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Global review of age-specific prevalence of HPV in men.

HPV is the most common sexually transmitted infection worldwide, with 6.2 million new infections each year. Early diagnosis and treatment of patients with high-risk HPV infection is important as the virus has been linked to oral, cervical, penile, and anal cancers, as well as being a risk factor for HIV infection. The studies below provide new data on prevalence in different population groups and evidence on health outcomes as a result of HPV vaccination.

A systematic review of the available data published since 1989 on genital HPV-DNA prevalence in men and associated HPV prevalence curves by age for populations throughout the world was published in 2011.64 of the identified 6,600 abstracts reported age-specific HPV prevalence and were included in the review. 38 of these were from populations at high risk of HPV infection, such as STI clinic attenders, HIV-positive men, and partners of women with HPV infection. Studies were from Europe (38%), North America (25%), Central and South America (19%), Asia (11%), and Africa (5%) and included HPV prevalence data from more than 14,800 men in 23 countries. They were generally limited to men >18 years old. HPV prevalence was high among sexually active men in all regions but with considerable variation depending on age, country and region, ranging from 1% to 84% among low-risk men and from 2% to 93% among high-risk men.

Peak HPV prevalence spanned a wide range of ages and, compared with that in women, seems to peak at slightly older ages and remains constant or slightly decreases with increasing age, suggesting longer-term persistence of high-risk HPV infection in men or a higher rate of re-infection. Age-stratified data on HPV 16 and 18, which are associated with cancers, show similar age-related trends across major regions, with few data on young men; HPV 18 was less prevalent than HPV 16. The authors believe that, given the high prevalence of HPV in both low-and high-risk men in many areas, universal HPV vaccination of males in early adolescence is warranted. (1)

A review of the distribution of HPV in the general population and in invasive cervical cancer in Uganda was undertaken to predict how vaccination and HPV-based screening will influence prevention of cancer. Twenty studies were reviewed on high-risk HPV infection using the following criteria: DNA-confirmed cervical or male genital HPV prevalence and genotypes, HPV incidence estimates and HPV seroprevalence among participants. The review found that the prevalence of HPV infection among HIV-positive adult and young women was higher than among HW-negative women. Multiple infections with non-vaccine HPV genotypes were frequent in both HIV-positive and HW-negative women. The main risk factors for prevalent HPV infections were age, lifetime number of sex partners and HW infection. Incident infections with high-risk HPV genotypes were more frequent among adult HIV-positive than HIV-negative women. Similarly, incident high-risk HPV among young women aged <25 years were more frequent among HIV-positive than HIV-negative women. The main risk factor for incident infection was HIV infection. HPV 16 and 18 were the most common genotypes in invasive cervical cancer, with HPV 16 and 18 contributing up to 73.5% of cases with single infections. Among uncircumcised adult HIV-positive men, high-risk HPV prevalence was higher than in HIV-negative men. Incident and multiple high-risk HPV infections were frequent in HIV-positive men. Being uncircumcised was the main risk factor for both prevalent and incident HPV infection. The findings show that infections with high-risk HPV genotypes were very common particularly among HIV-positive adults and young women irrespective of HIV status. Given the high prevalence of HPV infection, HPV-associated conditions represent a major public health burden in Uganda. Although the most common HPV genotypes in invasive cervical cancer cases in Uganda were those targeted by current preventive vaccines, there were a large number of individuals infected with other high-risk HPV genotypes. Technology allowing, these other HPV types should be considered in the development of the next generation of vaccines. (2)

A study of type-specific HPV prevalence in Czech women and men with anogenital diseases analysed 157 squamous cell carcinoma samples, 695 precancerous lesion samples and 64 cervical, vulvar and anal condylomata acuminate samples. 30 different HPV genotypes were detected, HPV 16 being the most prevalent type both in pre-cancerous lesions (45%) and squamous cell carcinomas (59%). In benign lesions, HPV 6 (72%) was the most common type. 61% of carcinoma samples and 43% of pre-cancerous lesion samples contained HPV 16 and/or 18. The presence of HPV types related to the vaccinal ones (HPV 31, 45, 33, 52, 58) were detected in 16% of carcinoma samples and 18% of pre-cancerous lesion samples. HPV 16 and/or 18 were present in 76% of cervical cancer samples. HPV types 6 and/or 11 were detected in 84% of condylomata acuminate samples. The study demonstrates that the prevalence of vaccinal and related HPV types in patients with HPV-associated diseases in the Czech Republic is very high and that implementation of routine vaccination against HPV would greatly reduce the burden of HPV-associated diseases there. (3)

A US-based literature review of diagnosis and basic management of genital, oral, and anal HPV infection found that HPV infection incidence drops in women older than 30 years but remains high for men who have sex with men (MSM) in all age ranges. Currently, even though the incidence of anal cancer among MSM is higher than the incidence of cervical cancer among women, few MSM are identified as high-risk patients in primary care or have received vaccination for human papillomavirus (HPV). The study recommends that doctors should routinely assess the sexual practices of all male patients, especially MSM, and educate them on the HPV infection risks, diagnosis and treatment options. This would have a significant impact in the primary prevention of HPV by routinely offering HPV vaccination to male patients younger than 26 years. (4)

Recent studies provide further evidence on the positive benefits of HPV vaccination. A multi-country randomised, placebo-controlled, double-blind trial of a quadrivalent vaccine (active against HPV types 6, 11, 16, and 18) assessed efficacy in preventing the development of external genital lesions and anogenital HPV infection in boys and men. 4,065 healthy males aged 16-26 years were enrolled and subjects were randomised 1:1 to receive HPV vaccine or placebo at day 1, month 2, and month 6. The study found that quadrivalent HPV vaccine prevented infection with HPV 6, 11, 16, and 18 and the development of related external genital lesions in young men aged 16-26 years. The HPV vaccine was generally well tolerated and safe. (5,6)

An analysis of available studies on whether there is an association between male circumcision and HPV infection stratifies the evidence, based on methods of sampling and detection of HPV infection, HPV type, and the stage of infection, found that there is no consistent association of HPV acquisition with circumcision stares and that circumcision is not protective against non-oncogenic types of HPV. However, circumcision is associated with a reduced prevalence and persistence of oncogenic HPV infections and circumcised men are also less susceptible to multiple infections. These findings indicate that circumcision modulates HPV persistence rather than acquisition. The importance of male circumcision is in promoting HPV infection clearance and is therefore an important adjunct to education, condom use, and vaccination. (7)

Australia implemented a national HPV vaccination programme in 2007, with routine vaccination of 12-13 year old girls and catch-up in young women aged 13-26 years to 2009. The aim of this study was to estimate the impact of the current female-only national vaccination programme on men, and estimate the incremental benefits to men of being included in the programme. The study used preliminary data to estimate vaccination coverage in females. It fitted a dynamic model of sexual behaviour and HPV transmission in Australia to local data on female pre-vaccination age-specific HPV prevalence, predicted the corresponding pre-vaccination prevalence in males due to heterosexual transmission, and modelled the short- and long-term impact of female-only versus female-and-male vaccination programmes. The current programme in females is predicted to result in a 68% reduction in male HPV 16 infections by 2050, leading to an estimated long-term reduction of 14% in rates of cancers of the head, neck and anogenital area. The estimated proportion of the maximum possible vaccine-conferred benefit to males from a female-and-male programme which will be achieved by female-only vaccination is 73% (range in probabilistic sensitivity analysis: 53-78%). The conclusion is that up to three-quarters of the maximum possible vaccination-conferred benefit to males due to reduced heterosexual transmission will be achieved by the existing female-only programme. (8) This demonstrates that if only heterosexual sex is considered, widespread vaccination of girls may be sufficient. However, where there is low coverage of HPV vaccination in girls and when MSM and people of both sexes with HIV are included in the programme, the evidence from the other studies summarised here indicates that young men should also be vaccinated.

(1.) Smith JS, Gilbert PA, Melendy A, et al. Age-specific prevalence of human papillomavirus infection in males: a global review. Journal of Adolescent Health 2011;48:540-52.

(2.) Banura C, Mirembe FM, Katahoire AR, et al. Epidemiology of HPV genotypes in Uganda and the role of the current preventive vaccines: a systematic review. Infectious Agents Cancer 2011;6(1):11.

(3.) Tachezy R, Smahelova J, Salakova M, et al. Human papillomavirus genotype distribution in Czech women and men with diseases etiologically linked to HPV. PLoS One 2011;6(7):e21913.

(4.) Dietz CA, Nyberg CR. Genital, oral, and anal human papillomavirus infection in men who have sex with men. Journal of the American Osteopath Association 2011;111 (3 Suppl.2):S19-S25.

(5.) Guiliano AR, Palefsky JM, Goldstone S, at al. Efficacy of quadrivalent HPV vaccine against HPV infection and disease in males. New England Journal of Medicine 2011;364(5):401-11.

(6.) Moreira ED, Palefsky JM, Giuliano AR, et al. Safety and reactogenicity of a quadrivalent human papillomavirus (types 6, 11, 16, 18) L1 viral-like-particle vaccine in older adolescents and young adults. Human Vaccines 2011;7(7).

(7.) Rehmeyer CJ. Male circumcision and human papillomavirus studies reviewed by infection stage and virus type. Journal of American Osteopath Association 2011;111(3 Suppl.2):S11-S18.

(8.) Smith MA, Lew JB, Walker RJ, et al. The predicted impact of HPV vaccination on male infections and male HPV-related cancers in Australia. Vaccine 2011;Mar 17. [Epub ahead of print]

DOI: 10.1016/S0968-8080(11)38592-8
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Title Annotation:ROUND UP: Human papillomavirus (HPV)
Publication:Reproductive Health Matters
Article Type:Report
Date:Nov 1, 2011
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