Global evaluation of lineage-specific human papillomavirus capsid antigenicity using antibodies elicited by natural infection.

Human Papillomavirus (HPV) type variants have been classified into lineages and sublineages based upon their whole genome sequence. Here we have examined the specificity of antibodies generated following natural infection with lineage variants of oncogenic types (HPV16, 18, 31, 33, 45, 52 and 58) by testing serum samples assembled from existing archives from women residing in Africa, The Americas, Asia or Europe against representative lineage-specific pseudoviruses for each genotype. We have subjected the resulting neutralizing antibody data to antigenic clustering methods and created relational antigenic profiles for each genotype to inform the delineation of lineage-specific serotypes. For most genotypes, there was evidence of differential recognition of lineage-specific antigens and in some cases of a sufficient magnitude to suggest that some lineages should be considered antigenically distinct within their respective genotypes. These data provide compelling evidence for a degree of lineage specificity within the humoral immune response following natural infection with oncogenic HPV.

The impact of over ten years of HPV vaccination in England: Surveillance of type-specific HPV in young sexually active females.

INTRODUCTION: The UK national human papillomavirus (HPV) vaccination programme was introduced in 2008 using the bivalent HPV16/18 vaccine, changing to the quadrivalent HPV6/11/16/18 vaccine from 2012. We provide an analysis of type-specific HPV prevalence in young sexually active females in England to end 2020 (when the first routinely HPV vaccinated females were reaching 25 years of age and entering the National Health Service Cervical Screening Programme), showing the impact of over ten years of high coverage HPV vaccination. METHODS: Residual vulvovaginal swabs (VVS) were collected from 16 to 24 year old women attending for chlamydia screening between 2010 and 2020, anonymised and tested for type-specific HPV DNA. Trends in vaccine and non-vaccine HPV type prevalence were compared over time and association with vaccination coverage was evaluated within the post-vaccination period. RESULTS: A total of 21,168 eligible VVS specimens were tested for HPV DNA. The prevalence of HPV16/18 in sexually active 16-18 year old females who were offered vaccination aged 12-13 years was <1% in the most recent years tested, compared to over 15% prior to the vaccination programme in 2008. The magnitude of these decreases also suggests reduced transmission is offering some herd protection to unvaccinated females. HPV31/33/45 prevalence also steadily decreased, providing evidence of cross-protection. HPV6/11 prevalence remained stable during the bivalent vaccine period, with more recent declines, as expected due to the use of the quadrivalent vaccine. There has been no substantive increase in the prevalence of other high-risk (HR) HPV types. DISCUSSION: More than ten years of high coverage HPV vaccination in adolescent females in England has delivered dramatic declines in the prevalence of HPV vaccine-types and closely related HPV types in females in the vaccine eligible age group, and no indication of type replacement. These findings should enable confidence in planning for cervical screening of these females, and in predicting declines in HPV-related cancers.

Multiplex Human Papillomavirus L1L2 virus-like particle antibody binding assay.

A variety of in vitro techniques are available to estimate the level of antibodies present in human serum samples. Such tests are highly specific and are used to determine prior exposure to a pathogen or to estimate the magnitude, breadth and durability of individual and population level vaccine immunity. Multiplex (or multi-analyte) platforms are increasingly being used to evaluate immune responses against multiple antigens at the same time, usually at reduced per sample cost and a more efficient use of available samples. Consequently, multiplex serology is an essential component of a wide range of public health programmes. Human papillomavirus (HPV) serology is limited to a small number of academic, public health and vaccine manufacturer laboratories globally. Such platforms include indirect binding to the major (L1) capsid protein virus-like particles (VLP), monoclonal antibody competition against L1 VLP and indirect binding to L1 and L2 (minor capsid protein) VLP on multiplex (Luminex®, Meso Scale Discovery®) and standard (ELISA) platforms. The methodology described here utilizes a common multi-analyte platform and L1L2-based VLP expressed in house, which allows the simultaneous detection and quantification of antibody responses against nine vaccine-relevant HPV genotypes.

Contribution of Surface-Exposed Loops on the HPV16 Capsid to Antigenic Domains Recognized by Vaccine or Natural Infection Induced Neutralizing Antibodies.

Human papillomavirus (HPV) is the causative agent of cervical and other cancers and represents a significant global health burden. HPV vaccines demonstrate excellent efficacy in clinical trials and effectiveness in national immunization programmes against the most prevalent genotype, HPV16. It is unclear whether the greater protection conferred by vaccine-induced antibodies, compared to natural infection antibodies, is due to differences in antibody magnitude and/or specificity. We explore the contribution of the surface-exposed loops of the major capsid protein to antigenic domains recognized by vaccine and natural infection neutralizing antibodies. Chimeric pseudoviruses incorporating individual (BC, DE, EF, FG, HI) or combined (All: BC/DE/EF/FG/HI) loop swaps between the target (HPV16) and control (HPV35) genotypes were generated, purified by ultracentrifugation and characterized by SDS-PAGE and electron microscopy. Neutralizing antibody data were subjected to hierarchical clustering and outcomes modeled on the HPV16 capsomer crystal model. Vaccine antibodies exhibited an FG loop preference followed by the EF and HI loops while natural infection antibodies displayed a more diverse pattern, most frequently against the EF loop followed by BC and FG. Both vaccine and natural infection antibodies demonstrated a clear requirement for multiple loops. Crystal modeling of these neutralizing antibody patterns suggested natural infection antibodies typically target the outer rim of the capsomer while vaccine antibodies target the central ring around the capsomer lumen. Chimeric pseudoviruses are useful tools for probing vaccine and natural infection antibody specificity. These data add to the evidence base for the effectiveness of an important public health intervention. IMPORTANCE The human papillomavirus type 16 (HPV16) major virus coat (capsid) protein is a target for antibodies induced by both natural infection and vaccination. Vaccine-induced immunity is highly protective against HPV16-related infection and disease while natural infection associated immunity significantly less so. For this study, we created chimeric functional pseudoviruses based upon an antigenically distant HPV genotype (HPV35) resistant to HPV16-specific antibodies with inserted capsid surface fragments (external loops) from HPV16. By using these chimeric pseudoviruses in functional neutralization assays we were able to highlight specific and distinct areas on the capsid surface recognized by both natural infection and vaccine induced antibodies. These data improve our understanding of the difference between natural infection and vaccine induced HPV16-specific immunity.

Binding antibody levels to vaccine (HPV6/11/16/18) and non-vaccine (HPV31/33/45/52/58) HPV antigens up to 7 years following immunization with either Cervarix® or Gardasil® vaccine.

Human Papillomavirus (HPV) bivalent (Cervarix®) and quadrivalent (Gardasil®) vaccines demonstrate robust efficacy against vaccine types and cross-protection against related non-vaccine types. Here we evaluate the breadth, magnitude and durability of the vaccine-induced antibody response against vaccine (HPV6/11/16/18) and non-vaccine (HPV31/33/45/52/58) type antigens up to 7 years following vaccination of 12-15 year old girls in a three dose schedule and contrast these data with the levels of antibody typically seen in natural infection. Vaccine-type antibody levels waned over the 7-year follow up period but remained at least an order of magnitude above the typical antibody levels elicited by natural infection. Seropositivity to non-vaccine types remained high 7 years after initial vaccination, but antibody levels approached those typically generated following natural infection. Empirical data on the breadth, magnitude, specificity and durability of the immune response elicited by the HPV vaccines contribute to improving the evidence base supporting this important public health intervention.

Post-vaccination HPV seroprevalence among female sexual health clinic attenders in England.

BACKGROUND: The National HPV Immunisation Programme was introduced in England in September 2008 using the HPV16/18 bivalent vaccine. We conducted serological surveillance to explore vaccination coverage levels. We also conducted a case-control study to investigate a hypothesised cross-protective effect of the HPV16/18 vaccine against genital warts. METHODS: Residual serum specimens from 16 to 20 year-old women attending six specialist sexual health services (SSHS) between 2011 and 2015 in England were tested for antibodies against HPV16 and HPV18 using a virus-like particle (VLP)-based multiplex serology assay. Patients were classified as having vaccine-induced seropositivity if they were seropositive for both HPV types and either had high antibody levels for at least one HPV type, or moderately high levels for both HPV types. Differences in vaccine-induced seropositivity by patient characteristics were investigated using logistic regression. Vaccine-induced seropositivity was then compared for patients with genital warts (cases) and matched patients without (controls). RESULTS: Of 3,973 serum specimens collected, 3,870 (97.4%) had a valid result. The proportion of women with vaccine-induced seropositivity decreased with age (from 78.1% in 16-year-olds to 52.6% in 20-year-olds). Vaccine-induced seropositivity was lower among women born outside the UK, from more deprived areas and with a history of chlamydia diagnosis. A difference in uptake by ethnic group was also seen but this was largely confounded by differences in deprivation and country of birth. Among 537 cases and 1,515 controls, there was little evidence of a protective effect of the bivalent HPV vaccine against genital warts (adjusted odds ratio 0.93; 95% CI: 0.74-1.18). DISCUSSION: Vaccine-induced seropositivity in this high-risk population was in line with vaccination coverage in the general population although was lower in some at-risk sub-groups. This study does not provide evidence to support a cross-protective effect of the HPV16/18 vaccine against genital warts.

Human papillomavirus (HPV) vaccination and oropharyngeal HPV in ethnically diverse, sexually active adolescents: community-based cross-sectional study.

OBJECTIVES: Oropharyngeal squamous cell carcinoma is the most common human papillomavirus (HPV)-associated cancer in the UK, but little is known about the prevalence of oropharyngeal HPV in sexually active teenagers. We investigated reported HPV vaccination coverage (in females) and prevalence of oropharyngeal HPV in sexually active students attending six technical colleges in London, UK. METHODS: In 2017, we obtained mouthwash samples and questionnaires from male and female students taking part in the 'Test n Treat' chlamydia screening trial. Samples were subjected to HPV genotyping. RESULTS: Of 232 participants approached, 202 (87%) provided a mouthwash sample and questionnaire. Participants' median age was 17 years and 47% were male. Most (73%) were from black and minority ethnic groups, 64% gave a history of oral sex, 52% reported having a new sexual partner in the past 6 months, 33% smoked cigarettes, 5.9% had concurrent genitourinary Chlamydia trachomatis infection and 1.5% Neisseria gonorrhoeae and 5.0% were gay or bisexual. Only 47% (50/107) of females reported being vaccinated against HPV 16/18, of whom 74% had received ≥2 injections. HPV genotyping showed three mouthwash samples (1.5%, 95% CI 0.3% to 4.3%) were positive for possible high-risk human papillomavirus (HR-HPV), one (0.5%, 0.0% to 2.7%) for low-risk HPV 6/11, but none (0.0%, 0.0% to 1.8%) for HR-HPV. Four samples (2.0%, 0.5% to 5.0%) were positive for HPV16 using a HPV16 type-specific quantitative PCR, but these were at a very low copy number and considered essentially negative. CONCLUSIONS: Despite the high prevalence of oral sex and genitourinary chlamydia and low prevalence of HPV vaccination, the prevalence of oropharyngeal HR-HPV in these adolescents was negligible.

Performance of human papillomavirus DNA detection in residual specimens taken for Chlamydia trachomatis and Neisseria gonorrhoeae nucleic acid amplification testing in men who have sex with men.

OBJECTIVES: Rectal swab specimens, either alone or pooled with first-void urine (FVU) and pharyngeal swab specimens, are used to test for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection in men who have sex with men (MSM). Following introduction of human papillomavirus (HPV) vaccination for MSM attending UK sexual health services (SHSs), HPV testing of residual CT/NG test specimens has been proposed to monitor HPV prevalence in this population. Performance of HPV detection in such specimens has not been evaluated previously. METHODS: MSM attending a UK SHS provided three specimens: (1) rectal swab for CT/NG, (2) pooled rectal/pharyngeal/FVU specimen for CT/NG and (3) dedicated anal swab for HPV. Specimen 3 and residual material from specimens 1 and 2 were tested for type-specific HPV DNA. HPV detection was by an in-house multiplex PCR and luminex-based genotyping assay. RESULTS: A total of 129 MSM were recruited with a mean age of 38.1 years; 24% were HIV-positive. Of the 129 MSM, 92 (71%) had any type-specific HPV DNA in ≥1 specimen; 80 (62%) had high risk (HR) HPV. Of 123 participants with sufficient residual pooled and dedicated specimens, 70 (56.9%) had detectable HPV on both, and 40 (32.5%) were negative on both; overall concordance was 89% (95% CI 83% to 94%), and kappa statistic was 0.78 (95% CI 0.66 to 0.89). Pooled samples had a 4.1% (95% CI -1.9% to 10.0%) higher test positivity rate than dedicated samples.Of 125 participants with sufficient residual rectal and specimens, 74 (59.2%) had detectable HPV on both, and 36 (28.8%) were negative on both; overall concordance was 88% (95% CI 81% to 93%), and kappa statistic was 0.74 (95% CI 0.61 to 0.86). Residual rectal samples had 5.6% (95%CI -0.6% to 11.8%) higher test positivity than dedicated samples. CONCLUSIONS: We observed high concordance between the dedicated and residual STI test specimens. Our data support the strategy of testing residual specimens for HPV prevalence monitoring in MSM to evaluate the impact of the targeted vaccination programme.

HPV16 and HPV18 seropositivity and DNA detection among men who have sex with men: a cross-sectional study conducted in a sexual health clinic in London.

OBJECTIVES: Men who have sex with men (MSM) have an increased risk of human papillomavirus (HPV) infection and related diseases compared with men who have sex exclusively with women. From April 2018, there has been a phased roll-out of HPV vaccination offered to MSM aged up to 45 years old who are attending sexual health clinics and HIV clinics in England. The vaccine is most effective if delivered prior to HPV infection. We estimated the proportion of MSM with no current vaccine-type infection and no serological evidence of prior infection, in a study undertaken prior to vaccine introduction. METHODS: We conducted a cross-sectional study among 484 MSM aged 18-40 years old who attended a sexual health clinic in London between 2010 and 2012. We estimated the prevalence of current and past infection by testing for HPV DNA in anogenital samples and for serum antibodies to HPV16 and HPV18. RESULTS: The median age was 30 years (IQR 25-35). The prevalence of HPV16 and HPV18 DNA was 13.2% and 6.2%, respectively. Seropositivity for HPV16 and HPV18 was 28.5% and 17.1%, respectively, with 11.4% seropositive for both types. Seropositivity for the same HPV type was strongly associated with anogenital DNA detection. 279 MSM (57.6%) tested negative for both HPV16 and HPV18 serology and were DNA negative for these two types; only 5 MSM (1.0%) were seropositive and DNA positive for both HPV types. CONCLUSIONS: This is the first study to determine both the prevalence of HPV DNA in anogenital samples and HPV seroprevalence among MSM attending a sexual health clinic in the UK. Over half of MSM in this study had no evidence of a previous or current infection with either of the high-risk HPV types included in the quadrivalent vaccine, which supports the rationale for opportunistic HPV vaccination of MSM attending sexual health clinics.

Comprehensive Assessment of the Antigenic Impact of Human Papillomavirus Lineage Variation on Recognition by Neutralizing Monoclonal Antibodies Raised against Lineage A Major Capsid Proteins of Vaccine-Related Genotypes.

Human papillomavirus (HPV) is the causative agent of cervical and other epithelial cancers. Naturally occurring variants of HPV have been classified into lineages and sublineages based on their whole-genome sequences, but little is known about the impact of this diversity on the structure and function of viral gene products. The HPV capsid is an icosahedral lattice comprising 72 pentamers of the major capsid protein (L1) and the associated minor capsid protein (L2). We investigated the potential impact of this genome variation on the capsid antigenicity of lineage and sublineage variants of seven vaccine-relevant, oncogenic HPV genotypes by using a large panel of monoclonal antibodies (MAbs) raised against the L1 proteins of lineage A antigens. Each genotype had at least one variant that displayed a ≥4-fold reduced neutralizing antibody sensitivity against at least one MAb, demonstrating that naturally occurring variation can affect one or more functional antigenic determinants on the HPV capsid. For HPV16, HPV18, HPV31, and HPV45, the overall impact was of a low magnitude. For HPV33 (sublineages A2 and A3 and lineages B and C), HPV52 (lineage D), and HPV58 (lineage C), however, variant residues in the indicated lineages and sublineages reduced their sensitivity to neutralization by all MAbs by up to 1,000-fold, suggesting the presence of key antigenic determinants on the surface of these capsids. These determinants were resolved further by site-directed mutagenesis. These data improve our understanding of the impact of naturally occurring variation on the antigenicity of the HPV capsid of vaccine-relevant oncogenic HPV genotypes.IMPORTANCE Human papillomavirus (HPV) is the causative agent of cervical and some other epithelial cancers. HPV vaccines generate functional (neutralizing) antibodies that target the virus particles (or capsids) of the most common HPV cancer-causing genotypes. Each genotype comprises variant forms that have arisen over millennia and which include changes within the capsid proteins. In this study, we explored the potential for these naturally occurring variant capsids to impact recognition by neutralizing monoclonal antibodies. All genotypes included at least one variant form that exhibited reduced recognition by at least one antibody, with some genotypes affected more than others. These data highlight the impact of naturally occurring variation on the structure of the HPV capsid proteins of vaccine-relevant oncogenic HPV genotypes.

Antimicrobial resistance in Mycoplasma genitalium sampled from the British general population.

BACKGROUND: Mycoplasma genitalium is a common sexually transmitted infection. Treatment guidelines focus on those with symptoms and sexual contacts, generally with regimens including doxycycline and/or azithromycin as first-line and moxifloxacin as second-line treatment. We investigated the prevalence of antimicrobial resistance (AMR)-conferring mutations in M. genitalium among the sexually-active British general population. METHODS: The third national survey of sexual attitudes and lifestyles (Natsal-3) is a probability sample survey of 15 162 men and women aged 16-74 years in Britain conducted during 2010-12. Urine test results for M. genitalium were available for 4507 participants aged 16-44 years reporting >1 lifetime sexual partner. In this study, we sequenced regions of the 23S rRNA and parC genes to detect known genotypic determinants for resistance to macrolides and fluoroquinolones respectively. RESULTS: 94% (66/70) of specimens were re-confirmed as M. genitalium positive, with successful sequencing in 85% (56/66) for 23S rRNA and 92% (61/66) for parC genes. Mutations in 23S rRNA gene (position A2058/A2059) were detected in 16.1% (95%CI: 8.6% to 27.8%) and in parC (encoding ParC D87N/D87Y) in 3.3% (0.9%-11.2%). Macrolide resistance was more likely in participants reporting STI diagnoses (past 5 years) (44.4% (18.9%-73.3%) vs 10.6% (4.6%-22.6%); p=0.029) or sexual health clinic attendance (past year) (43.8% (23.1%-66.8%) vs 5.0% (1.4%-16.5%); p=0.001). All 11 participants with AMR-conferring mutations had attended sexual health clinics (past 5 years), but none reported recent symptoms. CONCLUSIONS: This study highlights challenges in M. genitalium management and control. Macrolide resistance was present in one in six specimens from the general population in 2010-2012, but no participants with AMR M. genitalium reported symptoms. Given anticipated increases in diagnostic testing, new strategies including novel antimicrobials, AMR-guided therapy, and surveillance of AMR and treatment failure are recommended.

Sensitivity of Human Papillomavirus (HPV) Lineage and Sublineage Variant Pseudoviruses to Neutralization by Nonavalent Vaccine Antibodies.

Natural variants of human papillomavirus (HPV) are classified into lineages and sublineages based upon whole-genome sequence, but the impact of diversity on protein function is unclear. We investigated the susceptibility of 3-8 representative pseudovirus variants of HPV16, HPV18, HPV31, HPV33, HPV45, HPV52, and HPV58 to neutralization by nonavalent vaccine (Gardasil®9) sera. Many variants demonstrated significant differences in neutralization sensitivity from their consensus A/A1 variant but these were of a low magnitude. HPV52 D and HPV58 C variants exhibited >4-fold reduced sensitivities compared to their consensus A/A1 variant and should be considered distinct serotypes with respect to nonavalent vaccine-induced immunity.

Durability of the neutralizing antibody response to vaccine and non-vaccine HPV types 7 years following immunization with either Cervarix® or Gardasil® vaccine.

Bivalent (Cervarix®) and quadrivalent (Gardasil®) Human Papillomavirus (HPV) vaccines demonstrate remarkable efficacy against the targeted genotypes, HPV16 and HPV18, but also a degree of cross-protection against non-vaccine incorporated genotypes, HPV31 and HPV45. These outcomes seem to be supported by observations that the HPV vaccines induce high titer neutralizing antibodies against vaccine types and lower responses against non-vaccine types. Few data are available on the robustness of the immune response against non-vaccine types. We examined the durability of vaccine and non-vaccine antibody responses in a follow up of a head-to-head study of 12-15 year old girls initially randomized to receive three doses of Cervarix® or Gardasil® vaccine. Neutralizing antibodies against both vaccine and non-vaccine types remained detectable up to 7 years following initial vaccination and a mixed effects model was used to predict the decline in antibody titers over a 15 year period. The decline in vaccine and non-vaccine type neutralizing antibody titers over the study period was estimated to be 30% every 5-7 years, with Cervarix® antibody titers expected to remain 3-4 fold higher than Gardasil® antibody titers over the long term. The antibody decline rates in those with an initial response to non-vaccine types were similar to that of vaccine types and are predicted to remain detectable for many years. Empirical data on the breadth, magnitude, specificity and durability of the immune response elicited by the HPV vaccines contribute to improving the evidence base supporting this important public health intervention. Original trial: ClinicalTrials.gov NCT00956553.

Epidemiology of genital warts in the British population: implications for HPV vaccination programmes.

OBJECTIVES: To estimate the prevalence of, and describe risk factors for, genital warts (GWs) in the British population, following the introduction of the bivalent (human papillomavirus (HPV)-16/18) vaccination programme in girls, and prior to the switch to quadrivalent (HPV-6/11/16/18) vaccine (offering direct protection against GWs) and compare this with GW diagnoses in the prevaccination era. METHODS: Natsal-3, a probability sample survey in Britain, conducted in 2010-2012, interviewed 9902 men and women aged 16-44. Natsal-2, conducted in 1999-2001, surveyed 11 161 men and women aged 16-44. Both surveys collected data on sexual behaviour and sexually transmitted infection diagnoses using computer-assisted interview methods. RESULTS: In Natsal-3, 3.8% and 4.6% of sexually experienced men and women reported ever having a diagnosis of GWs, with 1.3% of men and 1.7% of woman reporting a GWs diagnosis in the past 5 years. GWs were strongly associated with increasing partner numbers and condomless sex. Diagnoses were more frequent in men who have sex with men (MSM) (11.6% ever, 3.3% past 5 years) and in women reporting sex with women (10.8% ever, 3.6% past 5 years). In the age group who were eligible for vaccination at the time of Natsal-3 (16-20 years), a similar proportion of same-aged women reported a history of GWs in Natsal-2 (1.9%, 1.1-3.4) and Natsal-3 (2.6%, 1.5-4.4). CONCLUSIONS: These data provide essential parameters for mathematical models that inform cost-effectiveness analyses of HPV vaccination programmes. There was no evidence of population protection against GWs conferred by the bivalent vaccine. Even with vaccination of adolescent boys, vaccination should be offered to MSM attending sexual health clinics.

Impact of naturally occurring variation in the human papillomavirus 52 capsid proteins on recognition by type-specific neutralising antibodies.

We investigated the impact of naturally occurring variation within the major (L1) and minor (L2) capsid proteins on the antigenicity of human papillomavirus (HPV) type 52 (HPV52). L1L2 pseudoviruses (PsVs) representing HPV52 lineage and sublineage variants A1, A2, B1, B2, C and D were created and tested against serum from naturally infected individuals, preclinical antisera raised against HPV52 A1 and D virus-like particles (VLPs) and neutralising monoclonal antibodies (MAbs) raised against HPV52 A1 VLP. HPV52 lineage D PsV displayed a median 3.1 (inter-quartile range 2.0-5.6) fold lower sensitivity to antibodies elicited following natural infection with, where data were available, HPV52 lineage A. HPV52 lineage variation had a greater impact on neutralisation sensitivity to pre-clinical antisera and MAbs. Chimeric HPV52 A1 and D PsV were created which identified variant residues in the FG (Q281K) and HI (K354T, S357D) loops as being primarily responsible for the reported differential sensitivities. Homology models of the HPV52 L1 pentamer were generated which permitted mapping these residues to a small cluster on the outer rim of the surface exposed pentameric L1 protein. These data contribute to our understanding of HPV L1 variant antigenicity and may have implications for seroprevalence or vaccine immunity studies based upon HPV52 antigens.

Impact of Naturally Occurring Variation in the Human Papillomavirus 58 Capsid Proteins on Recognition by Type-Specific Neutralizing Antibodies.

Background: Naturally occurring variants of human papillomavirus (HPV) 58 have been defined as lineages and sublineages but little is known about the impact of this diversity on protein function. We investigated the impact of variation within the major (L1) and minor (L2) capsid proteins of HPV58 on susceptibility to neutralizing antibodies. Methods: Pseudovirus (PsV) representing A1, A2, A3, B1, B2, C, D1, and D2 variants were evaluated for their susceptibility to antibodies elicited during natural infection, preclinical antisera generated against virus-like particles, and monoclonal antibodies (MAbs). Results: Lineage C PsV demonstrated a decreased sensitivity to antibodies raised against lineage A antigens. Exchange of the DE, FG, and/or HI loops between sublineage A1 and lineage C demonstrated that residues within all 3 loops were essential for the differential sensitivity to natural infection antibodies, with slightly different requirements for the animal antisera and MAbs. Comparison between the HPV58 A1 L1 pentamer crystal structure and an HPV58 C homology model indicated that these differences in neutralization sensitivity were likely due to subtle epitope sequence changes rather that major structural alterations. Conclusions: These data improve our understanding of the impact of natural variation on HPV58 capsid antigenicity and raise the possibility of lineage-specific serotypes.

The Impact of the National HPV Vaccination Program in England Using the Bivalent HPV Vaccine: Surveillance of Type-Specific HPV in Young Females, 2010-2016.

Background: The national human papillomavirus (HPV) immunization program was introduced in England in September 2008 using the bivalent vaccine. Methods: We collected residual vulva-vaginal swab specimens from 16 to 24-year-old women attending for chlamydia screening between 2010 and 2016 and tested for HPV DNA. We compared changes in type-specific (vaccine and nonvaccine) HPV prevalence over time and association with vaccination coverage. For women with known vaccination status, vaccine effectiveness was estimated. Results: HPV DNA testing was completed for 15459 specimens. Prevalence of HPV16/18 decreased between 2010/2011 and 2016 from 8.2% to 1.6% in 16-18 year olds and from 14.0% to 1.6% in 19-21 year olds. Declines were also seen for HPV31/33/45 (6.5% to 0.6% for 16-18 year olds and 8.6% to 2.6% for 19-21 year olds). Vaccine effectiveness for HPV16/18 was 82.0% (95% confidence interval [CI], 60.6%-91.8%) and for HPV31/33/45 was 48.7% (95% CI, 20.8%-66.8%). Prevalence of HPV16/18 was compared to findings in 2007-2008 (prevaccination) and to predictions from Public Health England's mathematical model. Discussion: Eight years after the introduction of a national HPV vaccination program, substantial declines have occurred in HPV16/18 and HPV31/33/45. The prevalence of other high-risk HPV types has not changed.

Evaluation of Dried Blood Spots and Oral Fluids as Alternatives to Serum for Human Papillomavirus Antibody Surveillance.

Human papillomavirus (HPV) vaccination elicits high-titer genotype-specific antibody responses that are associated with a reduced risk of cervical disease caused by vaccine-incorporated genotypes. Our objective was to evaluate dried blood spots (DBSs) and oral mucosal transudate (OMT) as alternative samples to serum to confirm HPV vaccine antibody status. A study was carried out to evaluate the feasibility of detecting HPV16 and HPV18 antibodies in OMT, DBSs, and sera among women who self-reported being unvaccinated or fully vaccinated with the HPV vaccine. Serum had the highest sensitivity (100%) for detection of antibodies against both HPV16 and HPV18 but the lowest specificity, due to the detection of natural infection antibodies in 16% of unvaccinated women. Conversely, DBSs and OMT had lower sensitivity (96% and 82%, respectively) but high specificity (98%). We confirmed that these antibodies were functional (i.e., neutralizing) and that their detection was quantitatively reproducible and well correlated between sample types when normalized to IgG content. DBSs and OMT are appropriate alternative sample types for HPV vaccine surveillance. These alternative sample types warrant consideration for the purposes of cervical screening, diagnosis, and management, but more work will be needed to establish the stringent parameters required for such application.IMPORTANCE Human papillomavirus (HPV) is the causative agent of cervical and other anogenital cancers. HPV vaccination, primarily targeted at young girls before the age of sexual debut, is starting to demonstrate population-level declines in HPV infection and early disease associated with vaccine-incorporated genotypes. Monitoring young women for vaccine-specific antibody is important for vaccine surveillance and may be useful as an adjunct test within a cervical screening context. We evaluated serum, dried blood spots, and oral fluid as potential samples for such applications and report robust measures of diagnostic accuracy. This is the first time a direct comparison of alternative sample types has been made between vaccinated and unvaccinated women for the detection and quantitation of HPV antibodies.

Immunogenicity of HPV prophylactic vaccines: Serology assays and their use in HPV vaccine evaluation and development.

When administered as standard three-dose schedules, the licensed HPV prophylactic vaccines have demonstrated extraordinary immunogenicity and efficacy. We summarize the immunogenicity of these licensed vaccines and the most commonly used serology assays, with a focus on key considerations for one-dose vaccine schedules. Although immune correlates of protection against infection are not entirely clear, both preclinical and clinical evidence point to neutralizing antibodies as the principal mechanism of protection. Thus, immunogenicity assessments in vaccine trials have focused on measurements of antibody responses to the vaccine. Non-inferiority of antibody responses after two doses of HPV vaccines separated by 6 months has been demonstrated and this evidence supported the recent WHO recommendations for two-dose vaccination schedules in both boys and girls 9-14 years of age. There is also some evidence suggesting that one dose of HPV vaccines may provide protection similar to the currently recommended two-dose regimens but robust data on efficacy and immunogenicity of one-dose vaccine schedules are lacking. In addition, immunogenicity has been assessed and reported using different methods, precluding direct comparison of results between different studies and vaccines. New head-to-head vaccine trials evaluating one-dose immunogenicity and efficacy have been initiated and an increase in the number of trials relying on immunobridging is anticipated. Therefore, standardized measurement and reporting of immunogenicity for the up to nine HPV types targeted by the current vaccines is now critical. Building on previous HPV serology assay standardization and harmonization efforts initiated by the WHO HPV LabNet in 2006, new secondary standards, critical reference reagents and testing guidelines will be generated as part of a new partnership to facilitate harmonization of the immunogenicity testing in new HPV vaccine trials.

Trichomonas vaginalis infection is uncommon in the British general population: implications for clinical testing and public health screening.

INTRODUCTION: Variable use of new molecular assays, asymptomatic infections and a lack of population data mean that the population burden of Trichomonas vaginalis is uncertain. We investigated the age-specific prevalence of T. vaginalis within the sexually active British general population to inform testing strategies. METHODS: Britain's third National Survey of Sexual Attitudes and Lifestyle (Natsal-3) is a probability sample survey of 15 162 individuals aged 16-74 years, undertaken during 2010-2012. Urine from 4386 participants aged 16-44 years reporting ≥1 lifetime sexual partner was tested for T. vaginalis using in-house real-time PCR. RESULTS: Urinary T. vaginalis was detected in seven women and no men providing urine samples, giving a weighted prevalence estimate of 0.3% (95% CI 0.1% to 0.5%) in sexually experienced women aged 16-44 years. Of the seven women with T. vaginalis detected, four were of black or mixed ethnicity (prevalence 2.7% (0.9% to 7.7%) in this group) and five reported recent partners of black or mixed ethnicity. Six of the women reported symptoms, and five reported sexual health clinic attendance in the past 5 years (prevalence in those reporting clinic attendance: 1.0% (0.4% to 2.3%)). The prevalence of a self-reported history of T. vaginalis (past 5 years) was 0.1% (0.0% to 0.2%) in women and 0.0% (0.0% to 0.2%) in men aged 16-44 years. CONCLUSIONS: Our British population prevalence estimates indicate that T. vaginalis is a rare infection. These data support policies that restrict asymptomatic screening for T. vaginalis and suggest deployment of molecular tests should be focused within clinical settings and guided by symptoms and local demography.