Human papillomavirus infection: an anonymous prevalence study in South Wales, UK

High Prevalence of HPV 51 in an Unvaccinated Population and Implications for HPV Vaccines

Human papillomavirus (HPV) is detected in 99.7% of cervical cancers. Current vaccines target types 16 and 18. Prior to vaccination implementation, a prospective cohort study was conducted to determine baseline HPV prevalence in unvaccinated women in Wales; after HPV16 and HPV18, HPV 51 was found to be most prevalent. This study aimed to re-assess the unexpected high prevalence of HPV 51 and consider its potential for type-replacement. Two hundred HPV 51 positive samples underwent re-analysis by repeating the original methodology using HPV 51 GP5+/6+ PCR-enzyme immunoassay, and additionally a novel assay of HPV 51 E7 PCR. Data were correlated with age, social deprivation and cytology. Direct repeat of HPV 51 PCR-EIA identified 146/195 (75.0%) samples as HPV 51 positive; E7 PCR identified 166/195 (85.1%) samples as HPV 51 positive. HPV 51 prevalence increased with cytological grade. The prevalence of HPV 51 in the pre-vaccinated population was truly high. E7 DNA assays may offer increased specificity for HPV genotyping. Cross-protection of current vaccines against less-prevalent HPV types warrants further study. This study highlights the need for longitudinal investigation into the prevalence of non-vaccine HPV types, especially those phylogenetically different to vaccine types for potential type-replacement. Ongoing surveillance will inform future vaccines.

Prevalence and Distribution of Vaccine-Preventable Genital Human Papillomavirus(HPV) Genotypes in Ghanaian Women Presenting for Screening

BACKGROUND

Cervical cancer is the most common gynaecologic cancer in Ghana where it is also the second most common cause of all female cancers. A number of vaccines are available to provide both individual and population-level protection against persistent infection with high-risk human papillomaviruses (HR-HPV) and reduce the burden of cervical cancer. Data on the epidemiology of vaccine-preventable papillomaviruses in Ghana is scant.

METHODS

A cross-sectional observational study was implemented from May 2011 to November 2014 to understand the epidemiology of genital human papillomavirus (HPV) genotypes and cervical dysplasia in the Greater Kumasi area of Ghana. A nested multiplex polymerase chain reaction (NMPCR) assay incorporating degenerate E6/E7 consensus primers and type-specific primers was used for the detection and typing of eighteen (18) HPV genotypes among women who had never attended cervical screening prior to this study.

RESULTS

The general prevalence of HPV infection in Kumasi was 37.2%. The age-standardized prevalence was 40.9% overall. The frequency of HR-HPV genotypes present in decreasing order were HPV-52, -56, -35, -18, -58, -68, -51, -39, -45, -16, -59, -33 and -31. Low-risk HPVs were also detected in the following order: HPV-42, -43, -66, -6/11 and -44.

CONCLUSIONS

The study shows that currently available prophylactic vaccines have the potential to be useful in the primary prevention of HPV infections in the country. This study strengthens the belief that prophylactic HPV vaccination could be a long-term strategy to reduce the burden of HPV infections and potentially reduce the burden of HPV-associated cancers and epithelial cell abnormalities among health-seeking women in Kumasi. Efforts to make vaccines available to young girls should be prioritized.

Prevalence of HPV infection among sexually active adolescents and young adults in Brazil: The POP-Brazil Study

For Brazil, there are no nationwide data on HPV prevalence against which the impact of the HPV immunization program can be measured in the future. Therefore, we aim to evaluate the prevalence of genital HPV infection among adolescents and young adults in Brazil. A cross-sectional, multicentric, nationwide survey was conducted between September 2016 and November 2017. Sexually active unvaccinated women and men aged 16 to 25 years old were recruited from 119 public primary care units, including all 26 state capitals and the Federal District. All participants answered a face-to-face interview and provided biological samples for genital HPV analysis. We used an automated DNA extraction method and HPV genotyping was performed using the Linear Array genotyping test (Roche). Of 7,694 participants, 53.6% (95% CI 51.4–55.8) were positive for any HPV type. The prevalence of high-risk HPV types was significantly higher in women (38.6% vs. 29.2%, P < 0·001). The HPV types included in the quadrivalent vaccine were detected in 1002 (14.8%) specimens, with a different pattern of HPV infection between sexes. Characteristics associated with overall HPV detection included female gender, self-declaration of race as brown/pardo, lower socioeconomic class, single or dating, current smoking and having 2 or more sex partners in the past year. We found a high prevalence of HPV, with significant differences between regions. Our data provide information that may be considered when developing HPV prevention policies and constitute a baseline against which the impact of the HPV immunization program in Brazil can be measured in future years.

Characteristics of human papillomaviruses distribution in Guizhou Province, China

BACKGROUND

Human papillomavirus (HPV) is one of the most common sexually transmitted viruses. Data about HPV infection in Guizhou is limited.

METHODS

56,768 cervical samples were collected and genotyped for 15 main high risk and 6 main low risk HPV types.

RESULTS

16.95% (9623/56768) of samples were HPV positive; 90.70% (8728/9623) of HPV positive women were infected by high risk HPV. High risk and high risk mix infection (1458; 70.85%) was the most common mix HPV infection type. The highest HPV detection rate was found in age group 41-45 years old (detection rate = 17.89%) (χ2 = 204.77; P < 0.001); the highest within-group HPV infection rates were found in the ≤20 (25.62%) and ≥ 61 (24.67%) years old age groups, the lowest within-group HPV infection rate was found in the 31-35 years old age group (15.02%). The highest mix infection proportions were found in the ≥61 (36.06%) and ≤ 20 (33.63%) years old age groups (χ2 = 111.21; P < 0.001), the lowest mix infection proportion was found in the 41-45 (17.42%) years old age group. The highest high risk infection proportions were found in the 26-30 (92.98%), ≥61 (92.68%), and 36-40 (92.16%) years old age groups (χ2 = 31.72; P < 0.001), the lowest high risk infection proportion was found in the ≤20 (84.96%) years old age group. HPV infection rates varied with seasons in Guizhou.

CONCLUSIONS

Characteristics of HPV distribution in Guizhou were identified. There were significant differences in HPV distribution among age groups, prevention strategies should be adjusted according to the characteristics.

Genetic variability of human papillomavirus type 66 L1 gene among women presenting for cervical cancer screening in Chile

The high-risk human papillomaviruses (HR-HPVs) are involved in the development of cervical cancer. Nevertheless, there are differences in the oncogenic potential among them. HPV-16 and HPV-18 are associated with approximately 70% of cancer worldwide, and both types are the most extensively studied HR-HPV. Great variations in the prevalence of HR-HPV have been described in different countries. The impact of these variations on the epidemiology of lesions and cervical cancer is currently unknown. A high prevalence of HPV-66 has been detected in Chile. Here, we have analyzed the genetic variability of the L1 gene from HPV-66-infected Chilean women. Higher order interactions between identified mutations were analyzed by co-variation and cluster analyses. Antigenic-index alterations following L1 mutations and B-cell epitopes were predicted by BcePred algorithm. HPV-66 L1 sequences clustered phylogenetically into two main clades. The genetic variability in the HPV-66 L1 gene involved thirty nucleotide changes. Four of these were for the first time identified in this study. Some of these variants are embedded in the B-cell epitope regions. Amino acid homology in the immunodominant epitopes of HPV-66 L1 protein (DE, FG and H1 loops) was 42.9-59.1% and 28.6-68.9% compared with HPV-16 and HPV-18, respectively. The results of this research suggest that the neutralizing epitopes of HPV-66 are antigenically different compared to HPV-16 and HPV-18. Our findings show the need to perform new structural and immunological studies on HPV-66 L1 protein to evaluate the cross-protection conferred by current HPV vaccines.

Population risk factors for late-stage presentation of cervical cancer in sub-Saharan Africa

BACKGROUND

Cervical cancer is the most prevalent malignancy in sub-Saharan Africa (SSA) with many women only seeking professional help when they are experiencing symptoms, implying late-stage malignancy and higher mortality rates. This ecological study assesses population-level exposures of SSA women to the numerous risk factors for HPV infection and cervical cancer, against late-stage presentation of cervical cancer.

MATERIALS AND METHOD

A literature review revealed the relevant risk factors in SSA. Open-access databases were mined for variables closely representing each risk factor. A proxy for late-stage presentation was used (ratio of incidence-to-mortality, IMR), and gathered from IARC's GLOBOCAN 2012 database. Variables showing significant correlation to the IMR were used in stepwise multiple regression to quantify their effect on the IMR.

RESULTS

Countries with high cervical cancer mortality rates relative to their incidence have an IMR nearer one, suggesting a larger proportion of late-stage presentation. Western Africa had the lowest median IMR (1.463), followed by Eastern Africa (IMR = 1.595) and Central Africa (IMR = 1.675), whereas Southern Africa had the highest median IMR (1.761). Variables selected for the final model explain 65.2% of changes seen in the IMR. Significant predictors of IMR were GDP (coefficient = 2.189 × 10^-6, p = 0.064), HIV infection (-1.936 × 10^-3, p = 0.095), not using a condom (-1.347 × 10^-3, p = 0.013), high parity (-1.744 × 10^-2, p = 0.008), and no formal education (-1.311 × 10^-3, p < 0.001).

CONCLUSION

Using an IMR enables identification of factors predicting late-stage cervical cancer in SSA including: GDP, HIV infection, not using a condom, high parity and no formal education.

Human papillomavirus genotype distribution among HPV-positive women in Sichuan province, Southwest China

In this hospital-based descriptive study, the genotype distribution of human papillomavirus (HPV) among HPV-infected women were investigated in 4,305 gynecological patients in Sichuan province. Females attending gynecology clinics between March 2014 and March 2015 were subjected to HPV screening after giving informed consent. Cervical scrapings were examined by cytopathology and colposcopy-directed biopsies. HPV genotyping was performed on a Luminex 200 system. Seventeen high-risk (HR) genotypes (HPV-16, -18, -31, -33, -35, -39, -45, -51, -52, -53, -56, -58, -59, -66, -68, -73, and -82) and seven low-risk (LR) genotypes (HPV-6, -11, -42, -43, -61, -81, and -83) were detected. Among all HPV-positive women, 34.1% (1,467/4,305) of the cases showed abnormal cytology and biopsy, including high-grade squamous lesions (HSIL), cervical intraepithelial neoplasias of grades 2 and 3 (CIN2/CIN3), and cervical cancer (CC). HPV-16, -52, and -58 were the predominant genotypes, followed by HPV-56, -18, -59, -39, -53, -33, and -81. A total of 3,785 (87.9%) HPV positive women were found to have HR HPV infection, while 859 (20.0%) were found to have LR HPV infection. Among all patients, 79% (3,401/4,305) were infected with a single strain of HPV, 85.5% (2,907/3,401) cases of which were of the HR HPV genotype. In cervical precancerous lesions (CPLs) and CC patients, HR HPV-16, -58, -52, -33, and -18 were the predominant genotypes. Interestingly, 33 CPL patients had a single LR HPV infection with HPV-61, -11, -81, -6, -43, or -42. Furthermore, one CC patient was infected only with LR HPV-11. According to the abundant genotype diversity of HPV in Sichuan, we suggest that a large-scale epidemiological investigation should be launched, not only to understand the distribution of HPV genotype, but also to provide information needed for HPV vaccination programs and to predict the effectiveness of current vaccines in Southwest China.

Characteristics of HPV prevalence in Sichuan Province, China

OBJECTIVE

To investigate the distribution of HPV subtypes and analyze variation in infection trends during a 6-year period in Sichuan Province, China.

METHODS

A cross-sectional observational study was conducted at a center in Chengdu between January 1, 2009, and December 31, 2014. Patients with at least one type of cervical disease confirmed by histology and cytology were eligible for inclusion. Cervical specimens were tested for the presence of high-risk and low-risk HPV subtypes by reverse membrane hybridization.

RESULTS

Among 10 682 participants, 3370 women (31.5%) were infected with HPV. The most frequently detected high-risk genotypes were HPV16 (n=791; 27.1%), HPV58 (n=476; 16.3%), HPV33 (n=273; 9.4%), HPV52 (n=244; 8.4%), and HPV18 (n=201; 6.9%). The most frequently detected low-risk genotype was HPV6 (n=703; 40.8%). The detection rates of HPV33 (from 7.9% to 10.2%) and HPV58 (from 14.0% to 16.7%) increased over the 6-year period, whereas those of HPV16 (from 32.3% to 24.9%) and HPV18 (from 10.0% to 6.2%) decreased. The prevalence of HPV infection was highest among women aged 21-25 years (χ(2)=191.189; P<0.001).

CONCLUSION

HPV58 and HPV33 were the most prevalent subtypes in Sichuan. Changes in the prevalences of infection with different HPV subtypes have been identified.

Decreased HPV-specific T cell responses and accumulation of immunosuppressive influences in oropharyngeal cancer patients following radical therapy

Oropharyngeal cancer (OPC) is a type of squamous cell head and neck cancer that is often associated with human papillomavirus (HPV) infection, suggesting the potential for immunotherapeutic targeting of HPV antigens. This study aimed to determine the effect of radical therapy on HPV-specific T cells and other immune parameters in 20 OPC patients, as a prelude to future immunotherapy studies. HPV DNA could be detected in 9/12 available tissue samples (8/9 HPV(+) samples were also p16(+)). HPV-specific T cell responses against HPV16 E6 and E7 peptides were detected by enzyme-linked immunoSPOT in 10/13 and 8/13 evaluable patients, respectively, but did not appear to correlate with HPV status. Post-treatment, both HPV E6 and E7 T cell responses were decreased (4/13 and 2/13 patients, respectively). These reductions in T cell response could not be explained by a concurrent decrease in memory T cells whose absolute numbers were relatively unaffected by radical therapy (27,975 vs. 25,661/10(5) PBMC) despite a significant decrease in overall lymphocyte counts (1.74 vs. 0.69 × 10(9)/L). Instead, there were significant increases in regulatory T cells (3.7 vs. 6.8 %) and a population of myeloid-derived suppressor cells (CD14(-)HLA-DR(-)CD15(hi), 12.38 vs. 21.92 %). This suggests that immunosuppression may contribute to the reduction in HPV-specific T cell responses post-treatment, although study of larger patient cohorts will be required to test whether this affects clinical outcome. Overall these findings suggest that HPV-targeted immunotherapy in post-therapy OPC patients will require multiple strategies to boost T cell immunity and to overcome the influence of immunosuppressive cells.

Prevalence of human papillomavirus in university young women

Cervical cancer is the second most prevalent female cancer worldwide. The majority of cases appear between the age of 30 and 50. Human papillomavirus (HPV) plays a central role in cervical cancer with 99.7% of HPV DNA identified in invasive cervical carcinomas. The prevalence of the HPV infection varies substantially among countries and according to age and lifestyle. HPV is a common sexually transmitted infection among males and females with a 70% higher incidence in sexually active females. This study aimed to determine the prevalence of human papillomavirus in young university women by analyzing the correlation between Papanicolaou (PAP)-stained cervical tests and HPV detection by genotyping, as well as other risk factors. A total of 200 women aged between 18 and 25 years were enrolled in this study, which took place between September 2008 and May 2009 at the Universidad de Tarapacá, Arica, Chile. Results of the PAP smears showed that 97.5% of cells had normal characteristics, although an inflammatory pattern was noted. The prevalence of generic HPV infection was 3.5% when testing for HPV DNA using the polymerase chain reaction (PCR) method. An analysis of the genotype of infected female individuals indicated that high-risk HPV types, such as HPV 16 and 31 were present in 42.84 and 14.29% of females, respectively, and low-risk types such as HPV 6, in 14.29%. Only one sample with differentiated non-HPV (14.29%) was found. A 95% correlation between PAP-stained cervical tests and the method of testing for HPV was observed. Using the PCR method, it was found that of the 195 negative PAP smears, 5 were positive for HPV and two of the samples that were positive for ASC-US were also positive. A significantly increased (P<0.05) HPV infection risk was observed in the 18-21 age group with a higher prevalence (71.40%) when compared to the 22-25 age group (28.6%). A significant (P<0.042) difference was found between smoking and HPV infection. In conclusion, a significant (P<0.05) correlation was found between PAP and PCR methods for HPV testing in young university women. A significant correlation between smoking and HPV was detected, whereas no difference was noted with other parameters.

Risk factors for high-risk human papillomavirus infection and cofactors for high-grade cervical disease in Peru

OBJECTIVE

To evaluate the association between potential risk factors for high-risk human papillomavirus (HR-HPV) infection and cofactors for cervical intraepithelial lesions grade 2 or worse (CIN2+) in women attending cervical screening in Amazonian Peru.

MATERIALS AND METHODS

Participants completed a risk factor questionnaire before screening. High-risk human papillomavirus infection was determined by Hybrid Capture II. Logistic regression was used to evaluate associations between potential risk factors for HR-HPV infection and between cofactors and risk of CIN2+ among women with HR-HPV infection.

RESULTS

Screening and questionnaires were completed by 5435 women aged 25 to 49 years. The prevalence of HR-HPV was 12.6% (95% confidence interval [CI], 11.8%-13.6%) and decreased by age. Early age at first sexual intercourse and several lifetime sexual partners increased the risk of having HR-HPV (age-adjusted odds ratio [AOR] of age at first sexual intercourse <18 vs ≥20, 1.5; 95% CI, 1.2-2.0; AOR of ≥5 lifetime sexual partners vs 1, 2.1; 95% CI, 1.4-3.2). Among women with HR-HPV infection, those with no schooling (AOR relative to 1-5 years of schooling, 3.2; 95% CI, 1.3-8.3) and those with parity ≥3 (AOR relative to parity <3, 2.6; 95% CI, 1.4-4.9) were at increased risk of CIN2+. The effect of parity was stronger for cancer (AOR of parity ≥3 vs <3, 8.3; 95% CI, 1.0-65.6). Further analysis showed that the association between parity and CIN2+ was restricted to women younger than 40. Most women (83%) had previously been screened. Sixty-four percent of CIN2+ cases detected in this study occurred in women who reported having had a Papanicolaou test in the previous 3 years. Only 4 of 20 cancers were detected in women never screened before. Having had a previous abnormal Papanicolaou test increased the risk of CIN2+ (OR, 16.1; 95% CI, 6.2-41.9).

CONCLUSION

Among women with HR-HPV, high parity (in young women), no schooling, lack of good-quality screening and of adequate follow-up care are the main risk factors for high-grade cervical disease in Peru.

Prevalence and genotype characterization of human papillomaviruses among HIV-seropositive in Ouagadougou, Burkina Faso

BACKGROUND

Approximately, 15-20 of 40 HPVs that infect the female genital tract confer a high-risk of invasive cancer, thus HPVs account for 95% of cervix cancers. The objectives of this study were to: (i) estimate the prevalence of HPV infection in women infected with HIV in Ouagadougou, (ii) identify potential carcinogenic HPV strains and (iii) determine whether existing HPV vaccines match the isolated strains.

METHODS

From May 2009 to April 2010, 250 HIV-infected women were included in this study. Each woman was screened for the presence of HPV and for HPV genotype using PCR/hybridization technique.

RESULTS

Of the 250 HIV-infected women, 59.6% were infected with at least one type of HPV. High-risk HPVs were identified with the following prevalence: HPV-18 (25.0%); HPV-50'S (25.5%); HPV-30'S (20.8%); HPV-16 (4.7%); HPV-45 (3.7%). Low-risk HPVs were represented by HPV-6 (5.7%) and HPV-11 (0.9%).

CONCLUSION

The issue of the study showed that the existing vaccines: Gardasil and Cervarix may be used in the country although they match only HPV-16, HPV-18, HPV-6 and HPV-11. Further investigations should be continued for the establishment of vaccine that matches all genotypes circulating in the country.

The role of human papillomavirus testing in the management of women with low-grade abnormalities: multicentre randomised controlled trial

OBJECTIVE

To assess the value of a single human papillomavirus (HPV) test in making decisions on management of women with cervical cytology showing borderline nuclear abnormality (BNA) or mild dyskaryosis. In particular, to determine whether information on high-risk (hr) HPV status would be valuable in the choice between (1) cytological surveillance versus immediate referral to colposcopy, and (2) at colposcopy, between biopsy and recall versus immediate large loop excision of the transformation zone (LLETZ).

DESIGN

Multicentre individually randomised controlled trial, nested within the NHS Cervical Screening Programmes, investigating the value of HPV testing by testing for interactions between HPV status and (1) cytological surveillance versus colposcopy, and (2) biopsy and recall versus immediate LLETZ. Setting Grampian, Tayside and Nottingham. Population Women (n = 4439), aged 20-59 years, with a cytology test showing borderline nuclear abnormalities or mild dyskaryosis during October 1999 to October 2002.

METHODS

High-risk HPV status was determined at recruitment using the polymerase chain reaction assay with the GP5+/6+ general primer system. The results of this HPV testing were not disclosed to either the participating women or to those involved in their management. Women were randomised to either (1) 6-monthly cytological screening in primary care or (2) referral for colposcopy. Human papillomavirus status was used to stratify both randomisations. All women were followed for 3 years, concluding with an invitation to an exit appointment at which colposcopic examination was undertaken. In addition, in women who were randomised to initial colposcopy and underwent colposcopy, the association between hrHPV status and presence of cervical intraepithelial neoplasia (CIN) grade 2 or more severe disease (henceforth CIN2 or worse) was examined.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive values of the HPV test for predicting CIN2 or worse and the implications for the choice of management between cytological surveillance and immediate referral for colposcopy.

RESULTS

There were no significant interactions between management and HPV status. Hence, in women with mild dyskaryosis or BNA who are HPV positive, there is no advantage of (1) immediate colposcopy over cytological surveillance (P = 0.76) or (2) immediate LLETZ over biopsy and recall (P = 0.27). The sensitivity of HPV testing for detection of CIN2 or worse was 75.2% (95% CI 68.8-81.0%) among women with mild dyskaryosis and 69.9% (95% CI 61.7-77.3%) among those with BNA. Specificity was higher in those with BNA (71.3%; 95% CI 68.5-74.1%) than in those with mild dyskaryosis (46.9%; 95% CI 42.2-51.6%). Sensitivity decreased with increasing age whereas specificity increased. The negative predictive value was high, particularly among women with BNA (94.5%; 95% CI 92.9-96.0%). Across all ages, 22% of women who had CIN2 or worse were HPV negative. Conversely, 40% of those who were HPV positive did not have CIN. HPV was a much more reliable predictor in women aged over 40 years.

CONCLUSIONS

We conclude that in younger women with low-grade cytological abnormalities, a single HPV test would not be useful in determining who should be referred for colposcopy or the most effective management at colposcopy. In women over 40, a negative HPV test could be used to rule out further investigation.

Human papillomavirus infection in Beijing, People's Republic of China: a population-based study

Background:

No recent data exist on human papillomavirus (HPV) infection in Beijing, People's Republic of China.

Materials and method

We interviewed and examined a representative, randomly selected sample of 5552 sexually active women aged 25–54 years. Cervical cell samples were analysed for HPV DNA by a MY09/11-based PCR assay.

Results:

Human papillomavirus prevalence was 6.7% overall and 4.8% among women without cervical abnormalities. Of the 21 subtypes identified, HPV16 was the commonest type (2.6% overall; 39.1% of HPV-positive women), followed by HPV 58 (1.0%), 33 (0.8%), 43 (0.7%) and 56 (0.7%). High-risk HPV types predominated in all age groups. Human papillomavirus prevalence was highest in young to middle-aged women. Marital status, number of husband's sexual partners, age at sexual debut and nulligravidity were all associated with being HPV positive.

Conclusions:

In our survey, HPV 16, HPV 58 and HPV 33 were the most prevalent HPV types in Beijing, indicating the potential for the prophylactic HPV 16/18 vaccine in China.

Human papillomavirus--lessons from history and challenges for the future

Human papillomavirus (HPV) is the most common sexually transmitted infection, and HPV-associated cervical cancer is a significant cause of morbidity and mortality worldwide. Recent advances in molecular biology have facilitated testing for HPV infection. Over the last decade, national and international cervical cancer screening programs have added HPV testing to their guidelines. The use of HPV prophylactic and therapeutic immunization may expand the need for systematic HPV testing to help define eligible subgroups for intervention. Given the worldwide variation in HPV subtype prevalence, basic Pap testing will continue to play an important role in cervical cancer screening, and methods to improve Pap smear sensitivity may help to improve screening in the future. This review focuses on the genetics and cellular biology of HPV infection, the natural history and prevalence of HPV infections, cervical cancer screening around the world and in Canada in particular, and evolving research to improve screening methods.

Epidemiology of Human Papilloma Virus (HPV) in Cervical Mucosa

In a worldwide scenario, human papillomavirus (HPV) infection is the second leading cause of cancer-related morbidity and mortality among women due to its very close association with cervical cancer. More than 100 different types of HPV genotypes have been characterized to date. Among these, approximately 24 HPV genotypes specifically infect the genital and oral mucosal system. The mucosal HPVs are most frequently sexually transmitted, and they are responsible for the most common sexually transmitted diseases throughout the world. In a majority of the cases, oncogenic/nononcogenic HPV infections spontaneously clear by themselves without any medical intervention. However, a persistent and long-term HPV infection usually leads to cervical cancer, which remains difficult to treat. In recent years, advance understanding of the structure of HPV and its pathogenesis has led to a variety of new treatments to combat HPV-related diseases, including a Food and Drug Administration-approved HPV vaccine that is very effective in young women. To effectively use this HPV vaccine worldwide, a clear understanding of HPV genotypes in different geographical populations is imperative. In this chapter, we have focused briefly on HPV genotypes and HPV prevalence in the women of different geographical populations.

Human papillomavirus prevalence in women attending routine cervical screening in South Wales, UK: a cross-sectional study

In this cross-sectional population-based study we determine human papillomavirus (HPV) prevalence in South Wales to provide comprehensive baseline data for future assessment of the impact of prophylactic HPV vaccination and to help inform future screening strategies. Liquid-based cytology samples from women attending routine cervical screening were collected (n=10 000: mean age 38 years, 93% cytology negative, and 64.8% from the 50% least deprived LSOA according to social deprivation score (SDS)). High-Risk (HR) and Low-Risk HPV screening was performed using HPV PCR-EIA with genotyping of HR positives and data correlated with age, SDS and cytology. Overall HPV prevalence was 13.5% (9.3% age standardised) and the most frequent HR types were HPV 16, 31, 18 and 58. In HR HPV-positive cases 42.4% had a single HR type and they were predominant in women with severe cytological abnormalities. Here, 66% of all HR HPV cases were in women aged 30 years of age or less and SDS had no significant effect on HPV status. HPV prevalence increased significantly with degree of dyskarosis from 7% in cytology negative samples to 80% in samples with severe cytological abnormalities (P-value <0.0001). Overall, 46% of HR HPV cases were positive for the two HR types targeted by the prophylactic vaccines (HPV 16 and HPV 18). The data presented represents the largest type-specific investigation of HPV prevalence in an unselected UK population.

Human papillomavirus infection in Barrett's oesophagus in the UK: an infrequent event

BACKGROUND

Human papillomavirus (HPV) infection has been reported in squamous cell carcinomas of the oesophagus and has been recently described in Barrett's oesophagus, a premalignant condition which may give rise to oesophageal adenocarcinoma.

OBJECTIVES

To investigate HPV infection in Barrett's oesophagus in a UK population.

STUDY DESIGN

DNA was extracted from 73 Barrett's oesophagus biopsies and examined for the presence of DNA for 14 high risk (HR) and 6 low risk (LR) HPV types.

RESULTS

HPV DNA was present in only 1 of 73 samples; genotyping indicated this was a high risk type 51 infection.

CONCLUSIONS

HPV infection appears unlikely to be a significant factor in the aetiology of Barrett's oesophagus in the UK.

Lifestyle and socio-demographic factors associated with high-risk HPV infection in UK women

The world age-standardised prevalence of high-risk HPV (hrHPV) infection among 5038 UK women aged 20–59 years, with a low-grade smear during 1999–2002, assessed for eligibility for TOMBOLA (Trial Of Management of Borderline and Other Low-grade Abnormal smears) was 34.2%. High-risk HPV prevalence decreased with increasing age, from 61% at ages 20–24 years to 14–15% in those over 50 years. The age-standardised prevalence was 15.1, 30.7 and 52.7%, respectively, in women with a current normal, borderline nuclear abnormalities (BNA) and mild smear. In overall multivariate analyses, tertiary education, previous pregnancy and childbirth were associated with reduced hrHPV infection risk. Risk of infection was increased in non-white women, women not married/cohabiting, hormonal contraceptives users and current smokers. In stratified analyses, current smear status and age remained associated with hrHPV infection. Data of this type are relevant to the debate on human papillomavirus (HPV) testing in screening and development of HPV vaccination programmes.

Variation in human papillomavirus type-16 viral load within different histological grades of cervical neoplasia

The objective of this study was to investigate variation in human papillomavirus (HPV) type-16 load within histologically defined grades of cervical intraepithelial neoplasia. Two hundred and thirty-seven liquid based cytology samples were collected from women attending colposcopy clinics, DNA was extracted, and presence of virus determined by PCR-enzyme immunoassay. Quantitative real-time PCR was used to determine viral load for 70 HPV-16 positive single infections. Viral load was expressed as the ratio of copies of the viral L1 gene to copies of the human beta-globin gene. Measurements varied from 0.019 to 4,194 HPV genomes per cell. Our data demonstrate that in cervical neoplasia, HPV load tends to correlate with disease severity, but that the number of viral genomes/cell varies considerably within histological grades. This variation within disease grades currently limits the clinical utility of viral load measurement.