Prevalence of genital HPV infections and HPV serology in adolescent girls, prior to vaccination

Comparative Analysis of HPV16 Variants in the Untranslated Regulatory Region, L1, and E6 Genes among Vaccinated and Unvaccinated Young Women: Assessing Vaccine Efficacy and Viral Diversity

HPV16 is occasionally detected in vaccinated women who received the bivalent HPV16/18 vaccine, usually at low viral loads. This study explored potential differences in HPV16 variants between vaccinated and unvaccinated women. HPV16-postive viral loads were detected in 1.9% (17/875) and 13% (162/760) of vaccinated and unvaccinated women, respectively, showcasing the vaccine's high efficacy. The L1, E6, and URR regions of HPV16 were sequenced from genital swabs from 16 vaccinated and 25 unvaccinated women in the HAVANA (HPV Among Vaccinated And Non-vaccinated Adolescents) study. The majority of HPV16 variants from vaccinated and unvaccinated women clustered similarly with sub-lineages A1 and A2. Additionally, a separate cluster within lineage A was found, with the variants sharing the L1-located SNP A753G (synonymous) and the URR-located SNP T340C, which did not occur in the other variants. Furthermore, four variants from vaccinated women had relatively long branches, but were not characterized by specific SNPs. The frequency of G712A in the URR was the only SNP observed to be marginally higher among vaccinated women than unvaccinated women. Non-synonymous SNPs T266A in the FG-loop of L1 and L83V in E6 were common among variants from vaccinated and unvaccinated women, but present in similar frequencies. In conclusion, the detection of HPV16 in vaccinated (and unvaccinated) women seemed to be the result of random circulation within this study population.

Effects of 2 and 3 Vaccinations With the Bivalent Human Papillomavirus (HPV) Vaccine on the Prevalence and Load of HPV in Clearing and Persistent Infections in Young Women

BACKGROUND

Human papillomavirus (HPV) viral load (VL) is associated with persistence, which increases cervical cancer risk. The bivalent vaccine protects against oncogenic HPV-16/18 and cross-protects against several nonvaccine types. We examined the effect of 2-dose (2D) and 3-dose (3D) vaccination on HPV prevalence and VL in clearing infections and persistent infections, 6 years and 12 years postvaccination, respectively.

METHODS

Vaginal swabs collected from the "HPV Amongst Vaccinated and Non-vaccinated Adolescents" study (HAVANA, 3D-eligible) and HAVANA-2 (2D-eligble) participants were genotyped for HPV with the SPF10-DEIA-LiPA25 system. HPV VL was measured with type-specific quantitative polymerase chain reaction (qPCR).

RESULTS

HPV-16, -18, -31, -33, and -45 clearing and/or persistent infection prevalence and HPV-16, -18, and -31 VLs in clearing infections were significantly reduced in 3D-vaccinated women compared to unvaccinated women. Except for HPV-11 and -59 clearing infections, no significant VL differences were observed among vaccinated women, ≤6 and >6 years post-vaccination. Infection numbers were low in 2D-eligible women, with no HPV-16/18 in vaccinated women. No VL differences for the remaining types were found.

CONCLUSIONS

3D vaccination reduces HPV prevalence in clearing infections and persistent infections and decreases HPV VLs in clearing infections, 12 years post-vaccination for vaccine and several nonvaccine types. 2D-eligible women had low infection numbers, with no HPV-16/18 among vaccinated women.

High vaccine effectiveness persists for ten years after HPV16/18 vaccination among young Dutch women

The current study describes the long-term effectiveness of three-dose HPV16/18 vaccination among Dutch women who were eligible for vaccination during a catch-up campaign and were followed in an observational cohort study. Ten years post vaccination, vaccine effectiveness (VE) was estimated using generalized estimating equation models. VE against persistent infections with vaccine type infections (HPV16/18) was high at 95.8%. For cross protective type persistent infections (HPV31/33/45) this was 64.6%. There were no indications of waning of protection over time. This indicates solid long-term protection is provided by the vaccine and is promising with regard to the future clinical impact.

Measuring vaccine effectiveness against persistent HPV infections: a comparison of different statistical approaches

BACKGROUND

Persistent high-risk human papillomavirus (HPV) infection is endorsed by the World Health Organization as an intermediate endpoint for evaluating HPV vaccine effectiveness/efficacy. There are different approaches to estimate the vaccine effectiveness/efficacy against persistent HPV infections.

METHODS

We performed a systematic literature search in Pubmed to identify statistical approaches that have been used to estimate the vaccine effectiveness/efficacy against persistent HPV infections. We applied these methods to data of a longitudinal observational study to assess their performance and compare the obtained vaccine effectiveness (VE) estimates.

RESULTS

Our literature search identified four approaches: the conditional exact test for comparing two independent Poisson rates using a binomial distribution, Generalized Estimating Equations for Poisson regression, Prentice Williams and Peterson total time (PWP-TT) and Cox proportional hazards regression. These approaches differ regarding underlying assumptions and provide different effect measures. However, they provided similar effectiveness estimates against HPV16/18 and HPV31/33/45 persistent infections in a cohort of young women eligible for routine HPV vaccination (range VE 93.7-95.1% and 60.4-67.7%, respectively) and seemed robust to violations of underlying assumptions.

CONCLUSIONS

As the rate of subsequent infections increased in our observational cohort, we recommend PWP-TT as the optimal approach to estimate the vaccine effectiveness against persistent HPV infections in young women. Confirmation of our findings should be undertaken by applying these methods after longer follow-up in our study, as well as in different populations.

Persisting Antibody Response 9 Years After Bivalent Human Papillomavirus (HPV) Vaccination in a Cohort of Dutch Women: Immune Response and the Relation to Genital HPV Infections

The bivalent human papillomavirus (HPV) vaccine is highly effective and induces robust serological responses. Using a Dutch prospective cohort initiated in 2009, including 744 vaccinated and 294 unvaccinated girls (1993–1994) who provide a vaginal self-swab sample, serum sample, and questionnaire yearly, we report a high, persisting antibody response up to 9 years after vaccination for vaccine types HPV-16 or HPV-18. Antibodies against nonvaccine HPV types 31, 33, 45, 52, and 58 were lower but still significantly higher than in unvaccinated individuals. This was also reflected in the seroprevalence. We compared participant characteristics and antibody levels between vaccinated women with and those without HPV infections 1 year before infection (204 incident and 64 persistent infections), but we observed no consistent difference in type-specific antibody levels. Having a high-risk HPV infection was associated with sexual risk behavior and smoking 1 year before infection. Although high antibody levels are necessary for protection, our study suggests that on the individual level other factors such as HPV exposure or antibody avidity could be important.

Effect of the bivalent HPV vaccine on viral load of vaccine and non-vaccine HPV types in incident clearing and persistent infections in young Dutch females

Background

HPV vaccination with the bivalent vaccine is efficacious against HPV16 and 18 infections and cross-protection against non-vaccine HPV types has been demonstrated. Here, we assessed (cross-) protective effects of the bivalent HPV16/18 vaccine on incident and persistent infections and viral load (VL) of fifteen HPV types in an observational cohort study monitoring HPV vaccine effects.

Methods

Vaginal samples were obtained annually. Type-specific VL assays were developed for HPV6,11,31 33,35,39,45,51,52,56,58,59 and 66 and used in addition to existing HPV16 and 18 assays. Rate differences of incident clearing and persistent infections were correlated with differences in VL and vaccination status.

Results

HPV16/18 vaccination resulted in significantly lower incidence of HPV16/18 infections and significantly lower VL in breakthrough HPV16 (p<0.01) and 18 infections (p<0.01). The effects of vaccination on non-vaccine type VL were ambiguous. Incidence and/or persistence rates of HPV31, 33, 35 and 45 were reduced in the vaccinated group. However, no significant type specific VL effects were found against HPV31, 33, 45, 52 in the vaccinated group. For HPV 6, 59 and 66 no significant reductions in numbers of incident and persistent infections were found, however borderline) VL reductions following vaccination were observed for HPV6 (p = 0.01), 59 (p = 0.10) and 66 (p = 0.03), suggesting a minor effect of the vaccine on the VL level of these HPV types. Overall, vaccination resulted in infections with slightly lower VL, irrespective of HPV type.

Conclusions

In conclusion, vaccination with the bivalent HPV16/18 vaccine results in significantly reduced numbers of HPV16 and 18 incidence rates and reduced VL in breakthrough infections. Significant reductions in incident and/or persistent HPV31, 33, 35 and 45 infections were found, but no significant effect was observed on the VL for infections with these types. For the other non-vaccine HPV types no reduction in incident and/or persistent infections were found, but overall the VL tended to be somewhat lower in vaccinated women.

Ten years of HPV vaccination in the Netherlands: current evidence and future challenges in HPV-related disease prevention

INTRODUCTION

Girls-only vaccination against human papillomavirus (HPV) type 16 and 18 was implemented in the Netherlands in 2009. Despite the evidence of the efficacy against precancerous lesions, cross-protection induced by the vaccine and a greater potential for cancer prevention than cervical cancer only, vaccine coverage in the girls-only program has remained below target levels.

AREAS COVERED

In this paper, we review the literature from the Netherlands on the effectiveness and cost-effectiveness of HPV vaccination since vaccine introduction, give an account of the coverage, safety and effectiveness of HPV vaccination as has been reported in the Dutch surveillance program and discuss challenges of the current HPV vaccination program.

EXPERT COMMENTARY

Girls-only HPV vaccination may confer a substantial health gain in HPV-related disease prevention. However, vaccine coverage declined remarkably recently possibly related to safety concerns, limiting the benefits from girls' vaccination and increasing the potential additional benefit of sex-neutral HPV vaccination. Considering the emergence of novel vaccination and screening options and the change from cytology- to HPV-based screening in 2017, further research is required to inform decisions on the optimization of an integrated vaccination and screening program.

Study protocol of the iMPaCT project: a longitudinal cohort study assessing psychological determinants, sexual behaviour and chlamydia (re)infections in heterosexual STI clinic visitors

Background

Chlamydia trachomatis (chlamydia), the most commonly reported sexually transmitted infection (STI) in the Netherlands, can lead to severe reproductive complications. Reasons for the sustained chlamydia prevalence in young individuals, even in countries with chlamydia screening programs, might be the asymptomatic nature of chlamydia infections, and high reinfection rates after treatment. When individuals are unaware of their infection, preventive behaviour or health-care seeking behaviour mostly depends on psychological determinants, such as risk perception. Furthermore, behaviour change after a diagnosis might be vital to reduce reinfection rates. This makes the incorporation of psychological determinants and behaviour change in mathematical models estimating the impact of interventions on chlamydia transmission especially important. Therefore, quantitative real-life data to inform these models is needed.

Methods

A longitudinal cohort study will be conducted to explore the link between psychological and behavioural determinants and chlamydia (re)infection among heterosexual STI clinic visitors aged 18–24 years. Participants will be recruited at the STI clinics of the public health services of Amsterdam, Hollands Noorden, Kennemerland, and Twente. Participants are enrolled for a year, and questionnaires are administrated at four time points: baseline (before an STI consultation), three-week, six-month and at one-year follow-up. To be able to link psychological and behavioural determinants to (re)infections, participants will be tested for chlamydia at enrolment and at six-month follow-up. Data from the longitudinal cohort study will be used to develop mathematical models for curable STI incorporating these determinants to be able to better estimate the impact of interventions.

Discussion

This study will provide insights into the link between psychological and behavioural determinants, including short-term and long-term changes after diagnosis, and chlamydia (re)infections. Our mathematical model, informed by data from the longitudinal cohort study, will be able to estimate the impact of interventions on chlamydia prevalence, and identify and prioritise successful interventions for the future. These interventions could be implemented at STI clinics tailored to psychological and behavioural characteristics of individuals.

Trial registration

Dutch Trial Register NTR-6307. Retrospectively registered 11-nov-2016.

High-risk human papillomavirus seroprevalence in men and women of six different ethnicities in Amsterdam, the Netherlands: The HELIUS study

Background

Ethnic variations in the (sero)prevalence of Human Papillomavirus (HPV) and HPV related diseases have been observed previously. We explored if high-risk HPV (hrHPV) seropositivity indeed differs among 6 ethnic groups in Amsterdam the Netherlands and assessed if hrHPV seroprevalence is higher among women than men within each ethnic group, both after adjustment for confounders.

Methods

From the multi-ethnic HEalthy Life In an Urban Setting (HELIUS) study in Amsterdam (the Netherlands) we randomly selected 4637 men and women aged 18–44 years with a Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Moroccan, or Turkish ethnicity. Blood samples were tested for HPV-16,−18,−31,−33,−45,−52, and −58 antibodies using a validated Luminex-based multiplex serology assay. We assessed the association of both ethnicity and gender with hrHPV seropositivity using logistic regression models with generalised estimating equations.

Results

The hrHPV seroprevalence in Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Moroccan, and Turkish participants was 18%, 12%, 23%, 19%, 17%, and 15% in men, and 30%, 22%, 34%, 31%, 14%, and 15% in women, respectively. HrHPV seroprevalence of non-Dutch men did not differ significantly from Dutch men. HrHPV seroprevalence was significantly higher among African Surinamese women, and significantly lower among Moroccan and Turkish women when compared to Dutch women. These differences were not significant anymore after adjustment for demographic, health, and sexual behavioural differences between ethnicities. HrHPV seroprevalence varied by age, age of sexual debut, and lifetime sexual partners among women but not among men. Seroprevalence of hrHPV was higher among women than among men, except in the Turkish group.

Conclusion

Among women hrHPV seroprevalence differed by ethnicity, yet among men no pronounced differences were observed across ethnicities.

•

Women have a higher hrHPV seroprevalence than men, except in the Turkish group.

•

Seroprevalence of hrHPV varies by ethnicity among women in Amsterdam.

•

Among men no pronounced differences in hrHPV seroprevalence by ethnicity are observed.

•

Differences by ethnicity in women are attributable to differences in sexual behaviour.

•

HPV serology is not a useful indicator of sexual exposure among heterosexual men.

Genital HPV in Children and Adolescents: Does Sexual Activity Make a Difference?

STUDY OBJECTIVE

To compare the prevalence of human papillomavirus (HPV) genital infection among prepubertal children, sexually active and not sexually active adolescents, and assess potential risk factors for transmission.

DESIGN

Prospective study.

SETTING

Outpatient adolescent health clinic.

PARTICIPANTS

Ninety-five girls aged 2-21 years; 38 sexually active adolescents (group A), 28 not sexually active adolescents (group B), and 29 prepubertal children (group C).

INTERVENTIONS

Participants' vaginal or cervical specimens were tested for HPV with the CLART HPV 2 assay (Clinical Array Technology, Genomica, Madrid, Spain) and for cytological abnormalities with liquid-based cytology.

MAIN OUTCOME MEASURES

Differences in prevalence of low- and high-risk HPV infections among the 3 groups.

RESULTS

Genital HPV was detected in 37.9% (36/95) of all participants; 47.4% (18/38) of group A, 28.6% (8/28) of group B, and 34.5% (10/29)of group C (P = .27). Multiple HPV infection was detected in 26.3% (10/38), 10.7% (3/28), and 13.8% (4/29) of groups A, B, and C, respectively (P = .21). High-risk genotypes were detected in 47.4% (18/38), 28.6% (8/28), and 24.1% (7/29) of groups A, B, and C, respectively (P = .10). Main high-risk genotypes were HPV 16 (27%, 10/37), HPV 31 (21.6%, 8/37 ), HPV 35 (13.5%, 5/37), HPV 53 (13.5%, 5/37), and low-risk HPV 6 (18.9%, 7/37). Sexual activity was associated with increased risk for genital high-risk HPV infection (odds ratio = 3.41; 95% confidence interval, 1.19-9.78); specifically with HPV 33 and HPV 51. Forty percent of sexually active adolescents with normal cervical cytology were infected with high-risk HPV types. Family history of skin HPV was positively associated with genital HPV in the sexually active group (odds ratio = 2.01; 95% confidence interval, 1.17-3.46).

CONCLUSION

Timeline and target population for HPV vaccination might need to be reappraised, in view of significant nonsexual transmission of genital HPV so early in childhood.

Human papillomavirus prevalence and type distribution in urine samples from Norwegian women aged 17 and 21 years: A nationwide cross-sectional study of three non-vaccinated birth cohorts

Background

The aim of the current study was to assess the HPV prevalence in unscreened and unvaccinated young women living in Norway, to provide important baseline data for early estimation of the impact of the HPV vaccination program.

Methods

A total of 13,129 self-sampled urine samples from two complete birth-cohorts of 17-year old women born in 1994 and 1996 and one third of a birth-cohort of 21-year old women born in 1990, were analysed for the presence of 37 HPV types using PCR and a DNA hybridization technique.

Results

In the two birth cohorts of 17-year old women, HPV was detected in 19.9% (95% CI 18.8–20.9) and 15.4% (95% CI 14.5–16.3), respectively. High-risk HPV types were detected in 11.2% (95% CI 10.3–12.0) and 7.6% (95% CI 6.9–8.2), respectively, while vaccine types were detected in 7.4% (95% CI 6.7–8.1) and 6.0% (95% CI 5.4–6.6), respectively. Among the 21-year old women HPV was detected in 45.4% (95% CI 42.9–47.8), whereas high-risk types were detected in 29.8% (95% CI 27.5–32.0). Vaccine types (HPV 6, 11, 16, 18) were detected in 16.2% (95% CI 14.4–18.1).

Conclusion

This large population based study confirms that HPV testing in urine samples is easy and highly feasible for epidemiological studies and vaccine surveillance in young women. HPV was very common and a broad spectrum of HPV types was identified. Differences in HPV prevalence was seen both between age groups and between the two birth cohorts of 17-year old women.

•

Self-sampled urine proved suitable for large scale HPV testing.

•

HPV 16 and 18 was very common among young girls.

•

A wide variety of HPV types circulates in the population.

•

HPV was detected in nearly half of the 21-year old women.

•

HPV was detected in 15–20% of the 17-year old women.

Higher prevalence of human papillomavirus infection in adolescent and young adult girls belonging to different Indian tribes with varied socio-sexual lifestyle

BACKGROUND

Despite high prevalence of human papillomavirus (HPV) infection and cervical cancer in Indian women, no study has been done in tribal populations whose socio-sexual lifestyle is different. Therefore, HPV screening has been carried out in pre-adolescent, adolescent and young adult tribal girls using self-collected urine samples.

METHODS

20-35 ml self-collected midstream urine samples were obtained from a total of 2278 healthy tribal girls (9-25 years) comprising pre-adolescent, adolescent and young adults from three Indian states: Madhya Pradesh, Jharkhand and Chhattisgarh. β-globin positive 2034 samples were employed for HPV detection and genotyping.

RESULTS

The overall prevalence of HPV infection in tribal girls was 12.9% (262/2034). More than 65% (172/262) of them were infected with HR-HPV types of which HPV16 was the most predominant type (54%). Young adult girls aged 18-25 years showed a significantly higher prevalence of HPV infection (19.2%; OR = 3.36; 95% CI 2.97-6.34, P<0.001) as compared to that in adolescent (11.4%; OR = 1.82; 95% CI 1.20-2.76, P<0.01) or pre-adolescent girls (6.6%).

CONCLUSION

This is a first study showing significantly a very high prevalence of HPV infection in adolescent and young adult tribal girls possibly due to different socio-sexual behavior, indicating a serious health concern for Indian tribal women.

Effectiveness of human papillomavirus vaccine against incident and persistent infections among young girls: Results from a longitudinal Dutch cohort study

INTRODUCTION

Because of the long interval between infection with high-risk human papillomavirus (hrHPV) and development of cervical cancer surrogate markers for cancer incidence are necessary to monitor vaccine effectiveness (VE). The aim of this study was to calculate VE of HPV16/18 vaccination by annually assessing incident and persistent infections among (un)vaccinated girls from the general Dutch population up to 3 years after vaccination.

METHODS

In 2009, 1668 girls (54% vaccinated) aged 14-16 years were enrolled in a prospective cohort study. Annually, questionnaire data were obtained, and a vaginal swab was tested for type-specific HPV DNA with SPF10-LiPA. VE was estimated by a Poisson model comparing type-specific infection rates in (un)vaccinated girls.

RESULTS

The adjusted VE (95% CI) was 73% (49-86%) against incident infections with HPV16/18 and 72% (52-84%) against HPV16/18/31/45. VE against persistent HPV16/18 was 100% and 76% (-17 to 95%) against HPV16/18/31/45. This number was lower (36%) when girls who were positive for HPV16 and 18 at baseline were included in the analysis. The overall VE for hrHPV types combined was small. Although 96% of girls were HPV-naïve at baseline, the cumulative 36-month incidence for any HPV was 20%, indicating high sexual activity.

DISCUSSION

Vaccination is effective against incident and persistent infections with HPV16/18 and HPV16/18/31/45. Low VE against persistent HPV16/18 infection in girls positive at baseline indicates importance of vaccination before sexual debut.

The original SPF10 LiPA25 algorithm is more sensitive and suitable for epidemiologic HPV research than the SPF10 INNO-LiPA Extra

Two commercial HPV tests target the same 65 bp fragment of the human papillomavirus genome (designated SPF10): the original HPV SPF10 PCR-DEIA-LiPA25 system, version 1, (LiPA25) and the INNO-LiPA HPV Genotyping Extra (INNO-LiPA). The original SPF10 LiPA25 system was designed to have high analytical sensitivity and applied in HPV vaccine and epidemiology studies worldwide. But due to apparent similarities, this test can be easily confused with INNO-LiPA, a more recent assay of which the intended use, i.e., epidemiological or clinical, is currently unclear. The aim was to compare the analytical sensitivity of SPF10 LiPA25 to that of INNO-LiPA on the level of general HPV detection and genotyping. HPV testing by both assays was performed on the same DNA isolated from cervical swab (n = 365) and biopsy (n = 42) specimens. In cervical swabs, SPF10 LiPA25 and INNO-LiPA identified 35.3% and 29.3% multiple infections, 52.6% and 51.5% single infections, and no HPV type in 12.1% and 19.2%, respectively. Genotyping results were 64.7% identical, 26.0% compatible and 9.3% discordant between both methods. SPF10 LiPA25 detected significantly more genotypes (p < 0.001). The higher analytical sensitivity of SPF10 LiPA25 was confirmed by the MPTS123 genotyping assay. HPV positivity by the general probes in SPF10 DEIA was significantly higher (87.9%) than by those on INNO-LiPA (77.0%) (kappa = 0.592, p < 0.001). In cervical biopsies, SPF10 LiPA25 and INNO-LiPA identified 21.4% and 9.5% multiple types, 76.2% and 81.0% single types, and no type in 2.4% and 9.5%, respectively. Between both tests, the identification of genotypes was 76.3% identical, 14.3% compatible and 9.5% discordant. Overall, significantly more genotypes were detected by SPF10 LiPA25 (kappa = 0.853, p = 0.022). HPV positivity was higher by the SPF10 DEIA (97.6%) than by the INNO-LiPA strip (92.9%). These results demonstrate that SPF10 LiPA25 is more suitable for HPV genotyping in epidemiologic and vaccine-related studies, due to its higher analytical sensitivity.

TEMPORARY REMOVAL: The original SPF10 LiPA25 algorithm is more sensitive and suitable for epidemiologic HPV research than the SPF10 INNO-LiPA Extra

The publisher regrets that this article has been temporarily removed. A replacement will appear as soon as possible in which the reason for the removal of the article will be specified, or the article will be reinstated. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Population- and type-specific clustering of multiple HPV types across diverse risk populations in the Netherlands

In view of possible type replacement upon introduction of human papillomavirus (HPV) vaccination, we aimed to explore patterns of type-specific clustering across populations with various background infection risks. A total of 3,874 women from 3 cross-sectional studies in the Netherlands (in 2007-2009) provided vaginal self-samples, which were tested for 25 HPV genotypes by a sensitive molecular assay (SPF10 line probe assay, DDL Diagnostic Laboratory, Voorburg, the Netherlands). The number of concurrent HPV infections per woman was studied by Poisson regression. Associations between HPV types were investigated by generalized estimating equation analyses. The prevalence of any HPV type was 14% in a population-based study, 54% in a chlamydia screening intervention study, and 73% in a study among attendees of sexually transmitted infection clinics. Overall, multiple HPV infections were detected in 26% of the women. The number of concurrent HPV infections conformed to an overdispersed Poisson distribution, even after correction for known risk factors. Types differed significantly in their tendencies to be involved in coinfections, but no evidence for particular type-type interactions was found. Moreover, the strongest associations were observed in the lowest-risk population and vice versa.We found no indications of pairwise interactions, but our findings do suggest that clustering differs among HPV types and varies across risk groups.

Detection and genotyping of human papillomavirus in urine samples from unvaccinated male and female adolescents in Italy

The introduction of vaccination against Human Papillomavirus (HPV) in adolescent girls in 2006 has focused virological surveillance on this age group. As few studies have evaluated HPV infections in young populations, further data are needed in order to improve and extend prophylactic policy and to monitor epidemiological changes. The present study aimed at evaluating overall and type-specific HPV prevalence in both female and male adolescents in Italy. HPV DNA detection and genotyping was performed on urine samples collected from 870 unvaccinated adolescents (369 females, 501 males, 11-18 years of age) in five cities in Italy. Following DNA extraction by means of a commercial kit (NucliSENS(®)-miniMAG(®), bioMérieux), the L1 gene fragment was PCR amplified and genotyped by restriction fragment length polymorphism analysis. HPV DNA was detected in 1.5% of all samples, and in 3% and 0.4% of samples from females and males, respectively. In approximately 70% of HPV DNA positive adolescents, the infection was due to a single genotype, with 88.9% of genotypes belonging to the HR-clade. The only two HPV-positive boys (14 and 18 years old) had HPV-70 genotype. Only one of the 11 HPV-infected girls was in the 11-14 age-group. HPV prevalence was 4.2% in girls aged 15-18 years and 60% of infections were due to vaccine types HPV-16 or HPV-6/-11. This is one of the few studies, the first conducted in Italy, on HPV infection in adolescents. Urine testing is the easier way of detecting HPV infection in younger populations. Our data revealed a very low HPV prevalence, and no infections were observed in the 12-year-old vaccine target population. The majority of infections were seen in females aged 15-18 years. Overall, more than 50% and 30% of the potentially persistent HPV infections detected in this group could have been prevented by the quadrivalent and the bivalent vaccines, respectively.

Characteristics of HPV-specific antibody responses induced by infection and vaccination: cross-reactivity, neutralizing activity, avidity and IgG subclasses

OBJECTIVES

In order to assess HPV-specific IgG characteristics, we evaluated multiple aspects of the humoral antibody response that will provide insight in the HPV humoral immune response induced by HPV infection and vaccination.

METHODS

Cross-reactivity of HPV-specific antibodies induced by infection or vaccination was assessed with VLP16 or 18 inhibition using a VLP-based multiplex immunoassay (MIA) for HPV16, 18, 31, 33, 45, 52 and 58. HPV16/18 specific IgG1-4 subclasses and avidity were determined with the VLP-MIA in sera after HPV infection and after vaccination. Neutralizing antibodies were determined in a small subset of single-seropositive and multi-seropositive naturally derived antibodies.

RESULTS

Naturally derived antibodies from single-positive sera were highly genotype-specific as homologue VLP-inhibition percentages varied between 78-94%. In multi-positive sera, cross-reactive antibodies were observed both within and between α7 and α9 species. After vaccination, cross-reactive antibodies were mainly species-specific. Avidity of vaccine-derived HPV-specific antibodies was 3 times higher than that of antibodies induced by HPV infection (p<0.0001). IgG1 and IgG3 were found to be the predominant subclasses observed after HPV infection and vaccination. In the small subset tested, the number of single-positive sera with neutralizing capacity was higher than of multi-positive sera.

CONCLUSION

Naturally derived HPV-specific antibodies from single-positive samples showed different characteristics in terms of cross-reactivity and neutralizing capacity compared with antibodies from multi-positive sera. Post-vaccination, HPV antibody avidity was approximately 3 times higher than antibody avidity induced by HPV infection. Therefore, antibody avidity might be a potential surrogate of protection.

Comparison of different assays to assess human papillomavirus (HPV) type 16- and 18-specific antibodies after HPV infection and vaccination

We compared the measurement of human papillomavirus (HPV)-specific serum antibody levels with the virus-like-particle multiplex immunoassay (VLP-MIA), competitive Luminex immunoassay (cLIA), and glutathione S-transferase (GST) L1-based MIA. Using a large panel of serum samples, these assays showed mutually good correlations for both naturally induced and vaccine-derived HPV-specific antibody levels. However, an adaptation of the GST L1-based MIA resulted in an improved correlation with both cLIA and VLP-MIA.

High HPV-51 prevalence in invasive cervical cancers: results of a pre-immunization survey in North Sardinia, Italy

Background

Human Papilloma virus (HPV) is recognized as the etiological agent of benign and malignant ano-genital lesions. The most prevalent genotypes associated with cervical carcinoma are HPV-16 and -18 worldwide. However, recent studies have emphasized the role of other genotypes, such as HPV-51, in the pathogenesis of cervical dysplasia. The aim of the study was to estimate the burden of HPV-51 infection in invasive cervical malignant lesions in Northern Sardinia, Italy.

Methods/Principal Findings

An observational, retrospective, prevalence, mono-center study was carried out to evaluate the presence of HPV genotypes in tissues biopsies of cervical lesions (CIN-1, CIN-2, CIN-3 and invasive carcinoma) gathered from 1996 to 2009. Biological samples were collected from women admitted consecutively to a tertiary university hospital situated in Sassari, Italy. Molecular methods were used to identify 28 oncogenic HPV types. A total of 155 formalin-fixed and paraffin-embedded cervical tissue samples were analyzed. Approximately half of the cervical lesions were classified as invasive carcinoma. HPV-DNA was detected in 71% of the samples, with a higher frequency (100%) in those categorized as invasive neoplasia. Mono- or co-infections were demonstrated in 45.8% and 25.8% of the cervical samples, respectively. Overall, the most prevalent HPV types were -16 (49%) and -51 (19.4%), with an increased frequency of detection associated with the severity of the cervical lesions.

Conclusions/Significance

This survey highlights for the first time the relevant role of HPV-51 infection in the pathogenesis of invasive cervical cancer prior to the introduction of a vaccination program. Although a selection bias could have influenced the results, other recent studies have described the impact of HPV-51. This remarkable epidemiological element should be carefully evaluated, particularly in the view of opting for preventive vaccines, whose cross-protection patterns determine their efficacy in protecting against infection from HPV types that are not included in the vaccine itself.

A Viable and Simple Self-Sampling Method for Human Papillomavirus Detection among South African Adolescents

BACKGROUND

Self-sampling for Human Papillomavirus (HPV) testing may offer improved patient acceptability, decreased cost, and greater practicality than clinician collection of specimens. HPV testing among adolescents is necessary to conduct vaccine surveillance and may play a role in cervical cancer screening among some populations.

METHODS

A cross-sectional prevalence study was conducted to compare the results of self-collected and clinician-collected specimens for Human papillomavirus (HPV) testing among South African adolescent females. All participants provided self-sampled vaginal swabs and underwent clinician-collection of cervical swabs for HPV DNA analysis. The level of agreement between HPV DNA results from the two specimen collection methods was measured.

RESULTS

The level of agreement between HPV DNA results from self-collected and clinician-collected specimens was high (κ=86.7; p<0.001). A high prevalence of HPV overall was found by both specimen collection methods (57%; 95% CI 0.37-0.75). Low-risk HPV (LR-HPV) types were found slightly more frequently in self-collected specimens.

CONCLUSION

There is a high level of agreement between the HPV DNA results from self-collected and clinician-collected specimens. Self-collection of specimens for HPV testing is a viable alternative among adolescents.

Detection of systemic and mucosal HPV-specific IgG and IgA antibodies in adolescent girls one and two years after HPV vaccination

The bivalent HPV16/18 vaccine induces high antibody concentrations in serum while data about antibody responses in the cervix are limited. In this study, we investigated pre- and post-vaccination antibody responses against seven high-risk HPV types by detection of IgG and IgA HPV-specific antibodies in cervical secretion samples (CVS) and serum. From an HPV vaccine monitoring study CVS and serum samples were available (pre-vaccination (n = 297), one year (n = 211) and two years (n = 141) post-dose-one vaccination) from girls aged 14-16 y. The girls were vaccinated with the bivalent HPV vaccine at months 0, 1 and 6. CVS was self-sampled using a tampon. Samples were tested for HPV-specific antibodies (HPV16/18/31/33/45/52/58) by a VLP-based multiplex immunoassay. Post-vaccination, IgG and IgA antibody levels for HPV16/18 were detectable in CVS and amounted to 2% and 1% of the IgG and IgA antibody levels observed in serum, respectively. The antibody levels remained constant between one and two years after vaccination. The correlation between CVS and serum was similar for IgG and IgA vaccine-derived antibody levels for HPV16 (rs = 0.58, rs = 0.54) and HPV18 (rs = 0.50, rs = 0.55). Vaccine-derived IgG antibody levels against cross-reactive HPV types in CVS and in serum were highest for HPV45. No IgA cross-reactive antibody responses could be detected in CVS. Post-vaccination, HPV16/18 IgG and IgA antibodies are not only detectable in serum but also in CVS. The correlation of HPV16/18 IgG antibody levels between serum and CVS suggests that vaccine induced HPV antibodies transudate and/or exudate from the systemic circulation to the cervical mucosa to provide protection against HPV infections.