Immunologic responses following administration of a vaccine targeting human papillomavirus Types 6, 11, 16, and 18

Human papillomavirus therapeutic vaccines: targeting viral antigens as immunotherapy for precancerous disease and cancer

Infections with oncogenic HPV types have the potential to lead to the induction of several types of cancer, notably cervical, vulvar, anal, and head and neck cancer. While prophylactic vaccines are currently available and show high efficacy against the establishment of HPV infection, low rates of initiation and lower rates of completion of the vaccination regimen, as well as the lack of an opportunity to be vaccinated prior to infection, has lead to the development of a patient population for whom no immune-based therapy for infection is available. In the current review the authors examine clinical approaches to HPV-targeted immune therapies, the bulk of which target the regulatory proteins E6 and E7 that are constitutively expressed in HPV-associated cancer cells. Early studies demonstrate a correlation between induction of T-cell responses and clearance of HPV-associated precancerous lesions. The clinical data corroborates these findings and highlight the importance of Th1 skewing. Improvements in our understanding of tumor immunology and development of more potent Th1-directed vaccine platforms make it feasible to foresee a HPV therapeutic vaccine in the coming years.

Immunogenicity of quadrivalent human papillomavirus vaccine in organ transplant recipients

Solid organ transplant recipients are at risk of morbidity from human papillomavirus (HPV)-related diseases. Quadrivalent HPV vaccine is recommended for posttransplant patients but there are no data on vaccine immunogenicity. We determined the immunogenicity of HPV vaccine in a cohort of young adult transplant patients. Patients were immunized with three doses of quadrivalent HPV vaccine containing viral types 6, 11, 16 and 18. Immunogenicity was determined by type-specific viral-like protein ELISA. Four weeks after the last dose of vaccine, a vaccine response was seen in 63.2%, 68.4%, 63.2% and 52.6% for HPV 6, 11, 16 and 18, respectively. Factors that led to reduced immunogenicity were vaccination early after transplant (p = 0.019), having a lung transplant (p = 0.007) and having higher tacrolimus levels (p = 0.048). At 12 months, there were significant declines in antibody titer for all HPV types although the number of patients who remained seropositive did not significantly differ. The vaccine was safe and well tolerated. We show suboptimal immunogenicity of HPV vaccine in transplant patients. This is important for counseling patients who choose to receive this vaccine. Further studies are needed to determine an optimal HPV vaccine type and schedule for this population.

Development and impact of human papillomavirus vaccines

Cervical cancer is a global health crisis that disproportionately affects developing nations and underserved populations. Two vaccines targeting HPV-16 and 18, which account for 70% of invasive cervical carcinomas, are licensed in the United States and numerous countries worldwide. Both vaccine formulations have shown excellent efficacy with minimal toxicity. Numerous questions remain, including cost-effectiveness, vaccination of males, societal acceptance of HPV vaccination, and cervical dysplasia screening in the HPV-immunized population. Access to vaccination for underserved populations both in developed and resource-poor nations remains an issue. Multivalent vaccines that encompass additional oncogenic HPV strains are under development.

Immunogenicity of quadrivalent HPV vaccine among girls 11 to 13 Years of age vaccinated using alternative dosing schedules: results 29 to 32 months after third dose

BACKGROUND

 Immune response to quadrivalent human papillomavirus (HPV) vaccine delivered at 0, 2, and 6 months in young adolescent females plateaus around 24 months after immunization. Antibody levels >24 months postvaccination using extended dosing schedules is unknown.

METHODS

 We conducted a follow-up immunogenicity study of adolescent girls in Vietnam who participated in a noninferiority trial to investigate whether immune responses using 3 alternative dosing schedules (0, 3, 9 months; 0, 6, 12 months; or 0, 12, 24 months) are noninferior to the standard schedule at >2 years after immunization.

RESULTS

 Quadrivalent HPV vaccine immunogenicity delivered on 3 alternative dosing schedules was noninferior for types 6, 11, 16, and 18 at 32 months post-dose 3 compared to the standard schedule. Pre-dose 3 antibody levels for the 0, 12, 24 month schedule were similar to those measured 32-months post-dose 3.

CONCLUSIONS

 We found similar antibody concentrations ≥29 months after 3 doses of HPV vaccine regardless of dose-timing, and extended schedules do not produce inferior immune responses. Our findings also suggested that 2 doses of HPV vaccine delivered at 0 and 12 months might afford similar protection. Evidence supporting dosing flexibility could be important for national HPV vaccination policies.

Concomitant anal and cervical human papillomavirusV infections and intraepithelial neoplasia in HIV-infected and uninfected women

OBJECTIVE

To assess factors associated with concomitant anal and cervical human papillomavirus (HPV) infections in HIV-infected and at-risk women.

DESIGN

A study nested within the Women's Interagency HIV Study (WIHS), a multicenter longitudinal study of HIV-1 infection in women conducted in six centers within the United States.

METHODS

Four hundred and seventy HIV-infected and 185 HIV-uninfected WIHS participants were interviewed and examined with anal and cervical cytology testing. Exfoliated cervical and anal specimens were assessed for HPV using PCR and type-specific HPV testing. Women with abnormal cytologic results had colposcopy or anoscopy-guided biopsy of visible lesions. Logistic regression analyses were performed and odds ratios (ORs) measured the association for concomitant anal and cervical HPV infection.

RESULTS

One hundred and sixty-three (42%) HIV-infected women had detectable anal and cervical HPV infection compared with 12 (8%) of the HIV-uninfected women (P  <  0.001). HIV-infected women were more likely to have the same human papillomavirus (HPV) genotype in the anus and cervix than HIV-uninfected women (18 vs. 3%, P  < 0.001). This was true for both oncogenic (9 vs. 2%, P  =  0.003) and nononcogenic (12 vs. 1%, P < 0.001) HPV types. In multivariable analysis, the strongest factor associated with both oncogenic and nononcogenic concomitant HPV infection was being HIV-infected (OR = 4.6 and OR  = 16.9, respectively). In multivariable analysis of HIV-infected women, CD4 cell count of less than 200 was the strongest factor associated with concomitant oncogenic (OR  = 4.2) and nononcogenic (OR  =  16.5) HPV infection.

CONCLUSION

HIV-infected women, particularly those women with low CD4 cell counts, may be good candidates for HPV screening and monitoring for both cervical and anal disease.

Are the currently existing anti-human papillomavirus vaccines appropriate for the developing world?

Cervical cancer prevention is expected to be achieved by vaccination of girls 2-3 years before sexual debut, and cervical smear cytology follow-up. The existing human papillomavirus (HPV) vaccines target the low-risk 6 and 11, and the high-risk 16 and 18 subtypes, the most common agents of ano-genital pre-invasive and invasive lesions. We conducted the review by searching PubMed using the terms "HPV," "HPV subtypes," "developing world," and "HPV-vaccine" to retrieve articles published between 2000 and 2011. We focused on studies that were relevant to the developing world. The proposed vaccination policy is currently unachievable in the developing world because of the cost of the vaccine, the lack of adequate cytology and follow-up infrastructures. Moreover, the subtypes of HPV involved in cervical pathology, their associations, and natural history (clearance and persistence rates) differ from the industrialized world. Therefore, the current bivalent and quadrivalent anti-HPV vaccines are unlikely to achieve their target in the developing world. It follows from published data that there is an obligation of the pharmaceutical industry and of the public-health policy makers not to embark on mass vaccination campaigns without thorough information and investigation of the local relevance.

Human papillomavirus vaccination: current indications and future directions

Human papillomavirus (HPV) is one of the most common sexually transmitted infections affecting both men and women worldwide. The development of the prophylactic HPV vaccines is a significant pharmaceutical innovation with potential to reduce HPV-related morbidity. However, barriers to the universal use and acceptability of the HPV vaccines continue to exist in both economically privileged and disadvantaged countries. It may be decades before the impact of preventive vaccines on HPV-related diseases caused by the considerable burden of HPV infections will be seen. Collaborative efforts must continue to promote vaccine implementation.

Immunogenicity and safety of the human papillomavirus 6, 11, 16, 18 vaccine in HIV-infected young women

BACKGROUND

The objective of this study was to determine whether the 3-dose quadrivalent human papillomavirus (HPV) vaccine series (HPV-6, -11, -16, -18) is immunogenic and safe in young women infected with human immunodeficiency virus (HIV).

METHODS

We enrolled 99 women aged 16-23 years in a phase 2, open-label, multicenter trial, conducted from 2008 to 2011 by the Adolescent Medicine Trials Network for HIV/AIDS Interventions. Outcome measures were immunogenicity 4 weeks after dose 3, measured by (1) geometric mean titers (GMTs) and (2) seroconversion rates for HPV-6, -11, -16, and -18, among those seronegative and HPV DNA negative for each type. Immune responses were compared to those of a historical comparison group of HIV-negative women (n = 267) using univariate methods. Clinical and laboratory adverse events were assessed after each dose.

RESULTS

The mean age of subjects was 21.4 years; 80% were non-Hispanic black, 69 were not taking antiretroviral therapy (ART), and 30 were taking ART. No differences in GMTs were noted among participants taking ART vs the comparison group, but GMTs were lower in participants not taking ART vs the comparison group for HPV-16 (2393 vs 3892 milli-Merck units per milliliter [mMU/mL], P = .012) and HPV-18 (463 vs 801 mMU/mL, P = .003). Seroconversion rates were 100% for HPV-6, -11, -16, and -18 among participants taking ART. Rates ranged from 92.3% (for HPV-18) to 100.0% (for HPV-6) among participants not taking ART. One severe adverse event (fatigue) was noted.

CONCLUSIONS

In a sample of HIV-infected women who were HPV DNA and HPV seronegative, immune responses to HPV vaccination were generally robust and the vaccine was well tolerated.

Human Papillomavirus-mediated cervical cancer awareness and Gardasil vaccination: a pilot survey among North Indian women

Human Papillomavirus (HPV)-mediated cervical cancer is a leading cause of morbidity and mortality in women worldwide, including Indian women. Cervical cancer control and prevention strategies are being adopted in developing nations to reduce the increasing burden of HPV infection in the vaccine era. The present study, therefore, aimed to evaluate cervical cancer awareness and knowledge of Gardasil vaccination in North Indian women. A pilot survey was conducted among 103 women of North Indian ethnicity residing in Lucknow/adjoining areas in state of Uttar Pradesh, during routine screening/clinic visits from June 2012 to December 2012. The study subjects were interviewed in either Hindi or English; subsequently the awareness of HPV-mediated cervical cancer and knowledge of Gardasil vaccination was assessed in terms of "yes", "no" and "no response". The study was approved by the Institutional Review Board. Written informed consent was taken from the participants. Overall, the response of participants (n = 103) in our single-centre survey-based pilot study was well-defined. The response regarding HPV-mediated cervical cancer awareness in terms of "yes", "no" and "no response" among the study subjects was 43.7, 44.7 and 11.6 %, respectively. Furthermore, in response to knowledge of HPV vaccine Gardasil, out of 103 subjects, 28.1 % answered "yes" while 37.9 and 34.0 % stated "no" and "no response", respectively. Our pilot survey may help in assessing knowledge of HPV-mediated cervical cancer and Gardasil vaccination awareness in women, and accordingly develop cost-effective cervical cancer control and prevention/public health counseling sessions in a clinical setting.

Human papillomavirus vaccines--immune responses

Prophylactic human papillomavirus (HPV) virus-like particle (VLP) vaccines are highly effective. The available evidence suggests that neutralising antibody is the mechanism of protection. However, despite the robust humoral response elicited by VLP vaccines, there is no immune correlate, no minimum level of antibody, or any other immune parameter, that predicts protection against infection or disease. The durability of the antibody response and the importance of antibody isotype, affinity and avidity for vaccine effectiveness are discussed. Once infection and disease are established, then cellular immune responses are essential to kill infected cells. These are complex processes and understanding the local mucosal immune response is a prerequisite for the rational design of therapeutic HPV vaccines. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

A randomized, observer-blinded immunogenicity trial of Cervarix(®) and Gardasil(®) Human Papillomavirus vaccines in 12-15 year old girls

Background

The current generation of Human Papillomavirus (HPV) vaccines, Cervarix® and Gardasil®, exhibit a high degree of efficacy in clinical trials against the two high-risk (HR) genotypes represented in the vaccines (HPV16 and HPV18). High levels of neutralizing antibodies are elicited against the vaccine types, consistent with preclinical data showing that neutralizing antibodies can mediate type-specific protection in the absence of other immune effectors. The vaccines also confer protection against some closely related non-vaccine HR HPV types, although the vaccines appear to differ in their degree of cross-protection. The mechanism of vaccine-induced cross-protection is unknown. This study sought to compare the breadth and magnitudes of neutralizing antibodies against non-vaccine types elicited by both vaccines and establish whether such antibodies could be detected in the genital secretions of vaccinated individuals.

Methods and Findings

Serum and genital samples were collected from 12–15 year old girls following vaccination with either Cervarix® (n = 96) or Gardasil® (n = 102) HPV vaccine. Serum-neutralizing antibody responses against non-vaccine HPV types were broader and of higher magnitude in the Cervarix®, compared to the Gardasil®, vaccinated individuals. Levels of neutralizing and binding antibodies in genital secretions were closely associated with those found in the serum (r = 0.869), with Cervarix® having a median 2.5 (inter-quartile range, 1.7–3.5) fold higher geometric mean HPV-specific IgG ratio in serum and genital samples than Gardasil® (p = 0.0047). There was a strong positive association between cross-neutralizing antibody seropositivity and available HPV vaccine trial efficacy data against non-vaccine types.

Conclusions

These data demonstrate for the first time that cross-neutralizing antibodies can be detected at the genital site of infection and support the possibility that cross-neutralizing antibodies play a role in the cross-protection against HPV infection and disease that has been reported for the current HPV vaccines.

Trial Registration

ClinicalTrials.gov NCT00956553

Vaccine delivery using nanoparticles

Vaccination has had a major impact on the control of infectious diseases. However, there are still many infectious diseases for which the development of an effective vaccine has been elusive. In many cases the failure to devise vaccines is a consequence of the inability of vaccine candidates to evoke appropriate immune responses. This is especially true where cellular immunity is required for protective immunity and this problem is compounded by the move toward devising sub-unit vaccines. Over the past decade nanoscale size (<1000 nm) materials such as virus-like particles, liposomes, ISCOMs, polymeric, and non-degradable nanospheres have received attention as potential delivery vehicles for vaccine antigens which can both stabilize vaccine antigens and act as adjuvants. Importantly, some of these nanoparticles (NPs) are able to enter antigen-presenting cells by different pathways, thereby modulating the immune response to the antigen. This may be critical for the induction of protective Th1-type immune responses to intracellular pathogens. Their properties also make them suitable for the delivery of antigens at mucosal surfaces and for intradermal administration. In this review we compare the utilities of different NP systems for the delivery of sub-unit vaccines and evaluate the potential of these delivery systems for the development of new vaccines against a range of pathogens.

Human papillomavirus screening in north Indian women

OBJECTIVES

Human papillomavirus (HPV) is the major etiological agent of cervical cancer, a leading cause of morbidity and mortality in women worldwide. Screening strategies for reducing the burden of HPV-mediated carcinogenesis are emerging as an effective means for cervical cancer control and prevention in developing countries. Our study, therefore, aimed to identify HPV infection status in North Indian women during random population screening.

METHODOLOGY

Cervical/vaginal exfoliated cells and/or Pap smear specimens were collected from 890 women of North Indian ethnicity residing in Lucknow and adjoining areas, during random population screening from June 2009-March 2012. HPV viral loads in clinical specimens were determined by the Hybrid Capture (hc)-2 HPV DNA assay, and subsequently, positive/negative/borderline HPV status was calculated.

RESULTS

The HPV incidence in the present study was 11.7%. 751 out of a total of 890 women (84.4%) participating in our HPV screening program were HPV negative (HPV -), 104 (11.7%) tested positive (HPV +) while 35 (3.9%) showed borderline (HPV *) infection status. Furthermore, in the HPV + subjects (N=104), 18 (17.3%) showed strong positivity. We observed that HPV positivity tends to increase with age in North Indian women; the higher the viral load with increasing age, higher is the susceptibility to HPV-mediated cervical cancer.

CONCLUSIONS

HPV viral load/genotyping may help in identifying women at risk of developing cervical cancer. However, cost- effective HPV screening protocols with a wider population coverage are warranted so as to reduce the burden of cervical cancer in women worldwide in the vaccine-era.

Vaccine delivery using nanoparticles

Vaccination has had a major impact on the control of infectious diseases. However, there are still many infectious diseases for which the development of an effective vaccine has been elusive. In many cases the failure to devise vaccines is a consequence of the inability of vaccine candidates to evoke appropriate immune responses. This is especially true where cellular immunity is required for protective immunity and this problem is compounded by the move toward devising sub-unit vaccines. Over the past decade nanoscale size (<1000 nm) materials such as virus-like particles, liposomes, ISCOMs, polymeric, and non-degradable nanospheres have received attention as potential delivery vehicles for vaccine antigens which can both stabilize vaccine antigens and act as adjuvants. Importantly, some of these nanoparticles (NPs) are able to enter antigen-presenting cells by different pathways, thereby modulating the immune response to the antigen. This may be critical for the induction of protective Th1-type immune responses to intracellular pathogens. Their properties also make them suitable for the delivery of antigens at mucosal surfaces and for intradermal administration. In this review we compare the utilities of different NP systems for the delivery of sub-unit vaccines and evaluate the potential of these delivery systems for the development of new vaccines against a range of pathogens.

Assessment of human papilloma virus infection in adult laryngeal papilloma using a screening test

OBJECTIVES

Human papilloma virus (HPV) infection is involved in both juvenile and adult laryngeal papilloma. We wished to determine which types of adult laryngeal papilloma were clinically related to HPV infection. We hypothesized that multiple-site and recurrent papillomas would have a strong relationship to HPV and conducted the present study to test this hypothesis.

METHODS

Thirteen male patients with adult laryngeal papilloma who underwent resection of papilloma between August 2006 and September 2009 were studied. We examined the relationships between whether the tumor was solitary or multiple, presence or absence of recurrence after surgery, and HPV infection. High-risk HPV types (HPV-DNA types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68) and low-risk HPV types (6, 11, 42, 43, and 44) were tested by a liquid-phase hybridization method. In addition, HPV typing was performed for patients positive for low-risk HPV types. Twenty patients with laryngeal carcinoma or laryngeal leukoplakia were enrolled as the control group.

RESULTS

In the laryngeal papilloma group, all patients tested were negative for high-risk HPV and 69.2% were positive for low-risk HPV. Typing performed for seven of the patients who tested positive for low-risk HPV showed that one patient was positive for HPV-11, whereas the remaining six patients were positive for HPV-6. All patients with recurrent laryngeal papillomatosis (RLP) were positive for low-risk HPV. All patients who were positive for low-risk HPV had RLP. Tumor samples from repeat operations were positive for low-risk HPV in all patients tested. HPV was not detected in the control group.

CONCLUSIONS

The relationship between RLP and low-risk HPV was strong, with all cases that were positive for low-risk HPV showing recurrence. Tumor tissue resected at the time of repeat surgery was positive for low-risk HPV in all cases tested.

Cervical cancer in India and HPV vaccination

Cervical cancer, mainly caused by Human Papillomavirus infection, is the leading cancer in Indian women and the second most common cancer in women worldwide. Though there are several methods of prevention of cervical cancer, prevention by vaccination is emerging as the most effective option, with the availability of two vaccines. Several studies have been published examining the vaccine's efficacy, immunogenicity and safety. Questions and controversy remain regarding mandatory vaccination, need for booster doses and cost-effectiveness, particularly in the Indian context.

Novel animal papillomavirus sequences and accurate phylogenetic placement

All amniotes are probably infected by specific papillomaviruses (PVs), but knowledge about PV diversity remains sparse. An insufficient taxon sampling, and a focus on humans as hosts, may perturb phylogenetic analyses leading to wrong conclusions about PV evolution. We performed a systematic approach to explore the diversity of PVs combining rolling circle amplification with the use of "universal" primers to search for the presence of novel PV sequences in animal samples. We communicate 12 sequences putatively corresponding to novel PVs gained from 10 host species in eight mammal families: Bovidae, Canidae, Cervidae, Equidae, Hominidae, Phocoenidae, Procyonidae and Pteropodidae. The phylogenetic position of the new sequences was inferred with an evolutionary placement algorithm under a Maximum Likelihood framework using a pre-computed, well-resolved tree constructed with the E1-E2-L1 gene sequences as a backbone. The new sequences were phylogenetically diverse and could be respectively placed with confidence within all four PV crown groups. The prevailing presence of sequences from the crown groups Alpha+Omikron-PVs and Beta+Xi-PVs may correspond to an increased viral diversity in these taxa, or rather reflect a combination of anthropocentric bias and preferential amplification from commonly used "universal" primers. Our results combined with literature data support the view that the number and diversity of animal PVs is overwhelmingly large.

The cost effectiveness of human papillomavirus vaccines: a systematic review

INTRODUCTION

Human papillomavirus (HPV) is one of the world's most common sexually transmitted infections, and has been associated with a number of cervical and non-cervical diseases, including cancer. HPV vaccines have been licensed for use in females for some time, but the quadrivalent vaccine has only recently become licensed for use in males. Many countries have adopted a vaccination programme for adolescent females based on results of cost-effectiveness analyses. However, given the new indications for use of the vaccine in males, decision makers require information on the cost effectiveness of vaccinating males in order to make policy decisions on whether or not to fund such programmes.

OBJECTIVE

Our objective was to conduct a qualitative systematic review to update a previously conducted review of HPV vaccine studies.

METHODS

Articles were obtained from an extensive literature search to determine the cost effectiveness of implementing an HPV vaccination programme with routine cervical cancer screening. A total of 29 studies were included in this review. Seventeen of the included articles looked only at cervical disease outcomes, and 12 studies also included non-cervical disease outcomes. Four studies explored the economic impact of vaccinating both boys and girls. One study focused on a population of men who have sex with men (MSM).

RESULTS

While different model structures, input parameters and baseline assumptions were used, the consistent message in studies that focused on female-only vaccination programmes was that routine vaccination of females is cost effective compared with cervical cancer screening alone.

DISCUSSION

Based on the currently available literature, it appears that the addition of boys to a vaccination programme generally exceeds traditional cost-effectiveness thresholds. The MSM population represents a potential additional target for routine HPV vaccination; however, more cost-effectiveness studies are required before making such a policy change.

Economic modelling assessment of the HPV quadrivalent vaccine in Brazil: a dynamic individual-based approach

We examined the cost-effectiveness of the quadrivalent HPV vaccine for the pre-adolescent female population of Brazil. Using demographic, epidemiological and cancer data, we developed a dynamic individual-based model representing the natural history of HPV/cervical cancer as well as the impact of screening and vaccination programmes. Assuming the current screening strategies, we calculated the incremental cost-effectiveness ratio (ICER) for cohorts with and without vaccination taking into account different combinations of vaccination coverage (50%, 70%, 90%) and cost per vaccinated woman (US$25, US$55, US$125, US$556). The results varied from cost-saving (coverage 50% or 70% and cost per vaccinated woman US$25) to 5950 US$/QALY (coverage 90% and cost per vaccinated 556 US$). In a scenario in which a booster shot was needed after 10 years in order to secure lifelong protection, the ICER resulted in 13,576 US$/QALY. Considering the very cost-effective and cost-effective thresholds based on Brazil's GDP per capita, apart from the booster scenario which would be deemed cost-effective, all the other scenarios would be deemed very cost-effective. Both the cost per dose of vaccine and discount rate (5%) had an important impact on the results. Vaccination in addition to the current screening programme is likely to save years of life and, depending on the cost of vaccination, may even save resources. Price negotiations between governments and manufacturers will be paramount in determining that the vaccine not only represents good value for money, but is also affordable in middle-income countries like Brazil.

Cervical, anal and oral HPV in an adolescent inner-city health clinic providing free vaccinations

Objectives

Published human papillomavirus (HPV) vaccine trials indicate efficacy is strongest for those naive to the vaccine-types. However, few high-risk young women have been followed and cervical HPV has been the predominant outcome measure.

Methods

We collected cervical and anal swabs, as well as oral rinse specimens from 645 sexually active inner-city young females attending a large adolescent health-clinic in New York City that offers free care and HPV vaccination. Specimens were tested for HPV-DNA using a MY09/MY11-PCR system. Type-specific prevalence of HPV at each anatomic site was compared for individuals by vaccination dose using generalized estimating equation logistic regression models.

Results

The majority of subjects reported being of non-Caucasian (92%) and/or Hispanic ethnicity (61%). Median age was 18 years (range:14–20). All had practiced vaginal sex, a third (33%) practiced anal sex, and most (77%) had also engaged in oral sex. At enrollment, 21% had not received the vaccine and 51% had received three doses. Prevalent HPV infection at enrollment was detected in 54% of cervical, 42% of anal and 20% of oral specimens, with vaccine types present in 7%, 6% and 1% of specimens, respectively. Comparing prevalence for vaccine types, the detection of HPV in the cervix of vaccinated compared to unvaccinated adolescents was significantly reduced: HPV6/11 (odds ratio [OR] = 0.19, 95%CI:0.06–0.75), HPV16 (OR = 0.31, 95%CI:0.11–0.88) and HPV18 (OR = 0.14, 95%CI:0.03–0.75). For anal HPV, the risk of detecting vaccine types HPV6/11 (OR = 0.27, 95%CI:0.10–0.72) and HPV18(OR = 0.12, 95%CI:0.01–1.16) were significantly reduced for vaccinated adolescents however, the risk for HPV16 was not significantly decreased (OR = 0.63, 95%CI:0.18–2.20).

Conclusion

HPV Prevalence is extremely high in inner-city female adolescents. Administration of the HPV vaccine reduced the risk for cervical HPV; however continued follow-up is required to assess the protection for HPV at all sites in young women with high exposure.

Comparison of the immune responses to the CIA06-adjuvanted human papillomavirus L1 VLP vaccine with those against the licensed HPV vaccine Cervarix™ in mice

CIA05 is a toll-like receptor (TLR) 4 agonist derived from an Escherichia coli lipopolysaccharide (LPS) mutant and has been shown to have potential as a vaccine adjuvant. In this study, we investigated the immunopotentiating activity of the adjuvant system CIA06, which is comprised of CIA05 and aluminum hydroxide (alum), when used with the human papillomavirus (HPV) L1 virus-like particles (VLPs) vaccine. BALB/c mice were immunized intramuscularly three times at 2-week intervals with HPV16 L1 VLPs alone or in the presence of various combinations of CIA05 and alum, and the immune responses were assessed. We found that the combination of CIA05 and alum at a ratio of 1:50 (designated CIA06B) yielded the highest immune response in terms of serum anti-HPV L1 VLP IgG antibody titers, splenocyte interferon (IFN)-γ secretion, and antigen-specific memory B cell responses. The immunogenicity of the CIA06B-adjuvanted HPV16/18 L1 VLP vaccine was compared with that of the currently licensed HPV vaccine Cervarix™. The CIA06B-adjuvanted vaccine was similar to Cervarix™ with regard to eliciting serum antigen-specific IgG antibodies and virus-neutralizing antibodies but more effective at inducing splenic cytokine production and memory B cells. We also observed that the antigen-specific IgG antibody titers, splenic IFN-γ secretion and memory B cells induced by the CIA06B-adjuvanted HPV vaccine remained high up to 24 weeks post-immunization. Based on these data, we concluded that CIA06B may have potential as an adjuvant in a potent prophylactic vaccine against HPV infection.

Age of recipient and number of doses differentially impact human B and T cell immune memory responses to HPV vaccination

Vaccination is one of the most effective medical interventions. However, optimization of existing as well as design of new vaccines is still mostly conducted empirically; a rational approach to vaccine design is largely prohibited by the lack of insight into the relevant mechanisms underlying immune-mediated protection. To delineate the impact of variables on immune memory formation following vaccination, we took advantage of a trial assessing the role of the age of the recipient and the number of administered doses of the quadrivalent HPV vaccine in a well-characterized longitudinal cohort of girls and young women. We found that age of the recipient and the number of doses administered differentially impact the development of B and T cell memory. Specifically, age of the recipient significantly impacted generation of HPV 18-specific B cell memory, while the number of vaccine doses displayed a significant effect on the development of HPV-specific T cell memory. Our data indicate that rational design of vaccines has to be tailored according to the desired induction of B and/or T cell memory.

Research advances in plant-made flavivirus antigens

Outbreaks of flaviviruses such as dengue (DV), yellow fever (YFV), Japanese encephalitis (JEV), tick-borne encephalitis (TBEV) and West Nile (WNV) affect numerous countries around the world. The fast spread of these viruses is the result of increases in the human population, rapid urbanisation and globalisation. While vector control is an important preventive measure against vector-borne diseases, it has failed to prevent the spread of these diseases, particularly in developing countries where the implementation of control measures is intermittent. As antiviral drugs against flaviviruses are not yet available, vaccination remains the most important tool for prevention. Although human vaccines for YFV, TBEV and JEV are available, on-going vaccination efforts are insufficient to prevent infection. No vaccines against DENV and WNV are available. Research advances have provided important tools for flavivirus vaccine development, such as the use of plants as a recombinant antigen production platform. This review summarises the research efforts in this area and highlights why a plant system is considered a necessary alternative production platform for high-tech subunit vaccines.

Spotlight on quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine(Gardasil®) in the prevention of premalignant genital lesions, genital cancer, and genital warts in women

Quadrivalent human papilloma virus (HPV) [types 6, 11, 16, 18] recombinant vaccine (Gardasil®; Silgard®) is composed of virus-like particles (VLPs) formed by self-assembly of recombinant L1 capsid protein from each of HPV types 6, 11, 16, and 18. The VLPs are noninfectious, containing no DNA, and are highly immunogenic, inducing high levels of neutralizing antibodies against the particular HPV types when administered to animals or humans. Quadrivalent HPV vaccine is indicated for use from the age of 9 years for the prevention of premalignant genital lesions (cervical, vulvar, and vaginal), cervical cancer, and external genital warts (condyloma acuminata) causally related to certain oncogenic or specific HPV types. In placebo-controlled clinical trials, quadrivalent HPV vaccine administered as three doses over 6 months provided high-level protection against infection or disease caused by the vaccine HPV types over 2-4 years of follow-up in females aged 15-45 years who were naive to the vaccine HPV types. A degree of cross-protection against certain other non-vaccine high-risk HPV types was also observed. The vaccine is not effective against current infection with a vaccine HPV type. Girls or women with current infection with one or more of the vaccine HPV types gained protection from infection or disease caused by the remaining vaccine HPV types and they were also protected against reinfection with the same HPV type after clearance of an infection caused by a vaccine HPV type. High seroconversion rates and high levels of anti-HPV antibodies were observed in all vaccinated individuals of all age ranges from 9 to 45 years. No correlation was found between antibody levels and protective efficacy of the vaccine. Rechallenge with quadrivalent HPV vaccine produced a potent anamnestic humoral immune response. The vaccine is generally well tolerated and is projected to be cost effective in most pharmacoeconomic models. Therefore, quadrivalent HPV vaccine offers an effective means, in combination with screening programs, to substantially reduce the burden of HPV-related precancerous lesions and cancer, particularly cervical cancer, as well as anogenital warts.

Effect of the human papillomavirus (HPV) quadrivalent vaccine in a subgroup of women with cervical and vulvar disease: retrospective pooled analysis of trial data

OBJECTIVES

To determine the effect of human papillomavirus (HPV) quadrivalent vaccine on the risk of developing subsequent disease after an excisional procedure for cervical intraepithelial neoplasia or diagnosis of genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia.

DESIGN

Retrospective analysis of data from two international, double blind, placebo controlled, randomised efficacy trials of quadrivalent HPV vaccine (protocol 013 (FUTURE I) and protocol 015 (FUTURE II)).

SETTING

Primary care centres and university or hospital associated health centres in 24 countries and territories around the world.

PARTICIPANTS

Among 17,622 women aged 15-26 years who underwent 1:1 randomisation to vaccine or placebo, 2054 received cervical surgery or were diagnosed with genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia.

INTERVENTION

Three doses of quadrivalent HPV vaccine or placebo at day 1, month 2, and month 6.

MAIN OUTCOME MEASURES

Incidence of HPV related disease from 60 days after treatment or diagnosis, expressed as the number of women with an end point per 100 person years at risk.

RESULTS

A total of 587 vaccine and 763 placebo recipients underwent cervical surgery. The incidence of any subsequent HPV related disease was 6.6 and 12.2 in vaccine and placebo recipients respectively (46.2% reduction (95% confidence interval 22.5% to 63.2%) with vaccination). Vaccination was associated with a significant reduction in risk of any subsequent high grade disease of the cervix by 64.9% (20.1% to 86.3%). A total of 229 vaccine recipients and 475 placebo recipients were diagnosed with genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia, and the incidence of any subsequent HPV related disease was 20.1 and 31.0 in vaccine and placebo recipients respectively (35.2% reduction (13.8% to 51.8%)).

CONCLUSIONS

Previous vaccination with quadrivalent HPV vaccine among women who had surgical treatment for HPV related disease significantly reduced the incidence of subsequent HPV related disease, including high grade disease.

TRIAL REGISTRATIONS

NCT00092521 and NCT00092534.

Randomized trial of HPV4 vaccine assessing the response to HPV4 vaccine in two schedules among Peruvian female sex workers

Two hundred female sex workers (FSWs) in Lima, Peru were randomized to receive HPV4 vaccine in the standard (0, 2, 6 months) or a modified schedule (0, 3, 6 months). One hundred and eighty four (92%) participants completed 3 doses of vaccine. Baseline seropositive rates were 58% for HPV6, 22.5% for HPV11, 41.5% for HPV16, and 13% for HPV18. The final geometric mean antibody titer (GMT) following vaccination was significantly greater for women who were seropositive at baseline compared to seronegative women: HPV6 (GMT ratio=2.3, p<0.01), HPV11 (GMT ratio=2.7, p<0.01), HPV16 (GMT ratio=1.3, p=0.04), and HPV18 (GMT ratio=2.4, p<0.01). Antibody titers in the modified schedule were not inferior to those in the standard schedule, suggesting the modified schedule may be paired with required STD visits. Although all women benefit from vaccination, administration at a younger age and before sexual debut is needed to achieve maximum protection from vaccine.

NCI, NHLBI/PBMTC first international conference on late effects after pediatric hematopoietic cell transplantation: persistent immune deficiency in pediatric transplant survivors

Defective immune reconstitution is a major barrier to successful hematopoietic cell transplantation (HCT), and has important implications in the pediatric population. There are many factors that affect immune recovery, including stem cell source and graft-versus-host disease (GVHD). Complete assessment of immune recovery, including T and B lymphocyte evaluation, innate immunity, and response to neoantigens, may provide insight as to infection risk and optimal time for immunizations. The increasing use of cord blood grafts requires additional study regarding early reconstitution and impact upon survival. Immunization schedules may require modification based upon stem cell source and immune reconstitution, and this is of particular importance as many children have been incompletely immunized, or not at all, before school entry. Additional studies are needed in children post-HCT to evaluate the impact of differing stem cell sources upon immune reconstitution, infectious risks, and immunization responses.

Evidence of immune memory 8.5 years following administration of a prophylactic human papillomavirus type 16 vaccine

BACKGROUND

The duration of protection conferred by prophylactic human papillomavirus (HPV) L1 virus-like particle vaccines is a critical determinant of their public health impact. A feature of vaccines that confer long-term immunity is their ability to induce immune memory.

OBJECTIVES

We evaluated antibody responses against HPV types 6, 11, 16 and 18 following administration of the quadrivalent HPV-6/11/16/18 vaccine to women who had previously received a monovalent HPV-16 vaccine.

STUDY DESIGN

As part of an extended follow-up study conducted between 2006 and 2009 in Seattle, Washington, we administered the quadrivalent HPV-6/11/16/18 vaccine to 52 women (19 vaccine and 33 placebo recipients) who had participated in a monovalent HPV-16 vaccine trial 8.5 years earlier. Serum samples were tested for anti-HPV antibodies using competitive Luminex immunoassay.

RESULTS

Following administration of the first dose of the quadrivalent HPV-6/11/16/18 vaccine, the anti-HPV-16 geometric mean titer among monovalent HPV-16 vaccine recipients (GMT=5024.0 milli-Merck units per milliliter [mMU/mL]; 95% confidence interval [CI]: 2710.1, 9313.6 mMU/mL) substantially exceeded that among the placebo recipients (GMT=136.1; 95% CI: 78.5, 235.8 mMU/mL; p<0.01) and their own highest anti-HPV-16 response observed during the original trial (GMT at month 7 of the original trial=1552.7 mMU/mL; 95% CI: 1072.6, 2247.7 mMU/mL; p<0.01).

CONCLUSIONS

The findings suggest that the administration of the three-dose regimen of the monovalent HPV-16 vaccine had produced memory lymphocytes, characterized by a heightened immune response following administration of the quadrivalent HPV-6/11/16/18 vaccine that effectively served as an antigen challenge.

Prevalent serum antibody is not a marker of immune protection against acquisition of oncogenic HPV16 in men

In women, naturally induced anti-human papilloma virus (HPV) serum antibodies are a likely marker of host immune protection against subsequent HPV acquisition and progression to precancerous lesions and cancers. However, it is unclear whether the same is the case in men. In this study, we assessed the risk of incident genital infection and 6-month persistent genital infection with HPV16 in relation to baseline serostatus in a cohort of 2,187 men over a 48-month period. Genital swabs were collected every 6 months and tested for HPV presence. Incidence proportions by serostatus were calculated at each study visit to examine whether potential immune protection attenuated over time. Overall, incidence proportions did not differ statistically between baseline seropositive and seronegative men at any study visit or over the follow-up period. The risk of incident and 6-month persistent infection was not associated with baseline serostatus or baseline serum antibody levels in the cohort. Our findings suggest that baseline HPV seropositivity in men is not associated with reduced risk of subsequent HPV16 acquisition. Thus, prevalent serum antibodies induced by prior infection may not be a suitable marker for subsequent immune protection against genital HPV16 acquisition in men.

The efficacy and safety of the quadrivalent human papillomavirus 6/11/16/18 vaccine gardasil

Human papillomavirus (HPV) infection causes cervical cancer, a significant portion of anal, genital, and oropharyngeal cancers, genital warts, and recurrent respiratory papillomatosis. In June 2006, a quadrivalent HPV-6/11/16/18 vaccine (Gardasil/Silgard) was licensed in the United States, and subsequently in the European Union (September 2006). It has since been approved in 121 countries, with >74 million doses distributed globally as of March 2011. As the incidence of HPV infection peaks 5-10 years after the onset of sexual activity, preadolescents and adolescents represent an appropriate target group to implement HPV vaccination programs so as to achieve the maximal public health benefit. In this article, we provide an overview of the prophylactic efficacy of the vaccine in young women who were found to be negative to at least one of the four vaccine HPV types, thus approximating sexually naive adolescents. Because adolescents are also at high risk for other infections which are preventable by currently available vaccines, the development of concurrent immunization strategies may lead to better compliance, thereby contributing to the overall goal of protection against preventable diseases. We also summarize concomitant administration studies with meningococcal, diphtheria, tetanus, and pertussis vaccines, which were conducted in adolescents aged 9-15 years. Prophylactic efficacy in other populations (males aged 16-26 years) is also summarized along with long-term safety and efficacy studies.

Clinical perspectives on the role of the human papillomavirus vaccine in the prevention of cancer

The role of human papillomavirus (HPV) in the genesis of cervical cancer has been well documented, and an increasing body of literature exists with regard to the role of HPV in other cancers, including cancers of the head and neck. With the recent expansion of the United States Food and Drug Administration's approval of the quadrivalent HPV virus-like particle vaccine to include men and boys and approval of the bivalent vaccine this year, the controversies regarding who should be vaccinated, at what age is vaccination most appropriate, and the limitations of the available HPV vaccines are increasing. Health care providers are challenged with evaluating the current, but continually changing, clinical evidence when making critical decisions for their patients. A literature search of MEDLINE and SciVerse Scopus was conducted for articles published from 1998-April 2010 regarding HPV, HPV-related cancers, and HPV vaccines. Although both HPV vaccines were greater than 90% effective in the prevention of cervical cancer precursors in an according-to-protocol cohort, both vaccines were significantly less effective in the intent-to-treat population. In patients who achieved seroconversion, the geometric mean titers decrease dramatically within the first 2 years after vaccination, and then continue to decline at a slower rate. No effective antibody titer has been defined for either vaccine, and no studies have been conducted with documented HPV exposure after vaccination. With low efficacy rates in an intent-to-treat population and the potential for waning immunity, it is imperative for women to continue to receive regular Pap tests and gynecologic examinations. Although vaccine administration was shown to be cost-effective when administered to adolescent girls, many of these simulations overestimated the durability of protection, efficacy rates in sexually active women, impact of incomplete vaccination, or necessity of boosters in the future. Whereas the introduction of the HPV vaccine was an enormous advancement in the cancer prevention research arena, optimization of its clinical use is still needed.

Neutralization of non-vaccine human papillomavirus pseudoviruses from the A7 and A9 species groups by bivalent HPV vaccine sera

The majority of cervical cancers are associated with infection by one or more Human Papillomavirus (HPV) types from just two distinct Alpha-Papillomavirus species groups, A7 and A9. The extent to which the current HPV16/18 vaccines will protect against other genetically related HPV types is of interest to inform vaccine implementation, cervical disease surveillance and the development of second generation HPV vaccines. The aim of this study was to determine the frequency and titer of neutralizing antibodies against a range of A7 (18, 39, 45, 59, 68) and A9 (16, 31, 33, 35, 52, 58) HPV types using sera from individuals immunized with the bivalent HPV vaccine within the school-based, UK national HPV immunization programme. Serum samples were collected from 69 girls aged 13–14 years, a median 5.9 months (inter-quartile range, IQR, 5.7–6.0) after their third vaccine dose. Cross-neutralizing antibodies against HPV31, HPV33, HPV35 and HPV45 were common and strongly associated with the titer for the related vaccine-type, but were considerably lower (<1%) than their related vaccine type-specific response. The low prevalence of these HPV types in the population and the ages within the study cohort suggest these responses are due to vaccination. It is unclear whether such low levels of neutralizing antibodies would be sufficient to protect at the site of infection in the absence of other immune effectors but the coincidence with HPV types reported from efficacy studies is intriguing. The utility of neutralizing antibodies as surrogate markers of protection remains to be determined.

Role and uptake of human papillomavirus vaccine in adolescent health in the United States

Both the prophylactic human papillomavirus (HPV) vaccines, Gardasil^® and Cervarix^®, are licensed for the prevention of cervical cancer in females, and Gardasil is also licensed for the prevention of genital warts and anal cancer in both males and females. This review focuses on the uptake of these vaccines in adolescent males and females in the USA and the barriers associated with vaccine initiation and completion. In the USA in 2009, approximately 44.3% of adolescent females aged 13-17 years had received at least one dose of the HPV vaccine, but only 26.7% had received all three doses. In general, the Northeast and Midwest regions of the USA have the highest rates of HPV vaccine initiation in adolescent females, while the Southeast has the lowest rates of vaccine initiation. Uptake of the first dose of the HPV vaccine in adolescent females did not vary by race/ethnicity; however, completion of all three doses is lower among African Americans (23.1%) and Latinos (23.4%) compared with Caucasians (29.3%). At present, vaccination rates among adolescent females are lower than expected, and thus vaccine models suggest that it is more cost-effective to vaccinate both adolescent males and females. Current guidelines for HPV vaccination in adolescent males is recommended only for "permissive use," which leaves this population out of routine vaccination for HPV. The uptake of the vaccine is challenged by the high cost, feasibility, and logistics of three-dose deliveries. The biggest impact on acceptability of the vaccine is by adolescents, physicians, parents, and the community. Future efforts need to focus on HPV vaccine education among adolescents and decreasing the barriers associated with poor vaccine uptake and completion in adolescents before their sexual debut, but Papanicolau screening should remain routine among adults and those already infected until a therapeutic vaccine can be developed.

Immunization of hematopoietic stem cell transplant recipients against vaccine-preventable diseases

Worldwide, over 40,000 hematopoietic cell transplants (HCT) are carried out each year, with the majority of patients surviving long term. Owing to their new immune systems, these patients are susceptible to a variety of preventable infectious diseases. The 2009 influenza pandemic, the increase in pertussis and antibiotic-resistant pneumococcus, as well as recent outbreaks of measles and mumps in immunocompetent individuals further highlight the need for effective revaccination of HCT recipients. Post-transplant vaccine guidelines, including those published in 2009, recommend immunization of all patient groups at fixed times post-HCT. Although early vaccination to protect against vaccine-preventable diseases is desirable, there are still limited data on whether this approach is efficacious in patient groups whose immune recovery differs from recipients of an unmodified HLA-matched sibling transplant. In the absence of such data, prospective trials are needed to better define the optimal timing for immunizing recipients of alternative donors. Ideally, such trials should be designed to identify biological markers that will predict an optimal and durable vaccine response.

Aspects of prophylactic vaccination against cervical cancer and other human papillomavirus-related cancers in developing countries

Cervical cancer and other human papillomavirus- (HPV-) related cancers are preventable, but preventive measures implemented in developing countries and especially in low-income rural regions have not been effective. Cervical cancer burden derived from sexually transmitted HPV infections is the heaviest in developing countries, and a dramatic increase in the number of cervical cancer cases is predicted, if no intervention is implemented in the near future. HPV vaccines offer an efficient way to prevent related cancers. Recently implemented school-based HPV vaccination demonstration programmes can help tackle the challenges linked with vaccine coverage, and access to vaccination and health services, but prevention strategies need to be modified according to regional characteristics. In urban regions WHO-recommended vaccination strategies might be enough to significantly reduce HPV-related disease burden, but in the rural regions additional vaccination strategies, vaccinating both sexes rather than only females when school attendance is the highest and applying a two-dose regime, need to be considered. From the point of view of both public health and ethics identification of the most effective prevention strategies is pivotal, especially when access to health services is limited. Considering cost-effectiveness versus justice further research on optional vaccination strategies is warranted.

Human papillomavirus type 16 variant analysis of E6, E7, and L1 [corrected] genes and long control region in [corrected] cervical carcinomas in patients in northeast China

Human papillomavirus type 16 (HPV 16) plays a cardinal role in the pathogenesis of cervical cancer. HPV 16 has intratypic variants which show different geographical distributions and different oncogenic potentials. To analyze the presence of sequence variations of HPV 16 variants in northeast China, 71 cervical carcinomas were identified by HPV typing. HPV 16-positive specimens were analyzed by PCR-directed sequencing in the E6, E7, and L1 genes and the LCR (long control region). The variation data were compared with those of neighboring districts. In this hospital-based study, HPV 16 was the most common type (73.24%). In HPV 16-positive specimens, 67.31% belonged to the European (E) lineage, while 32.69% were Asian (As) variants. The Asian-American (AA), African-1 (Af-1), African-2 (Af-2), and northern American (NA) lineages were not detected. The most frequently observed variation sites were T178G (32.69%) in E6; A647G (34.62%), G666A (38.46%), and T846C (32.69%) in E7; C6826T (36.17%) and G7060A (61.70%) in L1; and G7521A (98.08%) in the LCR. The most prevalent amino acid variations were D25E in E6 and N29S in E7. In addition, 28 novel variations of HPV 16 were reported. Some covariations between different genes were obtained. In this study, HPV 16 variants belonged to the European lineage and the Asian lineage. Compared with neighboring districts, the distribution of HPV 16 variants in northeast China had a typical pattern. As the first report on HPV 16 variants in northeast China, it should be helpful for designing a HPV vaccine and HPV vaccination program in China.

Lack of type-specific concordance between human papillomavirus (HPV) serology and HPV DNA detection in the uterine cervix and oral mucosa

There is limited knowledge about longitudinal genotype-specific concordance between human papillomavirus (HPV) serology and co-existent presence of HPV DNA in the uterine cervix. The role of oral HPV infections in inducing serological response is unclear, as is the effect of HPV antibodies on the outcome of oral HPV infections. The present study is part of the Finnish Family HPV Study designed to evaluate dynamics of HPV infections within families. Here, we correlated the point prevalence of HPV6, 11, 16, 18 and 45 antibodies and concomitant genotype-specific HPV DNA detection in cervical and oral samples of 323 mothers during their 3 year (mean 37.5 months) follow-up. The mean age of these pregnant mothers at enrolment (third trimester) was 25.5 years. HPV antibodies were analysed with multiplex HPV serology and HPV genotyping was performed using a Multimetrix kit (Progen Biotechnik). There was no concordance between cervical DNA detection and co-existent seropositivity, and the same was true even in samples taken 12 months apart. Women who cleared their cervical HPV16 infection had the highest HPV16 antibody levels, whereas those who acquired incident HPV16 infections had the lowest antibody levels. Neither the presence nor the dynamics of oral HPV DNA had any correlation with HPV serology.

Diversity and uncommon HPV types in HIV seropositive and seronegative women attending an STI clinic

Given the causal relationship between specific types of HPV with cervical cancer and precursor lesions, it is important to identify the viral type involved. The aim of this study is to access the prevalence of HPV types in HIV seropositive and seronegative women. Accordingly, 77 HPV positive cervical samples were obtained from 284 women (seropositive (n=112) and seronegative (n=172) for HIV) who attended a Sexually Transmitted Infection clinic, in Vitoria, Southeastern Brazil. Viral DNA was amplified by PCR using MY09/MY11 degenerated primers and the genotyping was performed by Restriction Fragment Length Polymorphism. Seventy five out of the 77 HPV samples were genotyped: 6, 11, 13, 16, 18, 26, 31, 31b, 32, 33, 34, 35, 52, 53, 55, 56, 58, 59, 61, 62, 64, 66, 71, 81, 83, 84. The most prevalent type was HPV16 followed by HPV types 6, 11 and 53. Fifty five percent and 45% belonged to high and low risk types, respectively. High risk types corresponded to 59% and 54.5% of the HPV detected in HIV seronegative and seropositive women, respectively. The uncommon HPV 13 type in cervical samples was also observed in this study. The oncogenic types were more common in the HIV seronegative samples and the number of cases with multiple infections was similar for the two groups. HPV typing is not only important clinically for the establishment of monitoring and treatment of a patient, it also provides knowledge of the viral types circulating in a population, which is of interest in the development of prevention and treatment programs for this disease.

Impact of an HPV6/11/16/18 L1 virus-like particle vaccine on progression to cervical intraepithelial neoplasia in seropositive women with HPV16/18 infection

The impact of a human papillomavirus (HPV) vaccine on development of cervical intraepithelial neoplasia grade 2-3 or adenocarcinoma in situ (CIN2-3/AIS) in women with ongoing HPV16 or 18 infections prevaccination is reported. Seventeen thousand six-hundred and twenty-two women aged 16-26 were enrolled in 1 of 2 randomized, placebo-controlled, efficacy trials (Protocols 013 and 015). Vaccine or placebo was given at day 1, month 2 and 6. Women were tested for HPV6/11/16/18 DNA and antibodies at day 1. We focus on the subset of women who were seropositive and DNA positive to HPV16 or HPV18 prevaccination. Incidence is expressed as the number of women with an endpoint per 100 person-years-at-risk. In total, 419 vaccine and 446 placebo recipients were both seropositive and DNA positive to HPV16 or HPV18 prevaccination and had at least one follow-up visit. In Protocol 013, the incidence of HPV16/18-related CIN2-3/AIS among these women was 10.9 in the vaccine arm and 7.0 in the placebo arm (vaccine efficacy = -54.9; 95% CI: -181.7, 13.0). In Protocol 015, the incidence of HPV16/18-related CIN2-3/AIS was 5.5 in the vaccine arm and 6.2 in the placebo arm (vaccine efficacy = 12.2%; 95% CI: -29.8, 40.9). These data suggest HPV vaccination neither reduces nor enhances progression to HPV16/18-related high grade cervical lesions, and cervical cytology screening and corresponding management should continue as per local recommendations. Ultimately, population-based surveillance of vaccinated individuals beyond these clinical trials will be required to further address questions regarding the impact of vaccination in women exposed to vaccine HPV types before vaccination.

Prevalence and type distribution of human papillomavirus in healthy Japanese women aged 20 to 25 years old enrolled in a clinical study

Efficacy, immunogenicity and tolerability of the human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine were evaluated in Japanese women aged 20-25 years, for which results have been reported previously. We analyzed the baseline data from that study and report the prevalence rates of HPV infection in young healthy Japanese women. One thousand and the forty Japanese women aged 20-25 years were enrolled in a phase II, double-blind, controlled, randomized, multicenter study. At study entry, cervical specimens were collected from the women and tested by line probe assay for 25 HPV-types and by HPV-16/18-specific polymerase chain reaction. The most frequently detected HPV-type in baseline cervical specimens was HPV-52 (8.1%), followed by HPV-16 (6.5%), HPV-51 (4.5%), HPV-18 (4.0%) and HPV-31 (3.8%). The proportion of HPV DNA-positive women increased with severity of cytological abnormalities: 26.1% (237/908) in normal cytology, 93.3% (70/75) in low-grade squamous intraepithelial lesion and 100% (7/7) in high-grade squamous intraepithelial lesion. The relative contribution of HPV-16 and HPV-18 was 4.1 and 3.0% for normal cytology cases, and 20.0 and 16.0% in low-grade squamous intraepithelial lesion, respectively. HPV-16 was found in four of seven high-grade squamous intraepithelial lesion cases (57.1%) and five of the six cervical intraepithelial neoplasia 2+ cases (83.3%). Multiple and single HPV infections were observed in 13.5% (140/1039) and 20.7% (215/1039) of all women, respectively. The HPV prevalence rates in Japanese women aged 20-25 years underline the importance of HPV vaccination at a young age and this report should be useful for monitoring changes in HPV prevalence after widespread HPV vaccination in Japanese women.

Cost-effectiveness of different human papillomavirus vaccines in Singapore

Background

Human papillomavirus (HPV) vaccines are widely available and there have been studies exploring their potential clinical impact and cost-effectiveness. However, few studies have compared the cost-effectiveness among the 2 main vaccines available - a bivalent vaccine against HPV 16/18, and a quadrivalent vaccine against 6/11/16/18. We explore the cost-effectiveness of these two HPV vaccines in tropical Singapore.

Methods

We developed a Markov state-transition model to represent the natural history of cervical cancer to predict HPV infection, cancer incidence, mortality, and costs. Cytologic screening and treatment of different outcomes of HPV infection were incorporated. Vaccination was provided to a cohort of 12-year old females in Singapore, followed up until death. Based on available vaccines on the market, the bivalent vaccine had increased effectiveness against a wider range of HPV types, while the quadrivalent vaccine had effectiveness against genital warts. Incremental cost-effectiveness ratios (ICER) compared vaccination to no-vaccination, and between the two vaccines. Sensitivity analyses explored differences in vaccine effectiveness and uptake, and other key input parameters.

Results

For the no vaccination scenario, 229 cervical cancer cases occurred over the cohort's lifetime. The total discounted cost per individual due to HPV infection was SGD$275 with 28.54 discounted life-years. With 100% vaccine coverage, the quadrivalent vaccine reduced cancers by 176, and had an ICER of SGD$12,866 per life-year saved. For the bivalent vaccine, 197 cancers were prevented with an ICER of $12,827 per life-year saved. Comparing the bivalent to the quadrivalent vaccine, the ICER was $12,488 per life-year saved. However, the cost per QALY saved for the quadrivalent vaccine compared to no vaccine was $9,071, while it was $10,392 for the bivalent vaccine, with the quadrivalent vaccine dominating the bivalent vaccine due to the additional QALY effect from reduction in genital warts. The overall outcomes were most sensitive to vaccine cost and coverage.

Conclusion

HPV vaccination is a cost-effective strategy, and should be considered a possible strategy to reduce the impact of HPV infection.

The breadth and potency of passively acquired human immunodeficiency virus type 1-specific neutralizing antibodies do not correlate with the risk of infant infection

Although a major goal of human immunodeficiency virus type 1 (HIV-1) vaccine efforts is to elicit broad and potent neutralizing antibodies (NAbs), there are no data that directly demonstrate a role for such NAbs in protection from HIV-1 infection in exposed humans. The setting of mother-to-child transmission provides an opportunity to examine whether NAbs provide protection from HIV-1 infection because infants acquire passive antibodies from their mothers prior to exposure to HIV-1 through breastfeeding. We evaluated the characteristics of HIV-1-specific NAbs in 100 breast-fed infants of HIV-1-positive mothers who were HIV-1 negative at birth and monitored them until age 2. A panel of eight viruses that included variants representative of those in the study region as well as more diverse strains was used to determine the breadth of the infant NAbs. From their mothers, infants acquired broad and potent NAbs that were capable of recognizing heterologous circulating HIV-1 variants of diverse subtypes, but the presence of NAbs of broad HIV-1 specificity was not associated with transmission risk. There was also no correlation between responses to any particular virus tested, which included a range of diverse variants that demonstrated different neutralization profiles, including recognition by specific antibodies with known epitope targets. The eight viruses tested exhibited neutralization profiles to a variety of monoclonal antibodies (2F5, PG9, and VRC01) similar to those of viruses present in pregnant women in the cohort. These results suggest that the breadth and potency of the heterologous antibody response in exposed infants, measured against a virus panel comprised of variants typical of those circulating in the population, does not predict protection.

Quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine (Gardasil®): a review of its use in the prevention of premalignant genital lesions, genital cancer and genital warts in women

Quadrivalent human papilloma virus (HPV) [types 6, 11, 16, 18] recombinant vaccine (Gardasil®; Silgard®) is composed of virus-like particles (VLPs) formed by self-assembly of recombinant L1 capsid protein from each of HPV types 6, 11, 16 and 18. The VLPs are noninfectious, containing no DNA, and are highly immunogenic, inducing high levels of neutralizing antibodies against the particular HPV types when administered to animals or humans. Quadrivalent HPV vaccine is indicated for use from the age of 9 years for the prevention of premalignant genital lesions (cervical, vulvar and vaginal), cervical cancer and external genital warts (condyloma acuminata) causally related to certain oncogenic or specific HPV types. In placebo-controlled clinical trials, quadrivalent HPV vaccine administered as three doses over 6 months provided high-level protection against infection or disease caused by the vaccine HPV types over 2-4 years of follow-up in females aged 15-45 years who were naive to the vaccine HPV types. A degree of cross-protection against certain other non-vaccine high-risk HPV types was also observed. The vaccine is not effective against current infection with a vaccine HPV type. Girls or women with current infection with one or more of the vaccine HPV types gained protection from infection or disease caused by the remaining vaccine HPV types and they were also protected against reinfection with the same HPV type after clearance of an infection caused by a vaccine HPV type. High seroconversion rates and high levels of anti-HPV antibodies were observed in all vaccinated individuals of all age ranges from 9 to 45 years. No correlation was found between antibody levels and protective efficacy of the vaccine. Rechallenge with quadrivalent HPV vaccine produced a potent anamnestic humoral immune response. The vaccine is generally well tolerated and is projected to be cost effective in most pharmacoeconomic models. Therefore, quadrivalent HPV vaccine offers an effective means, in combination with screening programmes, to substantially reduce the burden of HPV-related precancerous lesions and cancer, particularly cervical cancer, as well as anogenital warts.

Position paper--HPV and the primary prevention of cancer; improving vaccine uptake by paediatricians

A large proportion of sexually active adults are infected with the human papillomaviruses (HPVs). Although largely asymptomatic, some types of HPVs (HPV-16, HPV-18) which infect the genitalia are known to cause cancers, including cervical cancer. Cervical cancer is an important public health concern and is the second most clinically important cancer to breast cancer in women aged 15-44 years. Until recently, cervical cancer strategies focussed on screening. However, as adolescents become sexually active at a much younger age, the focus is on the use of vaccination as an effective measure to prevent progression of HPV infection to cancer. HPV is also involved in the aetiology of cancers of the anus, vagina, vulva and penis as well as genital warts and laryngeal papillomatosis in young children. Primary prevention through vaccination is now possible in Europe using either the quadrivalent HPV vaccine, Gardasil® (Sanofi Pasteur MSD), or the bivalent HPV vaccine, Cervarix® (GSK), which are both highly immunogenic, with their effects persisting for at least 5 years. HPV vaccines are well tolerated, with serious vaccine-related events occurring in less than 0.1% of patients for both vaccines. Here, we review the possibilities for utilising vaccination programmes alongside current cervical cancer screening in comprehensive cervical cancer prevention programmes. The European Academy of Paediatrics Scientific Working Group on Vaccination concluded that the use of HPV vaccines will have a significant impact in primary prevention of cancers and other HPV-related disease.