacy

Human papillomavirus (HPV) is the most common sexually transmitted agent worldwide. Early prevention with HPV vaccination is a safe and effective method against this disease. HPV vaccines provided more protection against several oncogenic HPV strains. Three prophylactic HPV vaccines have been approved to target high-risk HPV types and protect against HPV-related disorders. These existing vaccines are based on the recombinant DNA technology and purified L1 protein that is assembled to form HPV empty shells. The prophylactic vaccines are highly immunogenic and can induce production of specific neutralizing antibodies. However, therapeutic vaccines are different from these prophylactic vaccines. They induced cell-mediated immunity against transformed cells, instead of neutralizing antibodies. The second generation of prophylactic HPV vaccines, made from alternative viral components using cost-effective production strategies, is undergoing clinical evaluation. The purpose of this review is to provide a complete and up-to-date review of the types of HPV vaccines and the efficiency of each of them for readers.

Long-Term Effects of Human Papillomavirus Vaccination in Clinical Trials and Real-World Data: A Systematic Review

The preventive effect of HPV vaccines against anogenital and oropharyngeal cancers has been proven in both clinical trials and real-world data. We reviewed the published evidence about the long-term efficacy and effectiveness of the HPV vaccine in available papers of clinical trials and real-world data. As far as we searched, the longest period of preventive effect for the bivalent, 4-valent, and 9-valent vaccine were 11 years in the Costa Rica trial, 14 years in the FUTURE II, and 8 years in the LTFU extension study of V503-002 and the Scandinavian study, respectively. The sustained clinical effect during the observation period was longest for the 4-valent vaccine. In real-world data, the longest observation period of the vaccine effectiveness was 12 years in an Australian study for the 4-valent vaccine. On the other hand, the longest period of long-term persistence of HPV vaccine-induced seropositivity was 14 years in FUTURE II for the 4-valent vaccine. For the bivalent vaccine, additional long-term follow-up studies may not have been planned due to the launch of the 4-valent and 9-valent vaccines. In some studies of the 9-valent vaccine, the results have not yet been published because of the short observation period. The additional results are expected in the future. In a national immunization program, most girls and boys are inoculated with HPV vaccine by the time puberty begins; thus, it is important to monitor the vaccine effect at least until the sexually active period in their 20s and 30s.

Mechanisms of cellular and humoral immunity through the lens of VLP-based vaccines

INTRODUCTION

Vaccination can be effective defense against many infectious agents and the corresponding diseases. Discoveries elucidating the mechanisms of the immune system have given hopes to developing vaccines against diseases recalcitrant to current treatment/prevention strategies. One such finding is the ability of immunogenic biological nanoparticles to powerfully boost the immunogenicity of poorer antigens conjugated to them with virus-like particle (VLP)-based vaccines as a key example. VLPs take advantage of the well-defined molecular structures associated with sub-unit vaccines and the immunostimulatory nature of conjugate vaccines.

AREAS COVERED

In this review, we will discuss how advances in understanding the immune system can inform VLP-based vaccine design and how VLP-based vaccines have uncovered underlying mechanisms in the immune system.

EXPERT OPINION

As our understanding of mechanisms underlying the immune system increases, that knowledge should inform our vaccine design. Testing of proof-of-concept vaccines in the lab should seek to elucidate the underlying mechanisms of immune responses. The integration of these approaches will allow for VLP-based vaccines to live up to their promise as a powerful plug-and-play platform for next generation vaccine development.

U.S. Vietnamese parents' HPV vaccine decision-making for their adolescents: an exploration of practice-, provider-, and patient-level influences

U.S. Vietnamese have high cervical cancer incidence and low human papillomavirus (HPV) vaccine initiation. Using the P3 model, we explored practice-, provider-, and patient-level determinants of U.S. Vietnamese parents’ HPV vaccine decision-making for their adolescents. We conducted a cross-sectional, online survey (04/2020–12/2020) with U.S. Vietnamese parents who had ≥ 1 adolescent ages 9–18. We assessed HPV vaccination outcomes (initiation, willingness to initiate, completion) and provider recommendation. Modified Poisson regressions were used to identify practice-, provider- and patient-level correlates of outcomes. The sample (n = 408) was 44 years old on average; 83% were female and 85% had a Bachelor’s degree. Around half of adolescents were female (51%) and 13–18 year old (54%). Only 41 and 23% of parents had initiated and completed the HPV vaccine series for their child, respectively. Initiation was associated with receiving provider recommendation (either low- or high-quality), while willingness to initiate was associated with receiving high-quality recommendation. Both initiation and willingness to initiate was negatively associated with parental perception that their child was too young for a “sexually transmitted infection (STI)-preventing vaccine.” Provider recommendation was associated with higher parental U.S. acculturation and the child being older and female. Provider-facing interventions should promote high-quality, age-based, gender-neutral HPV vaccine recommendation. These and population- and individual-facing interventions should recognize the need for additional parental education, particularly related to misconceptions regarding STI prevention.

Prevention and Screening of HPV Malignancies

It is estimated that 5% of the global cancer burden, or approximately 690,000 cancer cases annually, is attributable to human papillomavirus (HPV). Primary prevention through prophylactic vaccination is the best option for reducing the burden of HPV-related cancers. Most high-income countries (HICs) have introduced the HPV vaccine and are routinely vaccinating adolescent boys and girls. Unfortunately, although they suffer the greatest morbidity and mortality due to HPV-related cancers, many lower- and middle-income countries (LMICs) have been unable to initiate and sustain vaccination programs. Secondary prevention in the form of screening has led to substantial declines in cervical cancer incidence in areas with established screening programs, but LMICs with absent or inadequate screening programs have high incidence rates. Meanwhile, HICs have seen incidence rates of anal and oropharyngeal cancers rise owing to the limited availability of organized screening for anal cancer and no validated screening options for oropharyngeal cancer. The implementation of screening programs for individuals at high risk of these cancers has the potential to reduce the burden of cervical cancer in LMICs, of anal and oropharyngeal cancers in HICs, and of anal cancer for highly selected HIV+ populations in LMICs. This review will discuss primary prevention of HPV-related cancers through vaccination and secondary prevention through screening of cervical, anal, and oropharyngeal cancers. Areas of concern and highlights of successes already achieved are included.

Sustainability of neutralising antibodies induced by bivalent or quadrivalent HPV vaccines and correlation with efficacy: a combined follow-up analysis of data from two randomised, double-blind, multicentre, phase 3 trials

BACKGROUND

Quadrivalent and bivalent vaccines against oncogenic human papillomavirus (HPV) are used worldwide with different reported overall efficacies against HPV infections. Although protective concentrations of vaccine-induced antibodies are still not formally defined, we evaluated the sustainability of neutralising antibodies in vaccine trial participants 2-12 years after vaccination and the correlation with reported vaccine efficacy.

METHODS

We did a follow-up analysis of data from the Finnish cohorts of two international, randomised, double-blind, phase 3 trials of HPV vaccines, PATRICIA (bivalent, HPV16 and 18) and FUTURE II (quadrivalent, HPV6, 11, 16, and 18). In 2002 and 2004-05, respectively, Finnish girls aged 16-17 years participated in one of these two trials and consented to health registry follow-up with the Finnish Cancer Registry. The cohorts were also linked with the Finnish Maternity Cohort (FMC) that collects first-trimester serum samples from nearly all pregnant Finnish women, resulting in 2046 post-vaccination serum samples obtained during up to 12 years of follow-up. We obtained serum samples from the FMC-based follow-up of the FUTURE II trial (from the quadrivalent vaccine recipients) and the PATRICIA trial (from corresponding bivalent vaccine recipients who were aligned by follow-up time, and matched by the number of pregnancies). We assessed neutralising antibody concentrations (type-specific seroprevalence) to HPV6, 16, and 18, and cross-neutralising antibody responses to non-vaccine HPV types 31, 33, 45, 52, and 58 from 2 to 12 years after vaccination.

FINDINGS

Up to Dec 31, 2016, we obtained and analysed 577 serum samples from the quadrivalent vaccine recipients and 568 from the bivalent vaccine recipients. In 681 first-pregnancy serum samples, neutralising antibodies to HPV6, 16, and 18 were generally found up to 12 years after vaccination. However, 51 (15%) of 339 quadrivalent vaccine recipients had no detectable HPV18 neutralising antibodies 2-12 years after vaccination, whereas all 342 corresponding bivalent vaccine recipients had HPV18 neutralising antibodies.. In seropositive quadrivalent vaccine recipients, HPV16 geometric mean titres (GMT) halved by years 5-7 (GMT 3679, 95% CI 2377 to 4708) compared with years 2-4 (6642, 2371 to 13 717). Between 5 and 12 years after vaccination, GMT of neutralising antibodies to HPV16 and 18 were 5·7 times and 12·4 times higher, respectively, in seropositive bivalent vaccine recipients than in the quadrivalent vaccine recipients. Cross-neutralising antibodies to HPV31, 33, 45, 52, and 58 were more prevalent in the bivalent vaccine recipients but, when measurable, sustainable up to 12 years after vaccination with similar GMTs in both vaccine cohorts. Seroprevalence for HPV16, 31, 33, 52, and 58 significantly correlated with vaccine efficacy against persistent HPV infections in the bivalent vaccine recipients only (r_s=0·90, 95% CI 0·09 to 0·99, p=0·037, compared with r_s=0·62, 95% CI -0·58 to 0·97, p=0·27 for the quadrivalent vaccine recipients). Correlation of protection with prevalence of neutralising or cross-neutralising HPV antibodies was not significant in the quadrivalent vaccine recipients.

INTERPRETATION

The observed significant differences in the immunogenicity of the two vaccines are in line with the differences in their cross-protective efficacy. Protective HPV vaccine-induced antibody titres can be detected up to 12 years after vaccination.

FUNDING

Academy of Finland and Finnish Cancer Foundation.

Vaccine effectiveness following routine immunization with bivalent HPV vaccine: Protection against incident genital HPV infections from a reduced-dosing schedule

Background

In the Netherlands, the bivalent human papillomavirus (HPV) vaccine has been offered to preadolescent girls via the National Immunization Program in a 2-dose schedule since 2014. The current study estimates vaccine effectiveness (VE) against HPV infections up to 4 years postvaccination among girls eligible for routine 2-dose immunization.

Methods

A cohort study (HAVANA2) was used in which participants annually filled out an online questionnaire and provided a vaginal self-sample for determination of HPV by the SPF10-LiPA25 assay, able to detect 25 HPV types. VE against incident type-specific infections and pooled outcomes was estimated by a Cox proportional hazards model with shared frailty between the HPV types.

Results

In total, 2027 girls were included in the study, 1098 (54.2%) of whom were vaccinated with 2 doses. Highest incidence rate was 5.0/1000 person-years (HPV-51) among vaccinated participants and 9.1/1000 person-years (HPV-74) among unvaccinated participants. Adjusted pooled VE was 84.0% (95% confidence interval [CI], 27.0%–96.5%) against incident HPV-16/18 infections and 86.5% (95% CI, 39.5%–97.08%) against cross-protective types HPV-31/33/45.

Conclusions

Four years postvaccination, 2 doses of bivalent HPV vaccine were effective in the prevention of incident HPV-16/18 infections and provided cross-protection to HPV-31/33/45. Our VE estimates rival those from 3-dose schedules, indicating comparable protection by 2-dose schedules.

National genotype prevalence and age distribution of human papillomavirus from infection to cervical cancer in Japanese women: a systematic review and meta-analysis protocol

BACKGROUND

Despite prophylactic human papillomavirus (HPV) vaccination being a safe, effective and cost-effective public health intervention for the prevention of cervical cancer, the HPV vaccine is not actively recommended or promoted by the Ministry of Health Labour and Welfare in Japan. With already very low levels of cervical screening below 30%, and vaccination levels that are below levels that award any population effect at 0.3% of the eligible population, cervical cancer mortality is higher than other similar high-income countries at 4.4/100,000 (2900) deaths per year in 2015. There is limited population-based or nationally representative data for HPV genotype distribution in Japan, thus making an assessment of the burden of vaccine-preventable cervical cancer difficult. Therefore, this systematic review and meta-analysis aims to determine the HPV genotype prevalence and age distribution of HPV infection in women with a cytological or histological diagnosis of normal through cervical cancer in Japan. We anticipate this information will guide and enhance programme interventions to reduce vaccine-preventable cervical cancer mortality in Japan.

METHODS

PubMed, Embase and the Japan Medical Abstract Society Database will be searched from the date of establishment to March 2021 to identify original research articles that report the prevalence of HPV genotypes in Japanese women with normal cervical cytology, low grade, high grade and cancerous cervical lesions. No exclusion criteria relating to language or publication date will be applied. The quality of the studies will be assessed using the Joanna Briggs checklist for prevalence studies. Randomised control trials, cohort studies, cross-sectional and prevalence studies will be considered eligible. Study findings will be combined using a traditional random-effects or fixed-effects meta-analysis to summarise pooled prevalence and 95% confidence intervals depending on heterogeneity. Subgroup analyses and meta-regression will be used to investigate heterogeneity, and sensitivity analyses will be conducted to assess the robustness of the findings.

DISCUSSION

To our knowledge, this is the first systematic review protocol that includes both Japanese and English peer-reviewed articles for the determination of genotype-specific HPV prevalence in cytological or histological confirmed normal cervical specimens, low- and high-grade intraepithelial lesions and cervical cancers by age in Japan. We anticipate this information will guide and enhance programme interventions to reduce vaccine-preventable cervical cancer mortality in Japan.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018117596.

Current and future vaccine clinical research with the licensed 2-, 4-, and 9-valent VLP HPV vaccines: What's ongoing, what's needed?

Prophylactic HPV vaccination has been a great public health success. For >20 years, clinical trials were conducted with the 2-, 4-, and/or 9-valent vaccines in young-adult females, mid-adult women, males, and adolescents. In all studies, the vaccines were highly efficacious, immunogenic, and well tolerated. Following vaccine licensure and utilization in national vaccine programs globally (real-world settings primarily in high income countries), numerous studies demonstrated that the vaccines continue to have an excellent safety profile and have dramatically reduced the incidence of genital warts, HPV vaccine-type prevalence, and precancerous lesions. Thirty-eight clinical trials with the currently licensed HPV vaccines are ongoing. Key questions being addressed in new trials include: efficacy against persistent infection and immunogenicity of a 1-dose regimen; efficacy of 3 doses in 20-45-year-old females; use in postpartum women and immunocompromised individuals (HIV, liver and kidney transplants); dose sparing via intradermal administration; use in combination with a PD1 monoclonal antibody in patients with cervical cancer; impact on recurrent disease in women undergoing cervical conization; persistence of protection; and use to prevent oropharyngeal cancer. Additional clinical research that should be conducted includes: long-term follow-up, particularly of 1- and 2-dose regimens; further evaluation of flexible 2-dose regimens; immunogenicity of 1- or 2-dose regimens in persons ≥15 years old and immunocompromised populations; safety and immunogenicity of 1 or 2 doses in children <9 years old; assessment of the vaccine in the prevention of transmission; interchangeability with newer HPV vaccines; additional concomitant use studies; and prevention of penile cancer and recurrent respiratory papillomatosis.

A guide to vaccinology: from basic principles to new developments

Immunization is a cornerstone of public health policy and is demonstrably highly cost-effective when used to protect child health. Although it could be argued that immunology has not thus far contributed much to vaccine development, in that most of the vaccines we use today were developed and tested empirically, it is clear that there are major challenges ahead to develop new vaccines for difficult-to-target pathogens, for which we urgently need a better understanding of protective immunity. Moreover, recognition of the huge potential and challenges for vaccines to control disease outbreaks and protect the older population, together with the availability of an array of new technologies, make it the perfect time for immunologists to be involved in designing the next generation of powerful immunogens. This Review provides an introductory overview of vaccines, immunization and related issues and thereby aims to inform a broad scientific audience about the underlying immunological concepts.

This Review, aimed at a broad scientific audience, provides an introductory guide to the history, development and immunological basis of vaccines, immunization and related issues to provide insight into the challenges facing immunologists who are designing the next generation of vaccines.

Optimized dose of synthetic analogues of Monophosphoryl lipid A as an effective alternative for formulating recombinant human papillomavirus vaccine

Adjuvants are a crucial component of recombinant vaccines such as the human papillomavirus (HPV) vaccine. Monophosphoryl lipid A (MPL) extracted from Salmonella Minnesota lipopolysaccharide is used as an adjuvant for the HPV vaccine. Due to the limitations in accessibility and reproducibility of MPL, investigating synthetic analogues of MPL (synMPL) is urgently needed to overcome these limitations. In this study, female BALB/c mice were vaccinated by HPV vaccine formulated with synMPL and aluminum hydroxide gel in which the concentration of synMPL ranged from 0 to 100 μg/dose. Anti-HPV L1 VLP antibody was measured for each group through Indirect ELISA and compared with Cervarix and Gardasil vaccines as approved anti-HPV vaccines. SynMPL showed a concentration-dependent increase up to 50 μg/dose in the immunogenicity of the vaccine. Therefore, synMPL at concentration of 50 μg/dose was selected as optimum concentration. The GMT profiling of synMPL-formulated vaccine (named Papilloguard) and Cervarix was not statistically different (Mann-Whitney test). The Gardasil vaccine showed 10-fold lower GMT for anti-HPV 18 L1 VLP antibody but anti-HPV 16 L1 VLP antibody was similar to Cervarix and Papilloguard. The current findings suggest that the synMPL in combination with aluminum hydroxide could be used as a potential adjuvant candidate for human vaccine.

Sex, Age, and Race Effects on Immunogenicity of MenB-FHbp, A Bivalent Meningococcal B Vaccine: Pooled Evaluation of Clinical Trial Data

Introduction

An extensive clinical development program showed that the meningococcal serogroup B-factor H binding protein (MenB-FHbp) vaccine affords protection against MenB disease for adolescents and adults. Data were pooled from multiple studies within the program to examine whether MenB-FHbp immunogenicity was influenced by sex, age, or race.

Methods

Immunogenicity was assessed in subjects from seven studies who received 120 µg MenB-FHbp (at 0, 2, 6 months) and had evaluated immune responses against four representative test strains via serum bactericidal assays using human complement (hSBAs). Immune responses were presented by sex (male, female), age group (10–14, 15–18, 19–25, 10–25 years), and race (white, black, Asian, other).

Results

Among 8026 subjects aged 10–25 years included in this analysis, MenB-FHbp elicited robust immune responses in a high percentage of subjects regardless of demographic characteristics. Across all test strains and demographic subsets, a ≥ 4-fold rise in titer from baseline was achieved in 76.7–95.0% of subjects, with no major differences by sex, age groups assessed, or races evaluated. Corresponding percentages achieving titers ≥ the lower limit of quantification (LLOQ) against all four strains combined were 79.7–87.3% (sex), 81.6–85.5% (age), and 80.0–88.1% (race). Minor differences were observed for geometric mean titers and percentages of subjects achieving titers ≥ LLOQ against each strain based on demographics.

Conclusion

These data suggested no clinically meaningful differences in MenB-FHbp immunogenicity when administered as a three-dose schedule based on sex, ages assessed, or races evaluated. This analysis supports the continued recommended use of MenB-FHbp to prevent MenB disease in adolescents and young adults.

Trial Registration

ClinicalTrials.gov identifiers, NCT00808028, NCT01830855, NCT01323270, NCT01461993, NCT01461980, NCT01352845, and NCT01299480.

Immunogenicity of an Escherichia coli-produced bivalent human papillomavirus vaccine under different vaccination intervals

A new Escherichia coli-produced human papillomavirus (HPV)-16/18 vaccine has been shown to be safe and highly efficacious and was recently licensed in China. As a post hoc analysis of the phase III trial, this study aimed to assess the impact of vaccination time deviations on the specific antibody response and guide the better usage of this vaccine in the real world. A total of 3689 healthy women aged 18-45 years old were randomly assigned to receive the bivalent HPV-16/18 vaccine according to a 0-, 1- and 6-month schedule with a wide vaccination interval. The first vaccination interval between the 1st and 2nd doses (the 1st interval) was divided into three groups: 28-40 d, 41-50 d and 51-60 d. The second vaccination interval between the 2nd and 3rd doses (the 2nd interval) was divided into three groups: 103-139 d, 140-160 d and 161-198 d. The reverse cumulative curves for the IgG of the three groups with different 1st vaccination intervals or with different 2nd vaccination intervals at month 7 almost overlapped for both HPV-16 and HPV-18. Compared with the standard vaccination schedule (a 1st interval of 28-40 d and a 2nd interval of 140-160 d) subgroup, all the subgroups had GMC ratios greater than 0.83, with the lower limit of 95% CIs higher than 0.64. In conclusion, a slight deviation in the vaccination time of the 2nd and 3rd doses has only a minor, insignificant impact on the immune response induced by the Escherichia coli-produced HPV-16/18 vaccine.

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

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

An educational intervention to improve attitudes regarding HPV vaccination and comfort with counseling among US medical students

Many medical students are not comfortable recommending the human papillomavirus (HPV) vaccine because they do not feel prepared to discuss it with their patients. A prior study demonstrated that this is particularly a problem among unvaccinated students. Our purpose was to determine if medical student attitudes and comfort with counseling could be improved by attending a single lecture delivered by an expert on the topic. To assess the effects of the educational program, we conducted pre- and posttests on medical students before and after a single lecture on HPV vaccination. Changes in items related to attitude and comfort were examined. Student characteristics associated with changes in scores were also examined and compared. A total of 256 medical students participated in the pre- and posttests. Before the lecture, students demonstrated low knowledge of HPV vaccination and did not feel comfortable counseling parents of younger patients. However, students <30 years of age demonstrated significant improvements after the lecture in comfort. Asian and Hispanic students showed the greatest improvement in comfort with counseling, as did students who reported they had not received the HPV vaccine. Attending a single lecture given by an expert can improve medical students' attitudes and comfort with HPV vaccine counseling, especially if the students were not vaccinated themselves. This study suggests that including material on HPV vaccination in the standard medical student curriculum could help increase physician recommendation for the HPV vaccine.

The Use of Both Therapeutic and Prophylactic Vaccines in the Therapy of Papillomavirus Disease

Human papillomavirus (HPV) is the most common sexually transmitted virus. The high-risk HPV types (i.e., HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59) are considered to be the main etiological agents of genital tract cancers, such as cervical, vulvar, vaginal, penile, and anal cancers, and of a subset of head and neck cancers. Three prophylactic HPV vaccines are available that are bivalent (vs. HPV16, 18), tetravalent (vs. HPV6, 11, 16, 18), and non-avalent (vs. HPV6, 11, 16, 18, 31, 33,45, 52, 58). All of these vaccines are based on recombinant DNA technology, and they are prepared from the purified L1 protein that self-assembles to form the HPV type-specific empty shells (i.e., virus-like particles). These vaccines are highly immunogenic and induce specific antibodies. Therapeutic vaccines differ from prophylactic vaccines, as they are designed to generate cell-mediated immunity against transformed cells, rather than neutralizing antibodies. Among the HPV proteins, the E6 and E7 oncoproteins are considered almost ideal as targets for immunotherapy of cervical cancer, as they are essential for the onset and evolution of malignancy and are constitutively expressed in both premalignant and invasive lesions. Several strategies have been investigated for HPV therapeutic vaccines designed to enhance CD4⁺ and CD8⁺ T-cell responses, including genetic vaccines (i.e., DNA/ RNA/virus/ bacterial), and protein-based, peptide-based or dendritic-cell-based vaccines. However, no vaccine has yet been licensed for therapeutic use. Several studies have suggested that administration of prophylactic vaccines immediately after surgical treatment of CIN2 cervical lesions can be considered as an adjuvant to prevent reactivation or reinfection, and other studies have described the relevance of prophylactic vaccines in the management of genital warts. This review summarizes the leading features of therapeutic vaccines, which mainly target the early oncoproteins E6 and E7, and prophylactic vaccines, which are based on the L1 capsid protein. Through an analysis of the specific immunogenic properties of these two types of vaccines, we discuss why and how prophylactic vaccines can be effective in the treatment of HPV-related lesions and relapse.

Selective Persistence of HPV Cross-Neutralising Antibodies following Reduced-Dose HPV Vaccine Schedules

The duration of cross-neutralising antibody responses (cross-NAb) following HPV immunisation is unknown. We compared cross-NAb responses in cohort of girls who were either unimmunised or had received immunisation with one, two or three doses of 4vHPV (Gardasil^®, Merck Inc., Kenilworth, NJ, USA) six years earlier, before and one month after a booster dose of 2vHPV (Cervarix^®, GSK, Brentford, UK). NAb to potentially cross-reactive HPV genotypes 31, 33, 45, 52 and 58 were measured using a HPV pseudovirion-based neutralisation assay. Girls who had previously received at least one dose of 4vHPV had significantly higher NAb titres for HPV31 when compared with unimmunised girls, whereas no difference in NAb titre was observed for four other genotypes (33, 45, 52 and 58). Following a single further immunisation with 2vHPV, NAb titres to each of the five tested HPV genotypes were comparable for girls who previously received one, two or three doses of 4vHPV, and were significantly higher than for previously unimmunised girls. Immunisation with one, two or three doses of 4vHPV induced NAb to HPV31 that persisted for six years, but there was no persistence of NAb to HPV33, 45, 52 or 58. Our results suggest that one or two doses of 4vHPV may provide long-term protection against HPV31.

Lot-to-lot consistency study of an Escherichia coli-produced bivalent human papillomavirus vaccine in adult women: a randomized trial

An Escherichia. coli-produced HPV-16/18 bivalent vaccine has been proved to be well-tolerated and highly efficacious against diseases associated with vaccine HPV types. As a part of the multi-center, randomized, double-blind phase III clinical trial, this lot-to-lot consistency study aimed to assess the safety and immunogenicity consistency of this novel HPV vaccine, which is also one of the objectives of the phase III trial. A total of 3689 healthy women aged 18-45 years were enrolled and randomly assigned 1:1:1 to three lots of the HPV vaccine groups. The primary outcomes were the IgG antibody level at 1 month after the last dose (month 7). In the immunogenicity per-protocol set (PPS), almost all of the participants seroconverted at month 7 and remained seropositive at month 42. For each paired comparison of the three lot groups, the two-sides of 90% CIs of GMC ratios for both IgG and neutralizing antibodies for HPV-16 and HPV-18 at month 7 were within the equivalence interval [0.5, 2]. Lot consistency was also demonstrated at month 42. The majority of recorded solicited reactions were mild or moderate. The incidences of solicited reactions of Lot 2 and Lot 3 were slightly higher than Lot 1. However, the incidences of solicited reactions of ≥ grade 3 and solicited reactions by symptoms were all similar among the three lot groups. None of the SAEs was considered related to vaccination by the investigator. In conclusion, this study demonstrates lot-to-lot consistency of the 3 consecutive lots of the E. coli-produced HPV-16/18 bivalent vaccine.

Long-term Antibody Response to Human Papillomavirus Vaccines: Up to 12 Years of Follow-up in the Finnish Maternity Cohort

Background

Most cervical cancers are caused by vaccine-preventable infections with human papillomaviruses (HPV). The HPV prophylactic vaccines Gardasil and Cervarix have been widely used for >10 years and are reported to induce high antibody levels. A head-to-head comparison of the antibody responses induced by the 2 vaccines has been performed only up to 5 years.

Methods

Among 3300 Finnish females aged 16-17 years who got 1 of the 2 HPV vaccines in phase 3 licensure trials, virtually all consented to registry-based long-term follow-up. Linkage with the Finnish Maternity Cohort found that they donated >2500 serum samples up to 12 years later. Sera of 337 (38.6%) Gardasil and 730 (30.3%) Cervarix vaccine recipients were retrieved from the Finnish Maternity Cohort biobank and type-specific anti-HPV antibody levels were determined using in-house multiplexed heparin-HPV pseudovirion Luminex assay.

Results

Anti-HPV-16 and anti-HPV-18 antibody levels remained stable and above natural infection-related antibody levels for up to 12 years for most vaccine recipients. The median antibody levels were higher among Cervarix recipients 7-12 years post vaccination (P < .0001).

Conclusions

The stability of vaccine-induced antibody levels is in accordance with the high long-term protection reported previously. The differences in antibody levels induced by the 2 vaccines imply that continued follow-up to identify possible breakthrough cases and estimation of the minimal protective levels of serum antibodies is a research priority.

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

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

Immunogenicity noninferiority study of 2 doses and 3 doses of an Escherichia coli-produced HPV bivalent vaccine in girls vs. 3 doses in young women

A new HPV-16/18 bivalent vaccine expressed by the Escherichia coli has been proven to be efficacious in adult women. A randomized, immunogenicity noninferiority study of this candidate vaccine was conducted in December 2015 in China. Girls aged 9–14 years were randomized to receive 2 doses at months 0 and 6 (n=301) or 3 doses at months 0, 1 and 6 (n=304). Girls aged 15–17 years (n=149) and women aged 18–26 years (n=225) received 3 doses. The objectives included noninferiority analysis of the IgG geometric mean concentration (GMC) ratio (95% CI, lower bound>0.5) to HPV-16 and HPV-18 at month 7 in girls compared with women. In the per-protocol set, the GMC ratio of IgG was noninferior for girls aged 9–17 years receiving 3 doses compared with women (1.76 (95% CI, 1.56, 1.99) for HPV-16 and 1.93 (95% CI, 1.69, 2.21) for HPV-18) and noninferior for girls aged 9–14 years receiving 2 doses compared with women (1.45 (95% CI, 1.25, 1.62) for HPV-16 and 1.17 (95% CI, 1.02, 1.33) for HPV-18). Noninferiority was also demonstrated for neutralizing antibodies. The immunogenicity of the HPV vaccine in girls receiving 3 or 2 doses was noninferior compared with that in young adult women.

Adolescent providers' knowledge of human papillomavirus vaccination age guidelines in five countries

Purpose: To examine provider knowledge of HPV vaccination age guidelines in five countries. Methods: A total of 151 providers of adolescent vaccinations in Argentina, Malaysia, South Africa, South Korea, and Spain were interviewed between October 2013 and April 2014. Univariate analyses compared providers' understanding of recommended age groups for HPV vaccination to that of each country's national guidelines. Results: In three of five countries surveyed, most providers (97% South Africa, 95% Argentina, 87% Malaysia) included all nationally recommended ages in their target age group. However, a relatively large proportion of vaccinators in some countries (83% Malaysia, 55% Argentina) believed that HPV vaccination was recommended for women above age 26, far exceeding national guidelines, and beyond the maximum recommended age in the United States. National median minimum and maximum age recommendations cited by the respondents for HPV vaccination were 11 and 29 years in Argentina (national guideline: 11-14), 13 and 48 years in Malaysia (guideline 13-14), 8 and 14 years in South Africa (guideline 9-14), 10 and 20 years in South Korea (guideline 11-14), and 11 and 12 years in Spain (guideline 11-14). In all countries, a higher percentage of vaccinators included all nationally recommended ages for vaccination, as compared to providers who did not administer HPV vaccination. Conclusions: Overall, a substantial proportion of providers incorrectly reported their country's age guidelines for HPV vaccination, particularly the upper age limit. As provider recommendation is among the strongest predictors of successful vaccination uptake among adolescents, improved education and clarification of national guidelines for providers administering HPV vaccination is essential to optimize prevention of infection and associated disease.

HPV Vaccine: Updates and Highlights

HPV is the most common sexually transmitted biological agent and is the cause of many conditions in men and women, including precancer lesions and cancer. Three prophylactic HPV vaccines targeting high-risk HPV types are available in many countries worldwide: 2-, 4- and 9-valent vaccines. All the 3 vaccines use recombinant DNA technology and are prepared from the purified L1 protein that self-assembles to form HPV type-specific empty shells. This non-systematic review aims to summarize the HPV epidemiology and the vaccine development to review the landmark trials of HPV vaccine, to present to most remarkable results from clinical trials and the real world, and to stress the challenges and the barriers for HPV vaccine implementation.

Persistence of immune response following bivalent HPV vaccination: A follow-up study among girls routinely vaccinated with a two-dose schedule

BACKGROUND

In this cohort study, we examined antibody levels and avidity after a two-dose schedule (0, 6 months) of the bivalent HPV-vaccine in girls routinely vaccinated in the Dutch HPV-vaccination program, up to 2 years following vaccination.

METHODS

A blood sample at 7, 12 and 24 months after the first dose and questionnaire data were collected (n = 56). HPV type-specific antibody concentrations (lU/ml) against seven types (HPV16/18/31/33/45/52/58) were assessed using a validated virus-like particles (VLP) multiplex immunoassay. Avidity was tested using a modification of this assay.

RESULTS

Seropositivity for vaccine types HPV 16 and 18 was 100% up to month 24, but declined for HPV-types 31/33/45/52/58, although not statistically significant for HPV45. All Geometric Mean Concentrations (GMCs) declined by months 12 and 24, but remained high for HPV16/18. Between month 7 and 12, GMCs declined more for other types. High avidity antibodies were induced up to 24 months for vaccine types (75%, 76-78% and 81-82% at months 7, 12 and 24, respectively), but for other types antibody avidity was 16-29% at month 7, 20-32% at month 12 and 19-32% at month 24.

CONCLUSIONS

GMCs declined over time for HPV-types 16/18/31/33/45/52/58, but remained high for vaccine-types HPV16/18 up to 24 months of follow-up. Antibody avidity was >75% for vaccine types but <35% for other HPV-types. Further follow-up of this cohort will provide insight into antibody and avidity kinetics over time.

The effect of exercise on local and systemic adverse reactions after vaccinations - Outcomes of two randomized controlled trials

INTRODUCTION

An adverse reaction associated with vaccination is considered to be a key barrier to vaccinate, yet little attention has been given to interventions to reduce their occurrence. Exercise is a behavioural adjuvant which may also influence adverse reactions. Here, two randomized controlled trials are reported, examining the effects of exercise on self-reported adverse reactions following vaccination in adolescents and young adults.

METHODS

Study one; 116 adolescents receiving the HPV vaccine were randomly allocated to either Control (n = 56) or Pre-vaccine Exercise (n = 60) group (2015-2016). Exercise consisted of 15-minutes upper body exercise. Study two; 78 young adults receiving the influenza vaccine were randomly allocated to either Control (n = 19), or one of 3 exercise groups: Pre-vaccine Arm (n = 19), Pre-vaccine Leg (n = 20) or Post-vaccine Arm (n = 20) (2017). Exercise included 15-minutes of arm or leg exercises prior to or after vaccination. All participants in both studies completed an adverse events diary for seven-days post-vaccination.

RESULTS

Study one; Reported days of tenderness in female adolescents that exercised were significantly lower than control (p = 0.032), with a similar trend in reported days of pain (p = 0.050). Furthermore, days of feeling ill (p = 0.070) and reduced appetite (p = 0.067) were found to be lower with exercise, although not significant. Overall, female adolescents reported significantly more days of pain (p = 0.003), tenderness (p < 0.001), swelling (p = 0.011), and feeling ill (p = 0.0040). Study two; Exercise groups reported reduced days of swelling (p = 0.018), fever (p = 0.013), and lowered appetite (p = 0.011) across both genders. Furthermore, females reported reduced days of medication use with exercise (p = 0.034), and a trend toward reduced days of swelling (p = 0.052).

DISCUSSION

In two separate trials, a short bout of exercise reduced reported adverse reactions after vaccinations for local and systemic adverse reactions. Gender differences in reported local and systemic adverse reactions were more evident among adolescents than young adults. These findings support the need for further work to examine the potential benefit of exercise in improving vaccination procedures.

Are two doses of human papillomavirus vaccine sufficient for girls aged 15-18 years? Results from a cohort study in India

Extending two-dose recommendations of HPV vaccine to girls between 15 and 18 years will reduce program cost and improve compliance. Immunogenicity and vaccine targeted HPV infection outcomes were compared between 1795 girls aged 15-18 years receiving two (1-180 days) and 1515 girls of same age receiving three (1-60-180 days) doses. Immunogenicity outcomes in 15-18 year old two-dose recipients were also compared with the 10-14 year old three-dose (N = 2833) and two-dose (N = 3184) recipients. The 15-18 year old two-dose recipients had non-inferior L1-binding antibody titres at seven months against vaccine-targeted HPV types compared to three-dose recipients at 15-18 years and three-dose recipients at 10-14 years of age. Neutralizing antibody titres at 18 months in 15-18 year old two-dose recipients were non-inferior to same age three-dose recipients for all except HPV 18. The titres were inferior to those in the 10-14 year old three-dose recipients for all targeted types. Frequency of incident infections from vaccine-targeted HPV types in the 15-18 year old two-dose recipients was similar to the three dose recipients. None of the girls receiving two or three doses had persistent infection from vaccine-targeted types. These findings support that two doses of HPV vaccine can be extended to girls aged 15-18 years.

Prophylactic vaccination against human papillomaviruses to prevent cervical cancer and its precursors

BACKGROUND

Persistent infection with high-risk human papillomaviruses (hrHPV) types is causally linked with the development of cervical precancer and cancer. HPV types 16 and 18 cause approximately 70% of cervical cancers worldwide.

OBJECTIVES

To evaluate the harms and protection of prophylactic human papillomaviruses (HPV) vaccines against cervical precancer and HPV16/18 infection in adolescent girls and women.

SEARCH METHODS

We searched MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL) and Embase (June 2017) for reports on effects from trials. We searched trial registries and company results' registers to identify unpublished data for mortality and serious adverse events.

SELECTION CRITERIA

Randomised controlled trials comparing efficacy and safety in females offered HPV vaccines with placebo (vaccine adjuvants or another control vaccine).

DATA COLLECTION AND ANALYSIS

We used Cochrane methodology and GRADE to rate the certainty of evidence for protection against cervical precancer (cervical intraepithelial neoplasia grade 2 and above [CIN2+], CIN grade 3 and above [CIN3+], and adenocarcinoma-in-situ [AIS]), and for harms. We distinguished between the effects of vaccines by participants' baseline HPV DNA status. The outcomes were precancer associated with vaccine HPV types and precancer irrespective of HPV type. Results are presented as risks in control and vaccination groups and risk ratios (RR) with 95% confidence intervals in brackets.

MAIN RESULTS

We included 26 trials (73,428 participants). Ten trials, with follow-up of 1.3 to 8 years, addressed protection against CIN/AIS. Vaccine safety was evaluated over a period of 6 months to 7 years in 23 studies. Studies were not large enough or of sufficient duration to evaluate cervical cancer outcomes. All but one of the trials was funded by the vaccine manufacturers. We judged most included trials to be at low risk of bias. Studies involved monovalent (N = 1), bivalent (N = 18), and quadrivalent vaccines (N = 7). Most women were under 26 years of age. Three trials recruited women aged 25 and over. We summarize the effects of vaccines in participants who had at least one immunisation.Efficacy endpoints by initial HPV DNA statushrHPV negativeHPV vaccines reduce CIN2+, CIN3+, AIS associated with HPV16/18 compared with placebo in adolescent girls and women aged 15 to 26. There is high-certainty evidence that vaccines lower CIN2+ from 164 to 2/10,000 (RR 0.01 (0 to 0.05)) and CIN3+ from 70 to 0/10,000 (RR 0.01 (0.00 to 0.10). There is moderate-certainty evidence that vaccines reduce the risk of AIS from 9 to 0/10,000 (RR 0.10 (0.01 to 0.82).HPV vaccines reduce the risk of any CIN2+ from 287 to 106/10,000 (RR 0.37 (0.25 to 0.55), high certainty) and probably reduce any AIS lesions from 10 to 0/10,000 (RR 0.1 (0.01 to 0.76), moderate certainty). The size of reduction in CIN3+ with vaccines differed between bivalent and quadrivalent vaccines (bivalent: RR 0.08 (0.03 to 0.23), high certainty; quadrivalent: RR 0.54 (0.36 to 0.82), moderate certainty). Data in older women were not available for this comparison.HPV16/18 negativeIn those aged 15 to 26 years, vaccines reduce CIN2+ associated with HPV16/18 from 113 to 6 /10,000 (RR 0.05 (0.03 to 0.10). In women 24 years or older the absolute and relative reduction in the risk of these lesions is smaller (from 45 to 14/10,000, (RR 0.30 (0.11 to 0.81), moderate certainty). HPV vaccines reduce the risk of CIN3+ and AIS associated with HPV16/18 in younger women (RR 0.05 (0.02 to 0.14), high certainty and RR 0.09 (0.01 to 0.72), moderate certainty, respectively). No trials in older women have measured these outcomes.Vaccines reduce any CIN2+ from 231 to 95/10,000, (RR 0.41 (0.32 to 0.52)) in younger women. No data are reported for more severe lesions.Regardless of HPV DNA statusIn younger women HPV vaccines reduce the risk of CIN2+ associated with HPV16/18 from 341 to 157/10,000 (RR 0.46 (0.37 to 0.57), high certainty). Similar reductions in risk were observed for CIN3+ associated with HPV16/18 (high certainty). The number of women with AIS associated with HPV16/18 is reduced from 14 to 5/10,000 with HPV vaccines (high certainty).HPV vaccines reduce any CIN2+ from 559 to 391/10,000 (RR 0.70 (0.58 to 0.85, high certainty) and any AIS from 17 to 5/10,000 (RR 0.32 (0.15 to 0.67), high certainty). The reduction in any CIN3+ differed by vaccine type (bivalent vaccine: RR 0.55 (0.43 to 0.71) and quadrivalent vaccine: RR 0.81 (0.69 to 0.96)).In women vaccinated at 24 to 45 years of age, there is moderate-certainty evidence that the risks of CIN2+ associated with HPV16/18 and any CIN2+ are similar between vaccinated and unvaccinated women (RR 0.74 (0.52 to 1.05) and RR 1.04 (0.83 to 1.30) respectively). No data are reported in this age group for CIN3+ or AIS.Adverse effectsThe risk of serious adverse events is similar between control and HPV vaccines in women of all ages (669 versus 656/10,000, RR 0.98 (0.92 to 1.05), high certainty). Mortality was 11/10,000 in control groups compared with 14/10,000 (9 to 22) with HPV vaccine (RR 1.29 [0.85 to 1.98]; low certainty). The number of deaths was low overall but there is a higher number of deaths in older women. No pattern in the cause or timing of death has been established.Pregnancy outcomesAmong those who became pregnant during the studies, we did not find an increased risk of miscarriage (1618 versus 1424/10,000, RR 0.88 (0.68 to 1.14), high certainty) or termination (931 versus 838/10,000 RR 0.90 (0.80 to 1.02), high certainty). The effects on congenital abnormalities and stillbirths are uncertain (RR 1.22 (0.88 to 1.69), moderate certainty and (RR 1.12 (0.68 to 1.83), moderate certainty, respectively).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that HPV vaccines protect against cervical precancer in adolescent girls and young women aged 15 to 26. The effect is higher for lesions associated with HPV16/18 than for lesions irrespective of HPV type. The effect is greater in those who are negative for hrHPV or HPV16/18 DNA at enrolment than those unselected for HPV DNA status. There is moderate-certainty evidence that HPV vaccines reduce CIN2+ in older women who are HPV16/18 negative, but not when they are unselected by HPV DNA status.We did not find an increased risk of serious adverse effects. Although the number of deaths is low overall, there were more deaths among women older than 25 years who received the vaccine. The deaths reported in the studies have been judged not to be related to the vaccine. Increased risk of adverse pregnancy outcomes after HPV vaccination cannot be excluded, although the risk of miscarriage and termination are similar between trial arms. Long-term of follow-up is needed to monitor the impact on cervical cancer, occurrence of rare harms and pregnancy outcomes.

Safety and Immunogenicity of the HPV-16/18 AS04-adjuvanted Vaccine in 4-6-year-old Girls: Results to Month 12 From a Randomized Trial

BACKGROUND

The burden of cervical cancer caused by human papillomavirus (HPV) is high in Latin America. The suboptimal HPV vaccination coverage in adolescents could be improved by pediatric immunization. HPV vaccination has not yet been reported in girls <9 years of age.

METHODS

This ongoing phase III, controlled, randomized, single-blind, multicenter study conducted in Colombia, Mexico and Panama (NCT01627561) evaluated the safety and immunogenicity of AS04-HPV-16/18 vaccine in 4-6-year-old girls. Healthy girls (randomized 1:1) received either 2 doses of AS04-HPV-16/18 vaccine (HPV group, N=74) or 1 dose of each measles-mumps-rubella and diphtheria-tetanus-acellular-pertussis vaccines (control group, N=74) 6 months apart. We report the safety and serum anti-HPV-16 and anti-HPV-18 antibodies (measured by enzyme-linked immunosorbent assay) up to 6 months postvaccination, that is, month (M) 12.

RESULTS

Injection site pain was the most frequently reported solicited local symptom in HPV vaccinees. The incidence of other solicited and unsolicited symptoms after each vaccination was similar between the HPV and control group. Until M12, 1 girl in the HPV group and 2 in the control group reported serious adverse events; all serious adverse events were assessed as unrelated to study vaccines. No potential immune-mediated diseases were identified. All girls seroconverted for both antigens after 2 doses of AS04-HPV-16/18. In initially seronegative girls, anti-HPV-16 geometric mean concentrations were 20080.0 enzyme-linked immunosorbent assay units (EU)/mL at M7 and 3246.5 EU/mL at M12; anti-HPV-18 geometric mean concentrations were 10621.8 EU/mL at M7 and 1216.6 EU/mL at M12.

CONCLUSIONS

Two-dose vaccination with AS04-HPV-16/18 was well tolerated and induced adequate antibody responses in 4-6-year-old girls.

Simple and Elaborated Clinician Reminder Prompts for Human Papillomavirus Vaccination: A Randomized Clinical Trial

OBJECTIVE

To evaluate the effects of simple and elaborated health care provider (HCP) reminder prompts on human papillomavirus (HPV) vaccine initiation rates.

METHODS

Twenty-nine pediatric HCPs serving 5 pediatric clinics were randomized to 1 of 3 arms: 1) usual practice control, 2) simple reminder prompt, and 3) elaborated reminder prompt, which included suggested language for recommending the early adolescent platform vaccines. Prompts were delivered via a computer-based clinical decision support system deployed in the 5 clinics. Eligible patients were ages 11 to 13 years, had not received HPV vaccine, and were due for meningococcal ACWY (MenACWY) vaccine and/or the tetanus, diphtheria, and pertussis booster (Tdap). Receipt of HPV vaccine was determined via automated queries sent to the Indiana immunization registry. Data were analyzed via logistic regression models, with generalized estimating equations used to account for the clustering of patients within HCPs.

RESULTS

Ten HCPs in the control group saw 301 patients, 8 HCPs in the simple prompt group saw 124, and 11 HCPs in the elaborated prompt group saw 223. The elaborated prompt arm had a higher rate of HPV vaccination (62%) than the control arm (45%): adjusted odds ratio, 2.76; 95% confidence interval, 1.07 to 7.14. The simple prompt arm did not differ significantly from the control arm with respect to HPV vaccine initiation, which might have been because of the small sample size for this arm. MenACWY and Tdap rates did not vary across the 3 arms.

CONCLUSIONS

Results suggest that an elaborated HCP-targeted reminder prompt, with suggested recommendation language, might improve rates of HPV vaccine initiation.

Chinese medical students' knowledge, attitude and practice towards human papillomavirus vaccination and their intention to recommend the vaccine

AIM

The human papillomavirus (HPV) vaccine is effective in preventing cervical cancer, but its global uptake rate in vulnerable populations is unsatisfactory. Physician's recommendation is an important determinant for vaccine uptake, but we have limited understanding on the contributing factors of physician's recommendation. This study investigated whether the knowledge, attitudes and vaccination status of medical students would affect their intention to recommend HPV vaccination.

METHODS

This is a population-representative survey of medical schools in Hong Kong.

RESULTS

Participants included 1022 Chinese medical students (46.9% of all in Hong Kong; 46.3% female). Better HPV-related knowledge and a more positive attitude towards HPV vaccination were important factors predicting vaccine uptake and intention to recommend. HPV vaccination status and intention to receive the vaccine were positively associated with intention to recommend among females.

CONCLUSION

Better HPV-related medical education may be a feasible way to promote the HPV vaccine in regions without universal coverage. Medical students who have not received the HPV vaccine should also be encouraged to receive the vaccine.

Adherence to ACIP Recommendation for Human Papillomavirus Vaccine Among US Adolescent Girls

The objective of this study was to examine correlates of human papillomavirus (HPV) vaccine use according to Advisory Committee on Immunization Practices (ACIP)'s recommendations among US adolescent girls. We used National Immunization Survey of Teens 2013 data. Based on provider-verified (n = 9403) information, 57.3, 39.1 and 19.0 % of adolescent girls, initiated, completed and completed the HPV vaccine according to ACIP's recommendation (by age 12), respectively. Hispanic race/ethnicity, a physician recommendation for HPV vaccine and ≥1 influenza vaccine in the past 3 years were all associated with a higher likelihood of compliance with ACIP's recommendation. Girls from a larger family and those whose immunization provider was a STD/school/teen clinic were less likely to receive the vaccine at the recommended age compared to a girl raised in a smaller sized family and received immunization from a hospital facility, respectively. Only one-fifth of 13-17 yo girls receive the HPV vaccine by age 12 as recommended by ACIP. Physician visits and influenza vaccination settings are opportunities to improve vaccine series completion at the recommended age.

Comparative immunogenicity and safety of human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine and 4vHPV vaccine administered according to two- or three-dose schedules in girls aged 9-14 years: Results to month 36 from a randomized trial

This observer-blind study (clinicaltrials.gov NCT01462357) compared the immunogenicity and safety of two doses (2D) of the HPV-16/18 AS04-adjuvanted vaccine (2D of AS04-HPV-16/18) vs. two or three doses of the 4vHPV vaccine [2D or 3D of 4vHPV] in 1075 healthy girls aged 9-14 years. Girls were randomized (1:1:1) to receive 2D of AS04-HPV-16/18 at months (M) 0, 6 (N = 359), 2D of 4vHPV at M0, 6 (N = 358) or 3D of 4vHPV at M0, 2, 6 (N = 358). 351, 339 and 346 girls, respectively, returned for the concluding visit at M36. Superiority was demonstrated at M7 and M12; comparison of the immune response to both vaccine antigens was made between 2D of AS04-HPV-16/18 and 2D or 3D of 4vHPV at subsequent time points in the according-to-protocol immunogenicity cohort (ATP-I; N = 958 at M36) and the total vaccinated cohort (TVC: N = 1036 at M36). HPV-16/18-specific T-cell- and B-cell-mediated immune responses and safety were also investigated. At M36, anti-HPV-16/18 ELISA responses in the 2D AS04-HPV-16/18 group remained superior to those of the 2D and 3D 4vHPV groups. In the M36 TVC, geometric mean titers were 2.78-fold (HPV-16) and 6.84-fold (HPV-18) higher for 2D of AS04-HPV-16/18 vs. 2D of 4vHPV and 2.3-fold (HPV-16) and 4.14-fold (HPV-18) higher vs. 3D of 4vHPV. Results were confirmed by vaccine pseudovirion-based neutralisation assay. Numbers of circulating CD4⁺ T cells and B cells appeared similar across groups. Safety was in line with the known safety profiles of both vaccines. In conclusion, superior HPV-16/18 antibody responses were elicited by 2D of the AS04-HPV-16/18 compared with 2D or 3D of the 4vHPV vaccine in girls aged 9-14 years.

CLINICAL TRIAL REGISTRATION

NCT0146235.

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.

Population-based HPV vaccination programmes are safe and effective: 2017 update and the impetus for achieving better global coverage

Persistent oncogenic human papillomavirus (HPV) is the cause of cervical cancer, as well as cancers of the anus, penis, vulva, vagina and oropharynx. There is good evidence that prophylactic HPV vaccines are immunogenic and effective against targeted-type HPV infections and type-specific genital lesions, including high-grade cervical intraepithelial neoplasia (CIN), when administered prior to HPV infection. There is good evidence that HPV vaccines are safe in population usage, with the most frequent adverse event being injection-site reactions. There is evidence to support some cross-protection against non-targeted types occurring following the administration of HPV vaccines. There is limited evidence suggesting that HPV vaccines may be beneficial in preventing future disease in women treated for high-grade CIN. This chapter focuses on the accumulated evidence regarding the global use of the three licensed HPV vaccines including safety, immunogenicity, duration of protection, effectiveness, coverage to date and barriers to higher coverage.

Human papillomavirus first and second generation vaccines-current status and future directions

It has been more than 10 years that the first prophylactic papillomavirus vaccine became available, although distribution has been mainly limited to the more affluent countries. The first two vaccines have been a great success, hundreds of millions of women and a much smaller number of men have been vaccinated ever since. In a few countries with high vaccination coverage, in particular Australia but also parts of Great Britain and others, clinical impact of vaccination programs is already visible and there are indications for herd immunity as well. Vaccine efficacy is higher than originally estimated and the vaccines have an excellent safety profile. Gardasil9 is a second generation HPV virus-like particle vaccine that was licensed in 2015 and there are more to come in the near future. Currently, burning questions in respect to HPV vaccination are the duration of protection - especially in regard to cross-protection - reduction of the three-dose regimen and its impact on cross-protection; and duration of response, as well as protection against oropharyngeal HPV infections. Furthermore, researchers are seeking to overcome limitations of the VLP vaccines, namely low thermal stability, cost, invasive administration, limited coverage of non-vaccine HPV types, and lack of therapeutic efficacy. In this review we summarize the current status of licensed VLP vaccines and address questions related to second and third generation HPV vaccines.

Two-dose schedules for human papillomavirus vaccine: Systematic review and meta-analysis

Simpler schedules for human papillomavirus (HPV) vaccine delivery could improve vaccine coverage and the effectiveness of cervical cancer prevention. The objective of this study was to systematically review evidence about the effects of two-dose compared with three-dose schedules for human papillomavirus (HPV) vaccine and to describe the uptake of two-dose HPV vaccination schedules globally. We searched PubMed, the Cochrane Central Registry of Controlled Trials, trials registers, and manufacturers' databases from their earliest date to February 2016. We selected randomised controlled trials and controlled clinical trials that directly compared HPV vaccine schedules with two or three doses. We extracted data on immunological and clinical outcomes and used meta-analysis where appropriate. We also described the use of two-dose HPV vaccine schedules globally. We screened 1464 items and included seven eligible noninferiority trials in 11 countries. In randomised comparisons amongst adolescent girls (three trials), geometric mean concentrations (GMC) of antibodies against HPV16 and HPV18 were non-inferior or inconclusive, up to 24months after a two-dose compared with a three-dose schedule. One trial with a clinical outcome found no persistent HPV infections occurred after either two or three doses. In non-randomised comparisons, GMC were non-inferior or superior in adolescent girls receiving the two-dose schedule compared with women receiving the three-dose schedule for at least 21months after vaccination. By February 2017, 23 low and middle income and 25 high income countries had adopted a two-dose HPV vaccination schedule. A two-dose HPV vaccine schedule provides satisfactory immunological outcomes in adolescent girls, but uptake globally is limited, particularly in countries with the highest burden of cervical cancer.

Parent Perception of Provider Interactions Influences HPV Vaccination Status of Adolescent Females

Human papillomavirus (HPV) vaccination coverage among adolescent females is well below national public health goals. Many known barriers to HPV vaccine receipt can be addressed in parent-physician conversations. This study sought to explore parent experiences and attitudes related to HPV vaccination of adolescent girls, focused on interactions with providers. We conducted a cross-sectional survey of parents using a nationally representative online panel. Among parents with ≥1 daughter aged 11 to 17 years, provider recommendations for HPV vaccine and specified age to begin the HPV vaccine series were associated with HPV vaccine status. Parents who reported their daughters were unlikely to complete the HPV series were more likely to have had no discussion of HPV vaccine with the provider. Efforts to increase HPV vaccination rates among adolescent females should continue to focus on improving provider discussion of HPV vaccine.

Less than 3 doses of the HPV vaccine - Review of efficacy against virological and disease end points

World Health Organization (WHO) recommended 2 doses of the Human Papillomavirus (HPV) vaccine for girls below 15 y on the basis of the immune-bridging studies demonstrating non-inferior immune response of 2 doses in the adolescent girls compared to 3 doses in the young adult women in whom the efficacy against disease is established. The biological nature of the antigens (virus-like particles) constituting the HPV vaccine is responsible for the vigorous antibody response that may make the third dose redundant. The protection offered by 2 doses has been demonstrated in non-randomized clinical trials to be comparable to that offered by 3 doses against incident and persistent infections of vaccine targeted HPV types. However, results emerging from the ecological and nested case-control studies embedded in the population based screening programs of different countries indicate reduced efficacy of 2 doses against virological and disease end points. Some recent studies observed the protective effect of single dose of the vaccine against incident and persistent infections of the vaccine targeted HPV types to be similar to 3 doses in spite of immunological inferiority. The sample size, duration of follow-ups and number of events were limited in these studies. Longer follow ups of the less than 3 doses cohorts in the ongoing studies as well as appropriately designed and ethically justifiable randomized studies are needed to establish the protection offered by the alternative schedules at least beyond 10 y of vaccination.

An exploration of individual- and population-level impact of the 2-dose HPV vaccination schedule in pre-adolescent girls

Since 2014, several countries have implemented a 2-dose schedule for Human papillomavirus (HPV) vaccination. Licensure of the 2-dose schedule was based on non-inferiority results from immunobridging studies, comparing the antibody levels of the 2-dose schedule in young girls to those of the 3-dose schedule in young adults. Since licensure, additional data on antibody levels and other aspects of the immune response and clinical effectiveness have become available. This review will discuss the current outcomes on immunogenicity and effectiveness together with an exploration on the population impact of 2-dose schedules from a cost-effectiveness perspective. The 2-dose schedule has important benefits, such as easier logistics, reduced expenditure, potentially higher acceptance and fewer side effects. Policymakers and registration authorities should consider whether these benefits outweigh the likely differences on individual- and population-level impact between the 2- and 3-dose schedules.

Comparative immunogenicity and safety of human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine and HPV-6/11/16/18 vaccine administered according to 2- and 3-dose schedules in girls aged 9-14 years: Results to month 12 from a randomized trial

This observer-blind study (clinicaltrials.gov NCT01462357) compared the immunogenicity and safety of 2 doses of the HPV-16/18 AS04-adjuvanted vaccine (HPV-16/18(2D)) vs. 2 or 3 doses of the HPV-6/11/16/18 vaccine (HPV-6/11/16/18(2D) and HPV-6/11/16/18(3D)) in healthy girls aged 9–14 y. Girls were randomized (1:1:1) to receive HPV-16/18(2D) at months (M) 0,6 (N = 359), HPV-6/11/16/18(2D) at M0,6 (N = 358) or HPV-6/11/16/18(3D) at M0,2,6 (N = 358). The primary objective was non-inferiority/superiority of HPV-16/18 antibodies by ELISA for HPV-16/18(2D) vs. HPV-6/11/16/18(2D) at M7 in the according-to-protocol immunogenicity cohort (ATP-I) and total vaccinated cohort, respectively. Secondary objectives included non-inferiority/superiority of HPV-16/18(2D) vs. HPV-6/11/16/18(3D) at M7, non-inferiority/superiority at M12, HPV-16/18 neutralizing antibodies, frequencies of T-cells/B-cells, reactogenicity and safety. Antibody responses at M7 for HPV-16/18(2D) were superior to those for HPV-6/11/16/18(2D) and HPV-6/11/16/18(3D) (lower limit of 95% confidence interval for geometric mean titer ratio (GMR) was >1): HPV-16/18(2D)/HPV-6/11/16/18(2D) GMRs were 1.69 [1.49–1.91] for anti-HPV-16 and 4.52 [3.97–5.13] for anti-HPV-18; HPV-16/18(2D)/HPV-6/11/16/18(3D) GMRs were 1.72 [1.54–1.93] for anti-HPV-16 and 3.22 [2.82–3.68] for anti-HPV-18; p = 0.0001 for all comparisons. Non-inferiority/superiority was also demonstrated at M12. Among initially seronegative girls in the ATP-I, neutralizing antibody titers were at least 1.8-fold higher for HPV-16/18(2D) vs. HPV-6/11/16/18(2D) and HPV-6/11/16/18(3D) at M7 and M12. Frequencies of HPV-16/18-specific T-cells and B-cells were in similar ranges between groups. Reactogenicity and safety were in line with the known profile of each vaccine. In conclusion, superior HPV-16/18 antibody responses were elicited by 2 doses of the HPV-16/18 AS04-adjuvanted vaccine compared with 2 or 3 doses of the HPV-6/11/16/18 vaccine in girls (9–14 years).

The potential impact of prophylactic human papillomavirus vaccination on oropharyngeal cancer

The incidence of oropharyngeal cancer (OPC) is significantly increasing in the United States. Given that these epidemiologic trends are driven by human papillomavirus (HPV), the potential impact of prophylactic HPV vaccines on the prevention of OPC is of interest. The primary evidence supporting the approval of current prophylactic HPV vaccines is from large phase 3 clinical trials focused on the prevention of genital disease (cervical and anal cancer, as well as genital warts). These trials reported vaccine efficacy rates of 89% to 98% for the prevention of both premalignant lesions and persistent genital infections. However, these trials were designed before the etiologic relationship between HPV and OPC was established. There are differences in the epidemiology of oral and genital HPV infection, such as differences in age and sex distributions, which suggest that the vaccine efficacy observed in genital cancers may not be directly translatable to the cancers of the oropharynx. Evaluation of vaccine efficacy is challenging in the oropharynx because no premalignant lesion analogous to cervical intraepithelial neoplasia in cervical cancer has yet been identified. To truly investigate the efficacy of these vaccines in the oropharynx, additional clinical trials with feasible endpoints are needed. Cancer 2016;122:2313-2323. © 2016 American Cancer Society.

Human papilloma virus vaccination: Review article and an update

Human papilloma virus (HPV) is sexually transmitted and associated with uterine cervix, vaginal, and vulvar cancers in females, oropharyngeal and anal cancer in both genders, and penile cancer in males. Moreover, genital warts are benign tumors which are HPV-related and can occur in both genders. This is a review of HPV structure, HPV infection transmission, the global impact of HPV and its associated diseases, HPV vaccines and their efficacy and safety, public acceptance of HPV vaccines, the obstacles for its acceptance and strategies to address the barriers. Cervarix (a bivalent vaccine with protection against HPV types 16 and 18) and Gardasil (a quadrivalent vaccine with protection against HPV types 6, 11, 16 and 18) are 2 recommended vaccines. The longest follow up of 9.4 years has shown efficacy and protection of the vaccine against HPV types 16 and 18. The adverse effects have been minimal and the vaccine is considered safe. Numerous studies are conducted to follow the vaccinated individuals to better understand the effect of HPV vaccine on incidence of HPV-related cancers and precancerous lesions.

Randomized Open Trial Comparing 2-Dose Regimens of the Human Papillomavirus 16/18 AS04-Adjuvanted Vaccine in Girls Aged 9-14 Years Versus a 3-Dose Regimen in Women Aged 15-25 Years

Background. This randomized, open trial compared regimens including 2 doses (2D) of human papillomavirus (HPV) 16/18 AS04-adjuvanted vaccine in girls aged 9–14 years with one including 3 doses (3D) in women aged 15–25 years.

Methods. Girls aged 9–14 years were randomized to receive 2D at months 0 and 6 (M0,6; (n = 550) or months 0 and 12 (M0,12; n = 415), and women aged 15–25 years received 3D at months 0, 1, and 6 (n = 482). End points included noninferiority of HPV-16/18 antibodies by enzyme-linked immunosorbent assay for 2D (M0,6) versus 3D (primary), 2D (M0,12) versus 3D, and 2D (M0,6) versus 2D (M0,12); neutralizing antibodies; cell-mediated immunity; reactogenicity; and safety. Limits of noninferiority were predefined as <5% difference in seroconversion rate and <2-fold difference in geometric mean antibody titer ratio.

Results. One month after the last dose, both 2D regimens in girls aged 9–14 years were noninferior to 3D in women aged 15–25 years and 2D (M0,12) was noninferior to 2D (M0,6). Geometric mean antibody titer ratios (3D/2D) for HPV-16 and HPV-18 were 1.09 (95% confidence interval, .97–1.22) and 0.85 (.76–.95) for 2D (M0,6) versus 3D and 0.89 (.79–1.01) and 0.75 (.67–.85) for 2D (M0,12) versus 3D. The safety profile was clinically acceptable in all groups.

Conclusions. The 2D regimens for the HPV-16/18 AS04-adjuvanted vaccine in girls aged 9–14 years (M0,6 or M0,12) elicited HPV-16/18 immune responses that were noninferior to 3D in women aged 15–25 years.

Clinical Trials Registration. NCT01381575.

Immunogenicity and HPV infection after one, two, and three doses of quadrivalent HPV vaccine in girls in India: a multicentre prospective cohort study

BACKGROUND

An increase in worldwide HPV vaccination could be facilitated if fewer than three doses of vaccine are as effective as three doses. We originally aimed to compare the immunogenicity and frequency of persistent infection and cervical precancerous lesions caused by vaccine-targeted HPV after vaccination with two doses of quadrivalent vaccine on days 1 and 180 or later, with three doses on days 1, 60, and 180 or later, in a cluster-randomised trial. Suspension of the recruitment and vaccination due to events unrelated to our study meant that some enrolled girls could not be vaccinated and some vaccinated girls received fewer than the planned number of vaccinations by default. As a result, we re-analysed our data as an observational cohort study.

METHODS

Our study was designed to be done in nine locations (188 clusters) in India. Participants were unmarried girls aged 10-18 years vaccinated in four cohorts: girls who received three doses of vaccine on days 1, 60, and 180 or later, two doses on days 1 and 180 or later, two doses on days 1 and 60 by default, and one dose by default. The primary outcomes were immunogenicity in terms of L1 genotype-specific binding antibody titres, neutralising antibody titres, and antibody avidity after vaccination for the vaccine-targeted HPV types 16, 18, 6, and 11 and incident and persistent infections with these HPVs. Analysis was per actual number of vaccine doses received. This study is registered with ISRCTN, number ISRCTN98283094; and with ClinicalTrials.gov, number NCT00923702.

FINDINGS

Vaccination of eligible girls was initiated on Sept 1, 2009, and continued until April 8, 2010. Of 21 258 eligible girls identified at 188 clusters, 17 729 girls were recruited from 178 clusters before suspension. 4348 (25%) girls received three doses, 4979 (28%) received two doses on days 1 and 180 or later, 3452 (19%) received two doses at days 1 and 60, and 4950 (28%) received one dose. Immune response in the two-dose HPV vaccine group was non-inferior to the three-dose group (median fluorescence intensity ratio for HPV 16 1·12 [95% CI 1·02-1·23] and for HPV 18 1·04 [0·92-1·19]) at 7 months, but was inferior in the two-dose default (0·33 [0·29-0·38] for HPV 16 and 0·51 [0·43-0·59] for HPV 18) and one-dose default (0·09 [0·08-0·11] for HPV 16 and 0·12 [0·10-0·14] for HPV 18) groups at 18 months. The geometric mean avidity indices after fewer than three doses by design or default were non-inferior to those after three doses of vaccine. Fewer than three doses by design and default induced detectable concentrations of neutralising antibodies to all four vaccine-targeted HPV types, but at much lower concentration after one dose. Cervical samples from 2649 participants were tested and the frequency of incident HPV 16, 18, 6, and 11 infections was similar irrespective of the number of vaccine doses received. The testing of at least two samples from 838 participants showed that there was no persistent HPV 16 or 18 infections in any study group at a median follow-up of 4·7 years (IQR 4·2-5·1).

INTERPRETATION

Despite the limitations imposed by the suspension of the HPV vaccination, our findings lend support to the WHO recommendation of two doses, at least 6 months apart, for routine vaccination of young girls. The short-term protection afforded by one dose of HPV vaccine against persistent infection with HPV 16, 18, 6, and 11 is similar to that afforded by two or three doses of vaccine and merits further assessment.

FUNDING

Bill & Melinda Gates Foundation.