***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Sexually transmitted infections ( STIs ) such as herpes simplex virus (HSV)-2 are associated with an increased risk of HIV infection . Human papillomavirus ( HPV ) is a common STI , but little is know about its role in HIV transmission . The objective of this study was to determine whether cervico-vaginal HPV infection increases the risk of HIV acquisition in women independent of other common STIs . Methods and Findings This prospect i ve cohort study followed 2040 HIV-negative Zimbabwean women ( average age 27 years , range 18–49 years ) for a median of 21 months . Participants were tested quarterly for 29 HPV types ( with L1 PCR primers ) and HIV ( antibody testing on blood sample s with DNA or RNA PCR confirmation ) . HIV incidence was 2.7 per 100 woman-years . Baseline HPV prevalence was 24.5 % , and the most prevalent HPV types were 58 ( 5.0 % ) , 16 ( 4.7 % ) , 70 ( 2.4 % ) , and 18 ( 2.3 % ) . In separate regression models adjusting for baseline variables ( including age , high risk partner , positive test for STIs , positive HSV-2 serology and condom use ) , HIV acquisition was associated with having baseline prevalent infection with HPV 58 ( aHR 2.13 ; 95 % CI 1.09–4.15 ) or HPV 70 ( aHR 2.68 ; 95 % CI 1.08–6.66 ) . In separate regression models adjusting for both baseline variables and time-dependent variables ( including HSV-2 status , incident STIs , new sexual partner and condom use ) , HIV acquisition was associated with concurrent infection with any non-oncogenic HPV type ( aHR 1.70 ; 95 % CI 1.02–2.85 ) , any oncogenic HPV type ( aHR 1.96 ; 95 % CI 1.16–3.30 ) , HPV 31 ( aHR 4.25 ; 95 % CI 1.81–9.97 ) or HPV 70 ( aHR 3.30 ; 95 % CI 1.50–7.20 ) . Detection of any oncogenic HPV type within the previous 6 months was an independent predictor of HIV acquisition , regardless of whether HPV status at the HIV acquisition visit was included ( aHR 1.95 ; 95 % CI 1.19–3.21 ) or excluded ( aHR 1.96 ; 95 % CI 1.02–2.85 ) from the analysis . Conclusions / Significance Cervico-vaginal HPV infection was associated with an increased risk of HIV acquisition in women , and specific HPV types were implicated in this association . The observational nature of our study precludes establishment of causation between HPV infection and HIV acquisition . However , given the high prevalence of HPV infection in women , further investigation of the role of HPV in HIV transmission is warranted Background Human papillomaviruses are the most common sexually transmitted infections , and genital warts , caused by HPV-6 and 11 , entail considerable morbidity and cost . The natural history of genital warts in relation to HIV-1 infection has not been described in African women . We examined risk factors for genital warts in a cohort of high-risk women in Burkina Faso , in order to further describe their epidemiology . Methods A prospect i ve study of 765 high-risk women who were followed at 4-monthly intervals for 27 months in Burkina Faso .  Logistic and Cox regression were used to identify factors associated with prevalent , incident and persistent genital warts , including HIV-1 serostatus , CD4 + count , and concurrent sexually transmitted infections . In a subset of 306 women , cervical HPV DNA was tested at enrolment . Results Genital wart prevalence at baseline was 1.6 % ( 8/492 ) among HIV-uninfected and 7.0 % ( 19/273 ) among HIV-1 seropositive women . Forty women ( 5.2 % ) experienced at least one incident GW episode . Incidence was 1.1 per 100 person-years among HIV-uninfected women , 7.4 per 100 person-years among HIV-1 seropositive women with a nadir CD4 + count > 200 cells/μL and 14.6 per 100 person-years among HIV-1 seropositive women with a nadir CD4 + count ≤200 cells/μL. Incident genital warts were also associated with concurrent bacterial vaginosis , and genital ulceration . Antiretroviral therapy was not protective against incident or persistent genital warts . Detection of HPV-6 DNA and abnormal cervical cytology were strongly associated with incident genital warts . Conclusions Genital warts occur much more frequently among HIV-1 infected women in Africa , particularly among those with low CD4 + counts . Antiretroviral therapy did not reduce the incidence or persistence of genital warts in this population Background While infections with human papillomavirus ( HPV ) are highly prevalent among sexually active young women in Ug and a , information on incidence , clearance and their associated risk factors is sparse . To estimate the incidence , prevalence and determinants of HPV infections , we conducted a prospect i ve follow-up study among 1,275 women aged 12 - 24 years at the time of recruitment . Women answered a question naire and underwent a pelvic examination at each visit to collect exfoliated cervical cells . The presence of 42 HPV types was evaluated in exfoliated cervical cells by a polymerase chain based ( PCR ) assay ( SPF10-DEIA LiPA ) . Results Three hundred and eighty ( 380 ) of 1,275 ( 29.8 % ) women were followed up for a median time of 18.5 months ( inter-quartile range 9.7 - 26.6 ) . Sixty-nine ( 69 ) women had incident HPV infections during 226 person-years of follow-up reflecting an incidence rate of 30.5 per 100 person-years . Incident HPV infections were marginally associated with HIV positivity ( RR = 2.8 , 95 % CI : 0.9 - 8.3 ) . Clearance for HPV type-specific infections was frequent ranging between 42.3 % and 100.0 % for high- and 50 % and 100 % for low-risk types . Only 31.2 % of women cleared all their infections . Clearance was associated with HIV negativity ( Adjusted clearance = 0.2 , 95 % CI : 0.1 - 0.7 ) but not with age at study entry , lifetime number of sexual partners and multiplicity of infections . The prevalence of low- grade squamous intraepithelial lesions ( LSILs ) was 53/365 ( 14.5 % ) . None of the women had a high- grade cervical lesion ( HSIL ) or cancer . Twenty-two ( 22 ) of 150 ( 14.7 % ) HPV negative women at baseline developed incident LSIL during follow-up . The risk for LSIL appeared to be elevated among women with HPV 18-related types compared to women not infected with those types ( RR = 3.5 , 95 % CI : 1.0 - 11.8 ) . Conclusions Incident HPV infections and type-specific HPV clearance were frequent among our study population of young women . These results underscore the need to vaccinate pre-adolescent girls before initiation of sexual activity BACKGROUND Male circumcision could provide substantial protection against acquisition of HIV-1 infection . Our aim was to determine whether male circumcision had a protective effect against HIV infection , and to assess safety and changes in sexual behaviour related to this intervention . METHODS We did a r and omised controlled trial of 2784 men aged 18 - 24 years in Kisumu , Kenya . Men were r and omly assigned to an intervention group ( circumcision ; n=1391 ) or a control group ( delayed circumcision , 1393 ) , and assessed by  HIV testing , medical examinations , and behavioural interviews during follow-ups at 1 , 3 , 6 , 12 , 18 , and 24 months . HIV seroincidence was estimated in an intention-to-treat analysis . This trial is registered with Clinical Trials.gov , with the number NCT00059371 . FINDINGS The trial was stopped early on December 12 , 2006 , after a third interim analysis review ed by the data and safety monitoring board . The median length of follow-up was 24 months . Follow-up for HIV status was incomplete for 240 ( 8.6 % ) participants . 22 men in the intervention group and 47 in the control group had tested positive for HIV when the study was stopped . The 2-year HIV incidence was 2.1 % ( 95 % CI 1.2 - 3.0 ) in the circumcision group and 4.2 % ( 3.0 - 5.4 ) in the control group ( p=0.0065 ) ; the relative risk of HIV infection in circumcised men was 0.47 ( 0.28 - 0.78 ) , which corresponds to a reduction in the risk of acquiring an HIV infection of 53 % ( 22 - 72 ) . Adjusting for non-adherence to treatment and excluding four men found to be seropositive at enrollment , the protective effect of circumcision was 60 % ( 32 - 77 ) . Adverse events related to the intervention ( 21 events in 1.5 % of those circumcised ) resolved quickly . No behavioural risk compensation after circumcision was observed . INTERPRETATION Male circumcision significantly reduces the risk of HIV acquisition in young men in Africa . Where appropriate , voluntary , safe , and affordable circumcision services should be integrated with other HIV preventive interventions and provided as expeditiously as possible BACKGROUND Studies analyzing the impact of combination antiretroviral therapy ( cART ) on cervical infection with high-risk human papillomavirus ( HR-HPV ) have generated conflicting results . We assessed the long-term impact of cART on persistent cervical HR-HPV infection in a very large cohort of 652 women who underwent follow-up of HIV infection for a median duration of 104 months . METHODS Prospect i ve cohort of HIV-infected women undergoing HIV infection follow-up who had HR-HPV screening and cytology by Papanicolaou smear performed yearly between 2002 and 2011 . RESULTS At baseline , the median age was 38 years , the race/ethnic origin was sub-Sarahan Africa for 84 % , the median CD4(+ ) T-cell count was 426 cells/µL , 79 % were receiving cART , and the HR-HPV prevalence was 43 % . The median interval of having had an HIV load of < 50 copies/mL was 40.6 months at the time of a HR-HPV-negative test result , compared with 17 months at the time of a HR-HPV-positive test result ( P < .0001 , by univariate analysis ) . The median interval of having had a CD4(+ ) T-cell count of > 500 cells/µL was 18.4 months at the time of a HR-HPV-negative test result , compared with 4.45 months at the time of a HR-HPV-positive test result ( P < .0001 ) . In multivariate analysis , having had an HIV load of < 50 copies/mL for > 40 months ( odds ratio [ OR ] , 0.81 ; 95 % confidence interval [ CI ] , .76-.86 ; P < .0001 ) and having had a CD4(+ ) T-cell count of > 500 cells/µL for > 18 months ( OR , 0.88 ; 95 % CI , .82-.94 ; P = .0002 ) were associated with a significantly decreased risk of HR-HPV infection . CONCLUSION Sustained HIV suppression for > 40 months and a sustained CD4(+ ) T-cell count of > 500 cells/µL for > 18 months are independently and significantly associated with a decreased risk of persistent cervical HR-HPV infection BACKGROUND High rates of persistence of human papillomavirus ( HPV ) infection have been reported for adult women with human immunodeficiency virus ( HIV ) infection . Although most women are first infected with HPV during adolescence , persistence of specific HPV types has not been carefully examined among HIV-infected adolescents . The objective of this study was to examine the rates of and risk factors for persistence of HPV types among HIV-infected and -uninfected adolescent girls . METHODS This is a prospect i ve cohort study of female adolescents , aged 13 - 18 years , participating in the Reaching for Excellence in Adolescent Care and Health project , a national study of HIV-infected and -uninfected adolescents . The main outcome measured was type-specific loss of initial HPV DNA detected . Loss of HPV DNA was defined for the following categories of HP 
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There was more evidence of publication bias in review 2 , and somewhat greater risk of confounding in studies included in review 1 .
There was some evidence that adjustment for key confounders strengthened the associations for review 2 .
Misclassification bias by HIV/HPV exposure status could also have biased estimates toward the null .
These results provide evidence for synergistic HIV and HPV interactions of clinical and public health relevance .
Although observational studies can never perfectly control for residual confounding , the evidence presented here lends further support for the presence of biological interactions between HIV and HPV that have a strong plausibility