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1.  Human Papillomavirus Genotype Distributions: Implications for Vaccination and Cancer Screening in the United States 
Background
Limited data are available describing human papillomavirus (HPV) genotype distributions in cervical cancer in the United States. Such studies are needed to predict how HPV vaccination and HPV-based screening will influence cervical cancer prevention.
Methods
We used the New Mexico Surveillance, Epidemiology, and End Results Registry to ascertain cases of in situ (n = 1213) and invasive (n = 808) cervical cancer diagnosed during 1985–1999 and 1980–1999, respectively, in the state of New Mexico. HPV genotyping was performed using two polymerase chain reaction–based methods on paraffin-embedded tissues from in situ and invasive cancers and on cervical Papanicolaou test specimen from control subjects (ie, women aged 18–40 years attending clinics for routine cervical screening [n = 4007]). Relative risks for cervical cancer were estimated, and factors associated with age at cancer diagnosis and the prevalence of HPV genotypes in cancers were examined.
Results
The most common HPV genotypes detected in invasive cancers were HPV type 16 (HPV16, 53.2%), HPV18 (13.1%), and HPV45 (6.1%) and those in in situ cancers were HPV16 (56.3%), HPV31 (12.6%), and HPV33 (8.0%). Invasive cancer case subjects who were positive for HPV16 or 18 were diagnosed at younger ages than those who were positive for other carcinogenic HPV genotypes (mean age at diagnosis: 48.1 [95% confidence interval {CI} = 46.6 to 49.6 years], 45.9 [95% CI = 42.9 to 49.0 years], and 52.3 years [95% CI = 50.0 to 54.6 years], respectively). The proportion of HPV16-positive in situ and invasive cancers, but not of HPV18-positive cancers, declined with more recent calendar year of diagnosis, whereas the proportion positive for carcinogenic HPV genotypes other than HPV18 increased.
Conclusions
HPV16 and 18 caused the majority of invasive cervical cancer in this population sample of US women, but the proportion attributable to HPV16 declined over the last 20 years. The age at diagnosis of HPV16- and HPV18-related cancers was 5 years earlier than that of cancers caused by carcinogenic HPV genotypes other than HPV16 and 18, suggesting that the age at initiation of cervical screening could be delayed in HPV-vaccinated populations.
doi:10.1093/jnci/djn510
PMCID: PMC2664090  PMID: 19318628
2.  Genotypic distribution of human papillomavirus (HPV) and cervical cytology findings in 5906 Thai women undergoing cervical cancer screening programs 
Background
Cervical cancer is the major cause of morbidity and mortality in Thai women. Nevertheless, the preventive strategy such as HPV vaccination program has not been implemented at the national level. This study explored the HPV prevalence and genotypic distribution in a large cohort of Thai women.
Methods
A hospital-based cervical cancer screening program at Chulabhorn Hospital, Bangkok and a population-based screening program at a rural Pathum Thani Province were conducted using liquid-based cytology and HPV genotyping.
Results
Of 5906 women aged 20–70 years, Pap smear was abnormal in 4.9% and the overall HPV prevalence was 15.1%, with 6.4% high-risk (HR), 3.5% probable high-risk (PR), and 8.4% low-risk (LR) HPV. The prevalence and genotypic distribution were not significantly different between the two cohorts. Among HR-HPV genotypes, HPV52 was the most frequent (1.6%), followed by HPV16 (1.4%), HPV51 (0.9%), HPV58 (0.8%), HPV18 (0.6%), and HPV39 (0.6%). Among LR-HPV genotypes, HPV72 and HPV62 were the most frequent while HPV6 and HPV11 were rare. HPV infection was found to be proportionately high in young women, aged 20–30 years (25%) and decreasing with age (11% in women aged >50). The more severe abnormal cytology results, the higher positivity of HR-HPV infection was observed.
Conclusions
In conclusion, HPV52, HPV16, and HPV51 were identified as the most common HR-HPV genotypes in Thai women. This study contributes genotypic evidence that should be essential for the development of appropriate HPV vaccination program as part of Thailand’s cervical cancer prevention strategies.
doi:10.1186/s13027-015-0001-5
PMCID: PMC4347911  PMID: 25737740
Cervical cancer; Cancer screening; HPV genotypes; Cervical cytology; Thailand
3.  Human papillomavirus infections in women seeking cervical Papanicolaou cytology of Durango, Mexico: prevalence and genotypes 
Background
HPV infection in women from developing countries is an important public health problem. Therefore, we sought to determine the prevalences of HPV infection and HPV genotypes in a female population of Durango City, Mexico. Also to determine whether any socio-demographic characteristic from the women associated with HPV infection exists.
Methods
Four hundred and ninety eight women seeking cervical Papanicolaou examination in three public Health Centers were examined for HPV infection. All women were tested for HPV DNA PCR by using HPV universal primers. In addition, all positive HPV DNA PCR samples were further analyzed for genotyping of HPV genotype 16, 18 and 33. Socio-demographic characteristics from each participant were also obtained.
Results
Twenty-four out of four hundred and ninety-eight (4.8%) women were found infected by HPV. HPV genotype 16 was found in 18 out of the 24 (75%) infected women. Two of them were also coinfected by HPV genotype 18 (8.3%). In the rest 6 PCR positive women, genotyping for HPV genotypes 16, 18 and 33 were negative.
Conclusion
The prevalence of HPV in women of Durango City is low; however, most infected women have high risk HPV genotype. The women who were studied showed low frequency of risk factors for HPV infection and this may explain the low prevalence of HPV infection. The high frequency of high risk HPV genotypes observed might explain the high rate of mortality for cervical cancer in our region.
doi:10.1186/1471-2334-6-27
PMCID: PMC1388223  PMID: 16504014
4.  Prevalence and Molecular Epidemiology of Human Papillomavirus Infection in Italian Women with Cervical Cytological Abnormalities 
Background
Human papillomavirus (HPV) infection is the most common sexually transmitted infection and high-risk HPV types are a necessary cause for the development of cervical cancer. The present study investigated the HPV-type specific prevalence in 650 women, aged 15-76 years, with cytological abnormalities and the association between HPV infection and cervical disease in a subset of 160 women for whom cytological results for Pap-Test were available, during the period 2008-2011 in Cagliari (Southern Italy).
Design and Methods
HPV-DNA extraction was performed by lysis and digestion with proteinase K and it was typed by using the INNOLiPA HPV Genotyping Assay.
Results
Overall the HPV prevalence was 52.6%; high-risk genotypes were found in 68.9% of women and multiple-type infection in 36.1% of HPV-positive women. The commonest types were HPV-52 (23.4%), HPV-53 (15.7%), HPV-16 (15.4%) and HPV-6 (12.4%). Among the women with cytological diagnosis, any-type of HPV DNA was found in 49.4% of the samples and out of these 93.7% were high-risk genotypes. Genotype HPV 53 was the commonest type among women affected by ASCUS lesions (21.4%), genotype 52 in positive L-SIL cases (22.5%), genotype 16 H-SIL (27.3%).
Conclusions
This study confirmed the high prevalence of HPV infection and high-risk genotypes among women with cervical abnormalities while, unlike previously published data, genotype HPV-52 was the most common type in our series. These data may contribute to increase the knowledge of HPV epidemiology and designing adequate vaccination strategies.
Significance for public healthHuman papillomavirus (HPV) is the most common sexually-transmitted agent, which can cause cervical lesions and cancer in females. Efforts to reduce the burden of cervical cancer with cytology screening in the last years have had limited success. HPV infection and disease imposes a substantial burden of direct costs on the Italian National Health Service that have never been fully quantified. Monitoring HPV prevalence could represent a tool to follow the evolution of the infection in the vaccination and post-vaccination era, to understand the impact of HPV types in cervical diseases in Italy. Our survey shows an high frequency of infections sustained by HPV 52. Given the recent implementation of a widespread immunization program with vaccines not containing HPV 52, it has been relevant to prove the high prevalence of this HPV genotype from the beginning of the vaccination campaign, to avoid ascribing to the vaccination program a possible selection effect and the importance of non-vaccine HPV types in the burden of cervical disease, in order to assess the opportunity to realize new vaccine including other types.
doi:10.4081/jphr.2014.157
PMCID: PMC4140382  PMID: 25170506
HPV epidemiology; cervical abnormalities; HPV prevalence
5.  Prevalence and distribution of high-risk human papilloma virus (HPV) types in invasive squamous cell carcinoma of the cervix and in normal women in Andhra Pradesh, India 
Background
Despite the high incidence of cervical cancer reported from India, large scale population based studies on the HPV prevalence and genotype distribution are very few from this region. In view of the clinical trials for HPV vaccine taking place in India, it is of utmost importance to understand the prevalence of HPV genotypes in various geographical regions of India. We investigated the genotype distribution of high-risk HPV types in squamous cell carcinomas and the prevalence of high-risk HPV in cervicovaginal samples in the southern state of Andhra Pradesh (AP), India.
Methods
HPV genotyping was done in cervical cancer specimens (n = 41) obtained from women attending a regional cancer hospital in Hyderabad. HPV-DNA testing was also done in cervicovaginal samples (n = 185) collected from women enrolled in the cervical cancer screening pilot study conducted in the rural community, of Medchal Mandal, twenty kilometers away from Hyderabad.
Results
High-risk HPV types were found in 87.8% (n = 36/41) of the squamous cell carcinomas using a PCR-based line blot assay. Among the HPV positive cancers, the overall type distribution of the major high-risk HPV types was as follows: HPV 16 (66.7%), HPV 18 (19.4%), HPV 33 (5.6%), HPV 35 (5.6%), HPV 45 (5.6%), HPV 52 (2.8%), HPV 58(2.8%), HPV 59(2.8%) and HPV 73 (2.8%). Women participating in the community screening programme provided both a self-collected vaginal swab and a clinician-collected cervical swab for HPV DNA testing. Primary screening for high risk HPV was performed using the Digene Hybrid Capture 2 (hc2) assay. All hc2 positive samples by any one method of collection were further analyzed using the Roche PCR-based line blot for genotype determination. The prevalence of high risk HPV infection in this community-based screening population was 10.3% (19/185) using the clinician-collected and 7.0% (13/185) using the self-collected samples. The overall agreement between self-collected and clinician-collected samples was 92%; however among HPV-positive specimens, the HPV agreement was only moderate (39.1%). The most frequently detected HPV types in the Medchal community are HPV 52 and 16.
Conclusion
Our results suggest that the HPV type distribution in both cervical cancer tissues and in a general screening population from Andhra Pradesh is similar to that reported in India and other parts of the world. We also conclude that an effective vaccine targeting HPV 16 will reduce the cervical cancer burden in AP.
doi:10.1186/1471-2334-5-116
PMCID: PMC1345691  PMID: 16371167
6.  Prevalence of human papillomavirus infection in women in Benin, West Africa 
Virology Journal  2011;8:514.
Background
Cervical cancer ranks as the first most frequent cancer among women in Benin. The major cause of cervical cancer now recognized is persistent infection of Human Papillomavirus (HPV). In Benin there is a lack of screening programs for prevention of cervical cancer and little information exists regarding HPV genotype distribution.
Methods
Cervical cells from 725 women were examined for the presence of viral DNA by means of a polymerase chain reaction (PCR) multiplex-based assay with the amplification of a fragment of L1 region and of E6/E7 region of the HPV genome, and of abnormal cytology by Papanicolaou method. The association between HPV status and Pap test reports was evaluated. Socio-demographic and reproductive characteristics were also related.
Results
A total of 18 different HPV types were identified, with a prevalence of 33.2% overall, and 52% and 26.7% among women with and without cervical lesions, respectively. Multiple HPV infections were observed in 40.2% of HPV-infected women. In the HPV-testing group, the odds ratio for the detection of abnormal cytology was 2.98 (95% CI, 1.83-4.84) for HPV positive in comparison to HPV negative women. High risk types were involved in 88% of infections, most notably HPV-59, HPV-35, HPV-16, HPV-18, HPV-58 and HPV-45. In multiple infections of women with cytological abnormalities HPV-45 predominated.
Conclusions
This study provides the first estimates of the prevalence of HPV and type-specific distribution among women from Benin and demonstrates that the epidemiology of HPV infection in Benin is different from that of other world regions. Specific area vaccinations may be needed to prevent cervical cancer and the other HPV-related diseases.
doi:10.1186/1743-422X-8-514
PMCID: PMC3231975  PMID: 22074103
human papillomavirus; cervical cancer; Benin; Pap test; prevention
7.  Nationwide prevalence of human papillomavirus infection and viral genotype distribution in 37 cities in China 
BMC Infectious Diseases  2015;15:257.
Background
Type-specific high-risk HPV (hrHPV) infection is related to cervical carcinogenesis. The prevalence of hrHPV infection varies geographically, which might reflect the epidemiological characteristics of cervical cancer among different populations. To establish a foundation for HPV-based screening and vaccination programs in China, we investigated the most recent HPV prevalence and genotypic distributions in different female age groups and geographical regions in China.
Methods
In 2012, a total of 120,772 liquid-based cytological samples from women enrolled for population- or employee-based cervical screening in 37 Chinese cities were obtained by the Laboratory of Molecular Infectious Diseases of Guangzhou KingMed. A total of 111,131 samples were tested by Hybrid Capture II and the other 9,641 were genotyped using the Tellgenplex™ HPV DNA Assay.
Results
The total positive rate for hrHPV was 21.07 %, which ranged from 18.42 % (Nanchang) to 31.94 % (Haikou) and varied by region. The regions of Nanchang, Changsha, Hangzhou, Chengdu, Fuzhou, Guangdong, and Guiyang could be considered the low prevalence regions. Age-specific prevalence showed a “two-peak” pattern, with the youngest age group (15–19 years) presenting the highest hrHPV infection rate (30.55 %), followed by a second peak for the 50–60-year-old group. Overall, the most prevalent genotypes were HPV16 (4.82 %) and HPV52 (4.52 %), followed by HPV58 (2.74 %). Two genotypes HPV6 (4.01 %) and HPV11 (2.29 %) were predominant in the low-risk HPV (lrHPV) type, while the mixed genotypes HPV16 + 52 and HPV52 + 58 were most common in women with multiple infections.
Conclusions
This study shows that HPV infection in China has increased to the level of an “HPV-heavy-burden” zone in certain regions, with prevalence varying significantly among different ages and regions. Data from this study represent the most current survey of the nationwide prevalence of HPV infection in China, and can serve as valuable reference to guide nationwide cervical cancer screening and HPV vaccination programs.
Electronic supplementary material
The online version of this article (doi:10.1186/s12879-015-0998-5) contains supplementary material, which is available to authorized users.
doi:10.1186/s12879-015-0998-5
PMCID: PMC4491249  PMID: 26142044
Human papillomavirus; hrHPV prevalence; HPV genotyping; Cervical cancer; China
8.  Human Papillomavirus (HPV) infection in pregnant women and mother-to-child transmission of genital HPV genotypes: a prospective study in Spain 
Background
Studies on HPV infection in pregnant women and HPV transmission to the child have yielded inconsistent results.
Methods
To estimate mother-to-child HPV transmission we carried out a prospective cohort study that included 66 HPV-positive and 77 HPV-negative pregnant women and their offspring attending a maternity hospital in Barcelona. To estimate HPV prevalence and genotype distribution in pregnancy we also carried out a related screening survey of cervical HPV-DNA detection among 828 pregnant women. Cervical cells from the mother were collected at pregnancy (mean of 31 weeks) and at the 6-week post-partum visit. Exfoliated cells from the mouth and external genitalia of the infants were collected around birth, at the 6-week post-partum visit, and around 3, 6, 12, and 24 months of age. All samples were tested for HPV using PCR. Associations between potential determinants of HPV infection in pregnant women and of HPV positivity in infants were also explored by logistic regression modelling.
Results
Overall cervical HPV-DNA detection in pregnant women recruited in the HPV screening survey was 6.5% (54/828). Sexual behavior-related variables, previous histories of genital warts or sexually transmitted infections, and presence of cytological abnormalities were statistically significantly and positively associated with HPV DNA detection in pregnant women recruited in the cohort. At 418 infant visits and a mean follow-up time of 14 months, 19.7% of infants born to HPV-positive mothers and 16.9% of those born to HPV-negative mothers tested HPV positive at some point during infants' follow-up. The most frequently detected genotype both in infants and mothers was HPV-16, after excluding untyped HPV infections. We found a strong and statistically significant association between mother's and child's HPV status at the 6-week post-partum visit. Thus, children of mothers' who were HPV-positive at the post-partum visit were about 5 times more likely to test HPV-positive than children of corresponding HPV-negative mothers (p = 0.02).
Conclusion
This study confirms that the risk of vertical transmission of HPV genotypes is relatively low. HPV persistence in infants is a rare event. These data also indicate that vertical transmission may not be the sole source of HPV infections in infants and provides partial evidence for horizontal mother-to-child HPV transmission.
doi:10.1186/1471-2334-9-74
PMCID: PMC2696457  PMID: 19473489
9.  Type- and age-specific distribution of human papillomavirus in women attending cervical cancer screening in Finland 
British Journal of Cancer  2013;109(11):2941-2950.
Background:
Large-scale data on type-specific HPV prevalences and disease burden are needed to monitor the impact of HPV vaccination and to plan for HPV-based cervical screening.
Methods:
33 043 women (aged 25–65) were screened for HPV by a Hybrid Capture 2 (HC2) in a population-based programme. HPV-positive women (n=2574) were triaged by cytology and HPV genotyped using PCR-Luminex. Type-specific prevalence of HPV infection and its correlation to findings in cytology triage and histology as well as Population Attributable Fractions for a referral to colposcopy and findings in histology were calculated.
Results:
Among HC2-positive women, 61.5% had normal, 23.1% had ASC-US and 15.5% had LSIL or more severe (LSIL+) results in cytology. Out of HC2-positive samples, 57% contained the 13 Group 1/2A HPV types, which were targeted by the HC2, 15% contained Group 2B types, 8.5% Group 3 types and 30% were found to be negative in HPV genotyping. The proportion of samples positive for HPV by the HC2, but negative in HPV genotyping increased with age and decreased with increasing cytological abnormality. The most frequent types were HPV 16 (0.9% of screened women and 12.1% of the HC2-positive women), HPV 31 (0.7% and 8.9%, respectively) and HPV 52 (0.5% and 6.3%, respectively). The prevalence of Group 1/2A HPV types increased with increasing CIN grade and attributed 78.3% (95% CI 53.4–89.9) of the CIN 3+ lesions, while HPV 16 attributed 55.8% (40.0–67.5) of them.
Conclusion:
The type-specific prevalence of HPV were slightly lower than the average in international meta-analyses. Genotyping for HPV 16 better identified women with CIN 3+ than cytology triage at the threshold of LSIL+. The high proportion of women that were HC2-positive but HPV-negative in genotyping suggests that HPV genotyping may be useful also for validation of results in HPV screening. The large-scale HPV genotyping data were found to be directly useful for planning further preventive efforts for cervical cancer.
doi:10.1038/bjc.2013.647
PMCID: PMC3844908  PMID: 24136148
human papillomavirus; HPV prevalence; HPV types; HPV screening; HPV genotyping; age
10.  Primary Screening for Cervical Cancer Based on High-Risk Human Papillomavirus (HPV) Detection and HPV 16 and HPV 18 Genotyping, in Comparison to Cytology 
PLoS ONE  2015;10(3):e0119755.
Objectives
The objective of the present study is to assess the performance of a high-risk human papillomavirus (HR-HPV) DNA test with individual HPV-16/HPV-18 genotyping as a method for primary cervical cancer screening compared with liquid-based cytology (LBC) in a population of Greek women taking part in routine cervical cancer screening.
Methods
The study, conducted by the “HEllenic Real life Multicentric cErvical Screening” (HERMES) study group, involved the recruitment of 4,009 women, aged 25–55, who took part in routine cervical screening at nine Gynecology Departments in Greece. At first visit cervical specimens were collected for LBC and HPV testing using the Roche Cobas 4800 system. Women found positive for either cytology or HPV were referred for colposcopy, whereas women negative for both tests will be retested after three years. The study is ongoing and the results of the first screening round are reported herein.
Results
Valid results for cytology and HPV testing were obtained for 3,993 women. The overall prevalence of HR-HPV was 12.7%, of HPV-16 2.7% and of HPV-18 1.4%. Of those referred for colposcopy, cervical intraepithelial neoplasia grade 2 or worse (CIN2+) was detected in 41 women (1.07%). At the threshold of CIN2+, cytology [atypical squamous cells of undetermined significance (ASC-US) or worse] and HPV testing showed a sensitivity of 53.7% and 100% respectively, without change between age groups. Cytology and HPV testing showed specificity of 96.8% and 90.3% respectively, which was increased in older women (≥30) in comparison to younger ones (25–29). Genotyping for HPV16/18 had similar accuracy to cytology for the detection of CIN2+ (sensitivity: 58.5%; specificity 97.5%) as well as for triage to colposcopy (sensitivity: 58.5% vs 53.7% for cytology).
Conclusion
HPV testing has much better sensitivity than cytology to identify high-grade cervical lesions with slightly lower specificity. HPV testing with individual HPV-16/HPV-18 genotyping could represent a more accurate methodology for primary cervical cancer screening in comparison to liquid-based cytology, especially in older women.
doi:10.1371/journal.pone.0119755
PMCID: PMC4368762  PMID: 25793281
11.  Human Papillomavirus Infection in Women from Tlaxcala, Mexico 
Brazilian Journal of Microbiology  2010;41(3):749-756.
Cervical cancer is an important health problem in women living in developing countries. Infection with some genotypes of human papillomavirus (HPV) is the most important risk factor associated with cervical cancer. Little information exists about HPV genotype distribution in rural and suburban regions of Mexico. Thus, we determined the prevalence of HPV genotypes in women from Tlaxcala, one of the poorest states in central Mexico, and we evaluated age infection prevalence and risk factors associated with cervical neoplasm. A cross-sectional study was conducted in 236 women seeking gynecological care at the Mexican Institute for Social Security in Tlaxcala, Mexico. Cervical scrapings were diagnosed as normal, low-grade, and high-grade squamous intraepithelial lesions (LGSIL, HGSIL). Parallel samples were used to detect HPV genotypes by PCR assays using type-specific primers for HPV 6, 11, 16, 18, and 31. An epidemiological questionnaire was applied. Prevalence of HPV infection was 31.3%. From the infected samples, prevalence of HPV 16 was 45.9%; HPV 18, 31.1%; HPV 31, 16.2%; HPV 6, 10.8%; HPV 11, 6.7%. With regard to age, the highest HPV prevalence (43.5%) was found in the 18- to 24-year-old group and the lowest (19%) in the 45- to 54-year-old group. None of the risk factors showed association with cervical neoplasia grade. HPV 16 was the most common in cervical lesions. HPV was present in 22% of normal samples and, of these, 82.6% represented high-risk HPVs. Tlaxcala showed HPV prevalence comparable to that of the largest cities in Mexico, with higher prevalence for HPV 31.
doi:10.1590/S1517-83822010000300027
PMCID: PMC3768634  PMID: 24031552
Epidemiology; Human papillomavirus; Mexico; PCR; Squamous intraepithelial lesions
12.  Baseline prevalence and type distribution of human papillomavirus in healthy Chinese women aged 18–25 years enrolled in a clinical trial 
Baseline human papillomavirus (HPV) prevalence and type distribution were evaluated in young Chinese women enrolled in a clinical trial of an HPV vaccine (ClinicalTrials.gov registration NCT00779766). Cervical specimens and blood samples were collected at baseline from women aged 18–25 years (n = 6,051) from four sites across Jiangsu province. Cervical specimens were tested for HPV DNA by SPF10 PCR-DEIA-LiPA25 version 1, and HPV-16/18 type-specific polymerase chain reaction. Anti-HPV-16 and anti-HPV-18 antibody titres were quantified by enzyme-linked immunosorbent assay. At baseline, 15.3% of women were DNA positive for any of 14 HPV high-risk (hr) types (HPV-16/18/31/33/35/39/45/51/52/56/58/59/66/68). The most commonly detected hrHPV types in cervical specimens were HPV-52 (4.0%) and HPV-16 (3.7%). High-risk HPV DNA-positivity increased with severity of cytological abnormalities: 39.3% in atypical squamous cells of undetermined significance, 85.0% in low-grade squamous intraepithelial lesions and 97.8% in high-grade squamous intraepithelial lesions (HSIL). The hrHPV types most frequently detected in HSIL were HPV-16 (63.0%), HPV-18 (17.4%), HPV-52 (17.4%), HPV-58 (15.2%) and HPV-33 (15.2%). The hrHPV types most frequently detected in cervical intraepithelial neoplasia 2+ were HPV-16 (66.1%), HPV-33 (16.1%), HPV-52 (16.1%), HPV-58 (14.5%) and HPV-51 (11.3%). Multiple hrHPV infections were reported for 24.4% of hrHPV DNA positive women. Regardless of baseline HPV DNA status, 30.5% and 16.0% of subjects were initially seropositive for anti-HPV-16 and anti-HPV-18, respectively. In conclusion, the high baseline seropositivity rate and intermediate prevalence of cervical hrHPV types in Chinese women aged 18–25 years underlines the importance of early HPV vaccination in this population.
What's new?
In China, cervical cancer is the second most frequent cancer among women aged 15–44 years. The authors collected baseline data on prevalence and type distribution of human papillomavirus (HPV) from more than 6,000 healthy Chinese women aged 18–25 years participating in a large vaccine efficacy trial. Regardless of cytology, 15.3% of women were positive for high-risk HPV types, with HPV-52 (4.0%), HPV-16 (3.7%), HPV-51 (1.7%) and HPV-58 (1.5%) being the most frequently detected. This high baseline prevalence of high-risk HPV types underscores the importance of early vaccination among Chinese women.
doi:10.1002/ijc.28896
PMCID: PMC4277334  PMID: 24740547
human papillomavirus; China; women; prevalence; type distribution
13.  A Population-Based Evaluation of a Publicly Funded, School-Based HPV Vaccine Program in British Columbia, Canada: Parental Factors Associated with HPV Vaccine Receipt 
PLoS Medicine  2010;7(5):e1000270.
Analysis of a telephone survey by Gina Ogilvie and colleagues identifies the parental factors associated with HPV vaccine uptake in a school-based program in Canada.
Background
Information on factors that influence parental decisions for actual human papillomavirus (HPV) vaccine receipt in publicly funded, school-based HPV vaccine programs for girls is limited. We report on the level of uptake of the first dose of the HPV vaccine, and determine parental factors associated with receipt of the HPV vaccine, in a publicly funded school-based HPV vaccine program in British Columbia, Canada.
Methods and Findings
All parents of girls enrolled in grade 6 during the academic year of September 2008–June 2009 in the province of British Columbia were eligible to participate. Eligible households identified through the provincial public health information system were randomly selected and those who consented completed a validated survey exploring factors associated with HPV vaccine uptake. Bivariate and multivariate analyses were conducted to calculate adjusted odds ratios to identify the factors that were associated with parents' decision to vaccinate their daughter(s) against HPV. 2,025 parents agreed to complete the survey, and 65.1% (95% confidence interval [CI] 63.1–67.1) of parents in the survey reported that their daughters received the first dose of the HPV vaccine. In the same school-based vaccine program, 88.4% (95% CI 87.1–89.7) consented to the hepatitis B vaccine, and 86.5% (95% CI 85.1–87.9) consented to the meningococcal C vaccine. The main reasons for having a daughter receive the HPV vaccine were the effectiveness of the vaccine (47.9%), advice from a physician (8.7%), and concerns about daughter's health (8.4%). The main reasons for not having a daughter receive the HPV vaccine were concerns about HPV vaccine safety (29.2%), preference to wait until the daughter is older (15.6%), and not enough information to make an informed decision (12.6%). In multivariate analysis, overall attitudes to vaccines, the impact of the HPV vaccine on sexual practices, and childhood vaccine history were predictive of parents having a daughter receive the HPV vaccine in a publicly funded school-based HPV vaccine program. By contrast, having a family with two parents, having three or more children, and having more education was associated with a decreased likelihood of having a daughter receive the HPV vaccine.
Conclusions
This study is, to our knowledge, one of the first population-based assessments of factors associated with HPV vaccine uptake in a publicly funded school-based program worldwide. Policy makers need to consider that even with the removal of financial and health care barriers, parents, who are key decision makers in the uptake of this vaccine, are still hesitant to have their daughters receive the HPV vaccine, and strategies to ensure optimal HPV vaccine uptake need to be employed.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
About 10% of cancers in women occur in the cervix, the structure that connects the womb to the vagina. Every year, globally, more than a quarter of a million women die because of cervical cancer, which only occurs after the cervix has been infected with a human papillomavirus (HPV) through sexual intercourse. There are many types of HPV, a virus that infects the skin and the mucosa (the moist membranes that line various parts of the body, including the cervix). Although most people become infected with HPV at some time in their life, most never know they are infected. However, some HPV types cause harmless warts on the skin or around the genital area and several—in particular, HPV 16 and HPV 18, so-called high-risk HPVs—can cause cervical cancer. HPV infections are usually cleared by the immune system, but about 10% of women infected with a high-risk HPV develop a long-term infection that puts them at risk of developing cervical cancer.
Why Was This Study Done?
Screening programs have greatly reduced cervical cancer deaths in developed countries in recent decades by detecting the cancer early when it can be treated; but it would be better to prevent cervical cancer ever developing. Because HPV is necessary for the development of cervical cancer, vaccination of girls against HPV infection before the onset of sexual activity might be one way to do this. Scientists recently developed a vaccine that prevents infection with HPV 16 and HPV 18 (and with two HPVs that cause genital warts) and that should, therefore, reduce the incidence of cervical cancer. Publicly funded HPV vaccination programs are now planned or underway in several countries; but before girls can receive the HPV vaccine, parental consent is usually needed, so it is important to know what influences parental decisions about HPV vaccination. In this study, the researchers undertake a telephone survey to determine the uptake of the HPV vaccine by 11-year-old girls (grade 6) in British Columbia, Canada, and to determine the parental factors associated with vaccine uptake; British Columbia started a voluntary school-based HPV vaccine program in September 2008.
What Did the Researchers Do and Find?
In early 2009, the researchers contacted randomly selected parents of girls enrolled in grade 6 during the 2008–2009 academic year and asked them to complete a telephone survey that explored factors associated with HPV vaccine uptake. 65.1% of the 2,025 parents who completed the survey had consented to their daughter receiving the first dose of HPV vaccine. By contrast, more than 85% of the parents had consented to hepatitis B and meningitis C vaccination of their daughters. Nearly half of the parents surveyed said their main reason for consenting to HPV vaccination was the effectiveness of the vaccine. Conversely, nearly a third of the parents said concern about the vaccine's safety was their main reason for not consenting to vaccination and one in eight said they had been given insufficient information to make an informed decision. In a statistical analysis of the survey data, the researchers found that a positive parental attitude towards vaccination, a parental belief that HPV vaccination had limited impact on sexual practices, and completed childhood vaccination increased the likelihood of a daughter receiving the HPV vaccine. Having a family with two parents or three or more children and having well-educated parents decreased the likelihood of a daughter receiving the vaccine.
What Do These Findings Mean?
These findings provide one of the first population-based assessments of the factors that affect HPV vaccine uptake in a setting where there are no financial or health care barriers to vaccination. By identifying the factors associated with parental reluctance to agree to HPV vaccination for their daughters, these findings should help public-health officials design strategies to ensure optimal HPV vaccine uptake, although further studies are needed to discover why, for example, parents with more education are less likely to agree to vaccination than parents with less education. Importantly, the findings of this study, which are likely to be generalizable to other high-income countries, indicate that there is a continued need to ensure that the public receives credible, clear information about both the benefits and long-term safety of HPV vaccination.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000270.
The US National Cancer Institute provides information about cervical cancer for patients and for health professionals, including information on HPV vaccines (in English and Spanish)
The US Centers for Disease Control and Prevention also has information about cervical cancer and about HPV
The UK National Health Service Choices website has pages on cervical cancer and on HPV vaccination
More information about cervical cancer and HPV vaccination is available from the Macmillan cancer charity
ImmunizeBC provides general information about vaccination and information about HPV vaccination in British Columbia
MedlinePlus provides links to additional resources about cervical cancer (in English and Spanish)
doi:10.1371/journal.pmed.1000270
PMCID: PMC2864299  PMID: 20454567
14.  Epidemiology of HPV genotypes in Uganda and the role of the current preventive vaccines: A systematic review 
Background
Limited data are available on the distribution of human papillomavirus (HPV) genotypes in the general population and in invasive cervical cancer (ICC) in Uganda. Yet, with the advent of preventive HPV vaccines that target HPV 16 and 18 responsible for causing about 70% of ICC cases in the world, such information is crucial to predict how vaccination and HPV-based screening will influence prevention of ICC.
Methods
To review the distribution of HPV infection and prevalent genotypes, electronic databases (e.g. PubMed/MEDLINE and HINARI) were searched for peer reviewed English articles on HPV infection up to November 30, 2010. Eligible studies were selected according to the following criteria: DNA-confirmed cervical or male genital HPV prevalence and genotypes, HPV incidence estimates and HPV seroprevalence among participants.
Results
Twenty studies were included in the review. Among HIV negative adult women, the prevalence of HR-HPV infections ranged from 10.2% -40.0% compared to 37.0% -100.0% among HIV positive women. Among HIV positive young women aged below 25 years, the prevalence of HR-HPV genotypes ranged from 41.6% -75.0% compared to 23.7% -67.1% among HIV negative women. Multiple infections with non vaccine HR-HPV genotypes were frequent in both HIV positive and HIV negative women. The main risk factors for prevalent HPV infections were age, lifetime number of sexual partners and HIV infection. Incident infections with HR-HPV genotypes were more frequent among adult HIV positive than HIV negative women estimated at 17.3 and 7.0 per 100 person-years, respectively. Similarly, incident HR-HPV among young women aged below 25 years were more frequent among HIV positive (40.0 per 100 person-years) than HIV negative women (20.3 per 100 person-years) women. The main risk factor for incident infection was HIV infection. HPV 16 and 18 were the most common genotypes in ICC with HPV 16/18 contributing up to 73.5% of cases with single infections.
Among uncircumcised adult HIV positive males, HR-HPV prevalence ranged from 55.3% -76.6% compared to 38.6% -47.6% in HIV negative males. Incident and multiple HR-HPV infections were frequent in HIV positive males. Being uncircumcised was the main risk factor for both prevalent and incident HPV infection.
Conclusion
Infections with HR-HPV genotypes were very common particularly among HIV positive individuals and young women irrespective of HIV status. Given the high prevalence of HIV infection, HPV-associated conditions represent a major public health burden in Uganda. However, although the most common HPV genotypes in ICC cases in Uganda were those targeted by current preventive vaccines, there were a large number of individuals infected with other HR-HPV genotypes. Technology allowing, these other HR-HPV types should be considered in the development of the next generation of vaccines.
doi:10.1186/1750-9378-6-11
PMCID: PMC3163594  PMID: 21749691
15.  HPV prevalence and genotype distribution in a population-based split-sample study of well-screened women using CLART HPV2 Human Papillomavirus genotype microarray system 
BMC Infectious Diseases  2014;14:413.
Background
Human papillomavirus (HPV) genotyping assays are becoming increasingly attractive for use in mass screening, as they offer a possibility to integrate HPV screening with HPV vaccine monitoring, thereby generating a synergy between the two main modes of cervical cancer prevention. The Genomica CLART HPV2 assay is a semi-automated PCR-based microarray assay detecting 35 high-risk and low-risk HPV genotypes. However, few reports have described this assay in cervical screening.
An aim of the present study, Horizon, was to assess the prevalence of high-risk HPV infections in Copenhagen, Denmark, an area with a high background risk of cervical cancer where women aged 23-65 years are targeted for organized screening.
Methods
Material from 5,068 SurePath samples of women participating in routine screening and clinical follow-up of cervical abnormalities was tested using liquid based cytology, CLART HPV2 and Hybrid Capture 2 (HC2).
Results
At least one of the 35 defined genotypes was detected by CLART in 1,896 (37%) samples. The most frequent high-risk genotypes were HPV 16 (7%), HPV 52 (5%), and HPV 31 (4%). The most frequent low-risk genotypes were HPV 53 (5%), HPV 61 (4%), and HPV 66 (3%). Among 4,793 women targeted by the screening program (23-65 years), 1,166 (24%) tested positive for one or more of the 13 high-risk genotypes. This proportion decreased from 40% at age 23-29 years to 10% at age 60-65 years. On HC2, 1,035 (20%) samples were positive for any high-risk and thus CLART showed a higher analytical sensitivity for 13 high-risk HPV genotypes than HC2, and this was found in all age-groups and in women normal cytology.
Conclusions
CLART performed well with a positive reproducibility for high-risk genotypes of 86%, and a negative reproducibility of 97%. This report furthermore updates the genotype distribution in Denmark prior to the inclusion of the HPV-vaccinated cohorts into the screening program, and as such represents a valuable baseline for future vaccine impact assessment.
doi:10.1186/1471-2334-14-413
PMCID: PMC4122758  PMID: 25064473
Human papillomavirus; Cervical cancer; Genotyping; Screening; Assay; CLART; HC2; Vaccine monitoring
16.  HPV genotypes and associated cervical cytological abnormalities in women from the Pearl River Delta region of Guangdong province, China: a cross-sectional study 
BMC Infectious Diseases  2014;14:388.
Background
It is important to understand the specific HPV genotype distribution in screen-detected lesions. HPV Genotype is helpful for separating HPV-positive women at greater risk of cancer from those who can regress spontaneously and for preventing cervical cancer at early stage. The aim of this study was to investigate the high-risk HPV genotype distribution among cervical cytology abnormality in Pearl River Delta Region, Southern China
Methods
5585 HPV-infected women were screened from 77069 women in Pearl River Delta Region. Information was obtained from 3226 screened subjects through questionnaires and personal interviews. Exfoliated cervical cells were collected by doctors for HPV test with MassARRAY (Sequenom, Sandiego, CA) technique based on the matrix-assisted laser desorption/ionization time-of flight (MALDI-TOF) mass spectrometry (MS). The ThinPrep cytology test was performed to screen for cervical cancer. Unconditional logistic was used to determine the most common HPV carcinogenic types.
Results
Of the 3226 HPV-positive samples tested, 1744 (54.1%) with normal cervical cytology, 1482 (45.9%) with abnormal cytology. The five most common HPV types in this study were HPV16 (20.2%), HPV52 (17.1%), HPV58 (13.2%), HPV18 (9.5%), HPV6 (7.6%). Overall, HPV16 (OR = 10.5, 95% CI: 3.7 ~ 29.6), HPV33 (OR = 9.1, 95% CI: 2.8 ~ 29.2), HPV58 (OR = 6.3, 95% CI: 2.1 ~ 18.6), HPV31 (OR = 4.5, 95% CI: 1.3 ~ 15.5), multiple genotype infection (OR = 3.0, 95% CI: 1.7 ~ 14.7), especially HPV16 and HPV33, increased the risk of cytology abnormalities.
Conclusions
HPV16, HPV31, HPV33, HPV58, and multiple HPV genotype infection increased the risk of cytology abnormalities in Pearl River Delta Region and might be useful for the screening, preventing, treating, and monitoring of pre-cancer lesions in southern China.
doi:10.1186/1471-2334-14-388
PMCID: PMC4226991  PMID: 25016305
Human papillomavirus; Cytology; Cross-sectional study; Infection
17.  A cross-sectional study to estimate high-risk human papillomavirus prevalence and type distribution in Italian women aged 18–26 years 
Background
Pre-vaccination information on HPV type-specific prevalence in target populations is essential for designing and monitoring immunization strategies for cervical cancer (CC) prevention. Data on HPV prevalence in Italy are available for women over the age of 24 years, target of the population-based CC screening programmes; while data of HPV prevalence in younger ages are very limited. The present study enrolled Italian women aged 18–26 years in order to assess the prevalence and distribution of high-risk (HR) HPV types. Risk-factors correlated with HR-HPV positivity were also described.
Methods
A sample of 2,289 women was randomly selected from the resident population lists of ten Local Health Units (LHUs) located in six Italian Regions scattered across the country; both rural and urban LHUs were involved. Women aged between 18 and 26 years and living in the selected LHUs were included in the study; pregnant women and women who did not speak Italian were excluded. A total of 1,102 women met the inclusion criteria and agreed to participate. Participants were offered pap test and Hybrid-Capture 2 (HC2) test for HR-HPV types and genotyping was performed on positive smears.
Results
Out of 1,094 valid samples, 205 (18.7%) were HR-HPV positive. Women with 2–4 (ORadj = 4.15, 95%CI: 2.56-6.72) and ≥5 lifetime partners (ORadj = 10.63, 95%CI: 6.16-18.36) and women who have used any contraceptive in the last six months (ORadj = 1.67, 95%CI: 1.09-2.54) had a higher risk to be infected; women living with their partner had a lower risk (ORadj = 0.56, 95%CI: 0.34-0.92) to acquire infection than women living with parents/friends/alone. Among HC2 positive women, HPV16 was the most prevalent type (30.9%), followed by 31 (19.6%), 66 (12.9%), 51 (11.3%), 18 (8.8%), 56 (8.8%). Co-infections of HR-HC2 targeted types were found in 20.4% of positive samples. The HR-HPV prevalence in women with abnormal cytology (52.4%) was significantly higher than in women with normal cytology (14.6%); however 33.0% of HR-HPV infected women had an abnormal cytology.
Conclusion
HR-HPV prevalence in Italian women aged 18–26 years was 19%, higher than what detected for older women, by other studies using the same molecular method and laboratory network; this result supports the choice of electing girls before the sexual debut as the primary target of HPV vaccination. The HPV type distribution found in this study may represent a baseline picture; an accurate post-vaccine surveillance is necessary to early detect a possible genotype replacement. The high prevalence of viral types other than vaccine-HPV types supports the necessity to guarantee the progression of CC screening programmes in vaccinated women.
doi:10.1186/1471-2334-13-74
PMCID: PMC3599585  PMID: 23390953
Human papillomavirus; High-risk types; Prevalence; Genotype distribution; Cervical cancer; Italy; Risk factors
18.  HPV16/18 genotyping for the triage of HPV positive women in primary cervical cancer screening in Chile 
Background
We previously conducted a population-based screening trial of high-risk human papillomavirus (hrHPV) testing and conventional cytology, demonstrating higher sensitivity (92.7 % vs 22.1 % for CIN2+) but lower positive predictive value (10.5 % vs 23.9 %) of hrHPV testing. Here we report the performance of HPV16/18 genotyping to triage the hrHPV positive participants.
Methods
Women aged 25 years and older received hrHPV (Hybrid Capture 2) and Papanicolaou testing; positives by either test underwent colposcopy and directed biopsy, as did a sample of double-negatives. hrHPV positive women were reflex-tested with HPV16/18 genotyping (Digene HPV Genotyping PS Test).
Results
Among the 8,265 participants, 10.7 % were hrHPV positive, 1.7 % had ASCUS+ cytology, 1.2 % had CIN2+; 776 (88 %) hrHPV positive women had complete results, of whom 38.8 % were positive for HPV16 (24.0 %), HPV18 (9.7 %) or both (5.1 %). CIN2+ prevalence in HPV16/18 positive women (16.3 %, 95 % CI 12.3-20.9) was twice that of HPV16/18 negative women (8.0 %, 95 % CI 5.7-10.8). HPV16/18 genotyping identified 40.5 % of CIN2, 66.7 % of CIN3 and 75.0 % of cancers. Compared to hrHPV screening alone, HPV16/18 triage significantly reduced the referral rate (10.7 % vs 3.7 %) and the number of colposcopies required to detect one CIN2+ (9 vs 6). When HPV16/18 negative women with baseline ASCUS+ cytology were also colposcopied, an additional 14 % of CIN2+ was identified; referral increased slightly to 4.2 %.
Conclusions
HPV16/18 triage effectively stratified hrHPV positive women by their risk of high-grade lesions. HPV16/18 positive women must be referred immediately; referral could be deferred in HPV16/18 negative women given the slower progression of non-HPV16/18 lesions, however, they will require active follow-up.
doi:10.1186/s13027-015-0038-5
PMCID: PMC4656177  PMID: 26600869
Cervical cancer screening; Human papillomavirus; HPV DNA testing; HPV 16; HPV 18; Genotype; Triage
19.  High prevalence of human papillomavirus infection in American Indian women of the Northern Plains 
Gynecologic oncology  2007;107(2):236-241.
Objectives
Cervical cancer is the leading gynecological malignancy worldwide, and the incidence of this disease is very high in American Indian women. Infection with the Human Papillomavirus (HPV) is responsible for more than 95% of cervical squamous carcinomas. Therefore, the main objective of this study was to analyze oncogenic HPV infections in American Indian women residing in the Northern Plains.
Methods
Cervical samples were collected from 287 women attending a Northern Plains American Indian reservation outpatient clinic. DNA was extracted from the cervical samples and HPV specific DNA were amplified by polymerase chain reaction (PCR) using the L1 consensus primer sets. The PCR products were hybridized with the Roche HPV Line Blot assay for HPV genotyping to detect 27 different low and high-risk HPV genotypes. The chi-square test was performed for statistical analysis of the HPV infection and cytology diagnosis data.
Results
Of the total 287 patients, 61 women (21.25%) tested positive for HPV infection. Among all HPV-positive women, 41 (67.2%) were infected with high-risk HPV types. Of the HPV infected women, 41% presented with multiple HPV genotypes. Additionally, of the women infected with oncogenic HPV types, 20 (48.7%) were infected with HPV 16 and 18 and the remaining 21 (51.3%) were infected with other oncogenic types (i.e., HPV59, 39, 73). Women infected with oncogenic HPV types had significantly higher (p=0.001) abnormal Papanicolaou smear tests (Pap test) compared to women who were either HPV negative or positive for non-oncogenic HPV types. The incidence of HPV infection was inversely correlated (p<0.05) with the age of the patients, but there was no correlation (p=0.33) with seasonal variation.
Conclusions
In this study, we observed a high prevalence of HPV infection in American Indian women residing on Northern Plains Reservations. In addition, a significant proportion of the oncogenic HPV infections were other than HPV16 and 18.
doi:10.1016/j.ygyno.2007.06.007
PMCID: PMC2396448  PMID: 17659767
Human Papillomavirus; American Indian; Northern Plains; Cervical cancer; Cervical cancer diagnosis
20.  Sex-Specific Immunization for Sexually Transmitted Infections Such as Human Papillomavirus: Insights from Mathematical Models 
PLoS Medicine  2011;8(12):e1001147.
Johannes Bogaards and colleagues use mathematical models to investigate whether vaccinating females only, males only, or both sexes is the best way to achieve the most effective reduction in the population prevalence of sexually-transmitted infections
Background
Sex-specific differences regarding the transmissibility and the course of infection are the rule rather than the exception in the epidemiology of sexually transmitted infections (STIs). Human papillomavirus (HPV) provides an example: disease outcomes differ between men and women, as does the potential for transmission to the opposite sex. HPV vaccination of preadolescent girls was recently introduced in many countries, and inclusion of boys in the vaccination programs is being discussed. Here, we address the question of whether vaccinating females only, males only, or both sexes is the most effective strategy to reduce the population prevalence of an STI like HPV.
Methods and Findings
We use a range of two-sex transmission models with varying detail to identify general criteria for allocating a prophylactic vaccine between both sexes. The most effective reduction in the population prevalence of infection is always achieved by single-sex vaccination; vaccinating the sex with the highest prevaccine prevalence is the preferred strategy in most circumstances. Exceptions arise only when the higher prevaccine prevalence is due to a substantially lower rate of natural immunity, or when natural immunity is lifelong, and a prolonged duration of infectiousness coincides with increased transmissibility. Predictions from simple models were confirmed in simulations based on an elaborate HPV transmission model. Our analysis suggests that relatively inefficient genital transmission from males to females might render male vaccination more effective in reducing overall infection levels. However, most existing HPV vaccination programs have achieved sufficient coverage to continue with female-only vaccination.
Conclusions
Increasing vaccine uptake among preadolescent girls is more effective in reducing HPV infection than including boys in existing vaccination programs. As a rule, directing prophylactic immunization at the sex with the highest prevaccine prevalence results in the largest reduction of the population prevalence.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
About 10% of cancers in women occur in the cervix, the structure that connects the womb to the vagina. Every year, more than a quarter of a million women (85% of them in developing countries) die because of cervical cancer, which only occurs after the cervix has been infected with a human papillomavirus (HPV) through sexual intercourse (HPV is one of more than thirty sexually transmissable organisms that, globally, cause many millions of sexually transmitted infections every year). There are many types of HPV, a virus that infects the skin and the mucosa (the moist membranes that line various parts of the body, including the cervix). Most people become infected with HPV at some time during their life, but most never know they have been infected. Some HPV types cause harmless warts on the skin or around the genital area, and several—in particular HPV16 and HPV18, so-called high-risk HPVs—can cause cervical cancer (and some other cancers, including anal, penile, head, and neck cancers). HPV infections are usually cleared by the immune system, but about 10% of women infected with a high-risk HPV develop a long-term infection that puts them at risk of developing cervical cancer.
Why Was This Study Done?
Screening programs have greatly reduced cervical cancer deaths in developed countries by detecting the cancer early, when it can be treated. However, it would be better to prevent cervical cancer ever developing. Moreover, most women in developing countries do not have access to screening. Because infection with specific HPV types can cause the development of some types of cervical cancer, vaccination of girls against HPV before the onset of sexual activity might be one way to prevent cervical cancer. Scientists recently developed a vaccine that prevents infection with HPV16 and HPV18, and HPV vaccination programs have been introduced in several countries. These programs are currently directed only at girls because HPV-related illness and death are higher among women than men, but should boys also be included in HPV vaccination programs? Men would benefit directly from immunization against HPV-related diseases, but, in addition, vaccination of boys might help to reduce the circulation of HPV in the population, thereby indirectly improving the protection of women through so-called “herd immunity.” In this study, the researchers used mathematical models to investigate whether vaccinating girls only, boys only, or both sexes is the most effective way to reduce the population prevalence of HPV infection (the proportion of the population infected with HPV).
What Did the Researchers Do and Find?
The researchers first used a range of standard two-sex mathematical models of infection and transmission in heterosexual populations to identify general criteria for allocating an HPV vaccine between the sexes. They found that the most effective reduction in the population prevalence of HPV infection was always achieved by single-sex vaccination and that, in most situations, the preferred strategy was to vaccinate the sex with the highest prevaccine prevalence of HPV infection. The researchers confirmed these predictions using a more elaborate HPV transmission model that incorporated differences among individuals in age and level of sexual activity. Importantly, this second analysis also suggested that for existing girl-only vaccination programs, increasing coverage of vaccination among girls would bolster herd immunity more effectively than switching to a policy of vaccinating both sexes.
What Do These Findings Mean?
The findings of this study suggest that increasing vaccine uptake among preadolescent girls is a more effective way to reduce HPV infection than including boys in existing vaccination programs. They also suggest that directing HPV vaccination at the sex with the highest prevaccine prevalence of infection will reduce the population prevalence of HPV most effectively. Although the accuracy of these findings is dependent on the assumptions included in the mathematical transmission models used by the researchers, these findings support a policy of increasing female HPV vaccine coverage as far as possible, within the limits set by vaccine acceptance and economic constraints. More generally, these findings suggest that single-sex preventative interventions might be the best way to reduce heterosexual transmission of other sexually transmitted infections and that targeting the sex with the highest prevalence of infection might achieve the most effective reduction in the population prevalence of these common diseases.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001147.
The US National Cancer Institute provides information about cervical cancer for patients and for health professionals, including information on HPV vaccines (in English and Spanish)
The US Centers for Disease Control and Prevention also has information about cervical cancer and HPV
The UK National Health Service Choices website has pages on cervical cancer and HPV vaccination (available in several languages and including a short video of girls talking about HPV vaccination)
The PREHDICT project investigates health-economic modeling of prevention strategies for HPV-related diseases in European countries; information about this project is available from the European Cervical Cancer Association
More information about cervical cancer and HPV vaccination is available from Macmillan Cancer Support
Personal stories about cervical cancer are available through the charity Healthtalkonline
MedlinePlus provides links to additional resources about cervical cancer and other sexually transmitted infections (in English and Spanish)
doi:10.1371/journal.pmed.1001147
PMCID: PMC3243713  PMID: 22205887
21.  Human papillomavirus detection in women with and without human immunodeficiency virus infection in Colombia 
BMC Cancer  2014;14:451.
Background
HIV infection leads to a decreasing immune response, thereby facilitating the appearance of other infections, one of the most important ones being HPV. However, studies are needed for determining associations between immunodeficiency caused by HIV and/or the presence of HPV during the course of cervical lesions and their degree of malignancy. This study describes the cytological findings revealed by the Papanicolaou test, laboratory characteristics and HPV molecular profile in women with and without HIV infection.
Methods
A total of 216 HIV-positive and 1,159 HIV-negative women were invited to participate in the study; PCR was used for the molecular detection of HPV in cervical samples. Statistical analysis (such as percentages, Chi-square test and Fisher’s exact test when applicable) determined human papillomavirus (HPV) infection frequency (single and multiple) and the distribution of six types of high-risk-HPV in women with and without HIV infection. Likewise, a logistic regression model was run to evaluate the relationship between HIV-HPV infection and different risk factors.
Results
An association was found between the frequency of HPV infection and infection involving 2 or more HPV types (also known as multiple HPV infection) in HIV-positive women (69.0% and 54.2%, respectively); such frequency was greater than that found in HIV-negative women (44.3% and 22.7%, respectively). Statistically significant differences were observed between both groups (p = 0.001) regarding HPV presence (both in infection and multiple HPV infection). HPV-16 was the most prevalent type in the population being studied (p = 0.001); other viral types had variable distribution in both groups (HIV-positive and HIV-negative). HPV detection was associated with <500 cell/mm3 CD4-count (p = 0.004) and higher HIV-viral-load (p = 0.001). HPV-DNA detection, <200 cell/mm3 CD4-count (p = 0.001), and higher HIV-viral-load (p = 0.001) were associated with abnormal cytological findings.
Conclusions
The HIV-1 positive population in this study had high multiple HPV infection prevalence. The results for this population group also suggested a greater association between HPV-DNA presence and cytological findings. HPV detection, together with low CD4 count, could represent useful tools for identifying HIV-positive women at risk of developing cervical lesions.
doi:10.1186/1471-2407-14-451
PMCID: PMC4067500  PMID: 24942545
Human papillomavirus; Human immunodeficiency virus; Multiple infection; Papanicolaou test; Epidemiology
22.  Prevalence of human papillomavirus in young Italian women with normal cytology: how should we adapt the national vaccination policy? 
BMC Infectious Diseases  2013;13:575.
Background
Human Papillomavirus (HPV) is the most common sexually transmitted infection. In Italy, HPV vaccination is now offered free of charge to 12-year-old females. However, some regional health authorities have extended free vaccination to other age-groups, especially to girls under 18 years of age. We conducted a multicentre epidemiological study to ascertain the prevalence of different genotypes of HPV in young Italian women with normal cytology, with the aim of evaluating the possibility of extending vaccination to older females.
Methods
The study was performed in 2010. Women aged 16–26 years with normal cytology were studied. Cervical samples were analyzed to identify the presence of HPV by PCR amplification of a segment of ORF L1 (450 bp). All positive HPV-DNA samples underwent viral genotype analysis by means of a restriction fragment length polymorphism assay.
Results
Positivity for at least one HPV genotype was found in 18.2% of the 566 women recruited: 48.1% in the 16–17 age-class, 15.4 in the 18–20 age-class, 21.9% in the 21–23 age-class, and 15.5% in the 24–26 age-class; 10.1% of women were infected by at least one high-risk HPV genotype. HPV-16 was the most prevalent genotype. Only 4 (0.7%), 4 (0.7%) and 3 (0.5%) women were infected by HPV-18, HPV-6 and HPV-11, respectively. Of the HPV-DNA-positive women, 64.1% presented only one viral genotype, while 24.3% had multiple infections. The HPV genotypes most often involved in multiple infections were high-risk. A high prevalence was noted in the first years of sexual activity (48.1% of HPV-DNA-positive women aged 16–17 years); HPV prevalence subsequently declined and stabilized.
The estimate of cumulative proportions of young women free from any HPV infection at each age was evaluated; 93.3% and 97.1% of 26 year-old women proved free from HPV-16 and/or HPV-18 and from HPV-6 and/or HPV-11, respectively.
Conclusions
Our findings confirm the crucial importance of conducting studies on women without cytological damage, in order to optimise and up-date preventive interventions against HPV infection, and suggest that vaccinating 26-year-old females at the time of their first pap-test is to be recommend, though this issue should be further explored.
doi:10.1186/1471-2334-13-575
PMCID: PMC4029487  PMID: 24313984
Papillomavirus; HPV; Cervical cancer prevention; Vaccination; HPV epidemiology; Young women
23.  Multiple high risk HPV infections are common in cervical neoplasia and young women in a cervical screening population 
Journal of Clinical Pathology  2004;57(1):68-72.
Aims: If human papillomavirus (HPV) testing is to be included within cervical screening programmes, the importance of multiple HPV infections in cervical neoplasia needs to be determined. This study investigated the diversity of multiple HPV types in a routine cervical screening population, and assessed associations with cervical neoplasia.
Methods: Overall HPV prevalence, type specific prevalence, and extent of multiple infection were assessed in residual material from 3444 liquid based cytology samples, using real time GP5+/GP6+ polymerase chain reaction for screening and linear array assay for genotyping. HPV status was studied in relation to age and concurrent cytological evidence of dyskaryosis.
Results: Twenty per cent of samples were HPV positive. HPV type diversity was broad, and multiple HPV infections occurred in half of the HPV positive samples. Younger women were significantly more likely to harbour multiple high risk HPV (HR-HPV) infections. Infections with multiple HR-HPV types were found in 3.4% of samples negative for neoplasia and in 33.3%, 41.8%, and 40.4% of samples with borderline, mild, or high grade dyskaryosis, respectively. Single HR-HPV infections were found in 4.9%, 38.6%, 45.0%, and 51.1% of negative, borderline, mild, or high grade dyskaryosis samples, respectively.
Conclusions: Multiple HR-HPV infections were most prevalent in young women. Multiple HR-HPV infections were not more frequent in high grade than in low grade cervical neoplasia, reflecting common sexual transmission of multiple HR-HPV. Prospective cohort studies linking sequential loss or gain of HPV types with cytological analysis are required to assess the impact of multiple HR-HPV infections on neoplastic progression.
PMCID: PMC1770158  PMID: 14693839
human papillomavirus; multiple infection; cervical neoplasia
24.  Prevalence of cervical infection with HPV type 16 and 18 in Vietnam: implications for vaccine campaign 
BMC Cancer  2013;13:53.
Background
The Expanded Program on Immunization currently considers offering Human Papilomavirus vaccine on a routine basis in Vietnam. However, as the current available vaccine can prevent only two types HPV 16 and 18, before implementing a large-scale vaccine campaign we need information about the prevalence of infection with only HPV 16 and 18 in Viet Nam. This study was done in 5 large cities in Vietnam to estimate the prevalence of HPV 16 and/or 18 infections and to explore the distribution of other high risk types of HPV among married women in these provinces.
Methods
The study employed a cross-sectional design with multistage sampling. The sample size included 4500 married women in two rounds (aged ranged from 18-69 years old, median age: 40 year old). Participant were randomly selected, interviewed and given gynaecological examinations. HPV infection status (by real-time PCR kit using TaqMan probe) and HPV genotyping test (by Reverse dot blot) were done for all participants.
Results
The prevalence of cervical infection with HPV type 16 and/or 18 among married women in this study ranged from 3.1% to 7.4%. Many positive HPV cases (ranged from 24.5% to 56.8%) were infected with other type of high risk HPV which can lead to cervical cancer and cannot prevented by currently available vaccines. In addition to HPV 16 and/or 18, most common types of high risk HPV were types 58, 52, 35 and 45. Awareness about HPV and HPV vaccines was still low in the study samples.
Discussion
While it is relevant to implement an HPV vaccine campaign in Viet Nam, it is important to note that one can be infected with multiple types of HPV. Vaccination does not protected against all type of high risk HPV types. Future vaccine campaigns should openly disclose this information to women receiving vaccines.
Conclusion
High prevalence of infection with HPV high risk types was observed in this study. As HPV infection has a high correlation with cervical cancer, this study emphasizes the need for both primary prevention of cervical cancer with HPV vaccines as well as secondary prevention with screening.
doi:10.1186/1471-2407-13-53
PMCID: PMC3583820  PMID: 23374877
Cervical cancer; Human papilloma virus; Vietnam; HPV 16; HPV 18; HPV vaccine
25.  Human papillomavirus (HPV) prevalence and types among Turkish women at a gynecology outpatient unit 
Background
Human Papillomavirus (HPV) is a well-known pathogen for lower genital tract neoplasias, yet little is known regarding HPV prevalence in Turkey. The aim of this study was to investigate the prevalence of HPV DNA and to determine HPV types distribution among women with normal and abnormal cytology.
Methods
A total of five hundred seven (n = 507) women were retrospectively evaluated between 2004-2008. Conventional polymerase chain reaction was used to detect the presence of HPV types in cervicovaginal samples obtained from patients during gynecologic examination.
Results
One hundred four (n = 104) of the women were excluded from the study because of the incomplete data and a total of 403 women were used for the final analysis. There were, 93 (23%) women with cytologic abnormality and 310 (77%) women with normal cytology. Overall, 23% of the women was HPV positive. The overall prevalence of HPV in women with abnormal Pap smears was 36% (93/403), of which in ASCUS 22%, LSIL 51% and HSIL 60%. Also, HPV DNA was positive in 20% of the women with normal cervical cytology. The most common HPV types in cytologically normal women were as follows; HPV 16 (36%), HPV 6 (22%) and HPV 18 (13%). The rate of other HPV types were as follows; HPV11 4.4%, HPV45 4.4%, HPV90 4.4%, HPV35 2.2%, HPV67 2.2%, HPV81 2.2%, and multiple type HPVs 8.9%. The most common HPV types in cytologically abnormal women were HPV 16 (35%), HPV6 (19%) and HPV18 (8%). The rate of multiple HPV infections in women with normal Pap test was 2.2%.
Conclusion
HPV prevalence and type distribution in this study were similar to that reported worldwide at least in our study population. Hovewer, HPV prevalence was more common compared with previous studies reported from Turkey. This might be related with methodology and hospital based patient accrual and high rate of women with abnormal cytology. Further population based prospective studies are needed to eliminate the drawbacks of our study and to determine nonhospital based HPV prevalence in Turkish women.
doi:10.1186/1471-2334-9-191
PMCID: PMC2789077  PMID: 19948015

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