***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 Herpes Simplex Virus type 2 ( HSV-2 ) has public health importance as a leading cause of genital ulcers , a co-factor in HIV-1 acquisition and transmission and as a cause of neonatal herpes infections . Little is known of its epidemiology and burden in Coastal Kenya . Methods We screened plasma sample s for HSV-2 infection from 826 women aged 15 - 34 years who participated in an HIV-1 survey in Kilifi in 2004 . The sample comprised 563 women selected r and omly from a demographic surveillance system ( DSS ) and 263 women who presented for voluntary counseling and testing ( VCT ) .  Predictors for HSV-2 seropositivity were determined using multivariate logistic regression . The incidence of HSV-2 infection and risk of neonatal herpes were estimated by a simple catalytic model fitted to age-seroprevalence data . Results HSV-2 prevalence was 32 % in the DSS recruits vs. 44 % in the VCT recruits ( P < 0.001 ) , while , HIV-1 prevalence was 8 % in the DSS recruits vs. 12 % in the VCT recruits ( P = 0.12 ) . Independent risk factors for HSV-2 infection in all women were : older age ( 30 - 34 years ; odds ratio ( OR ) 10.5 , 95 % confidence interval ( CI ) : 5.2 - 21.0 ) , recruitment from VCT ( OR 1.5 , 95 % CI : 1.1 - 2.1 ) , history of genital ulcers ( OR 1.7 , 95 % CI : 1.2 - 2.3 ) and HIV infection ( OR 2.7 , 95 % CI : 1.6 - 4.6 ) . Education beyond primary ( OR 0.7 , 95 % CI : 0.5 - 0.9 ) was inversely associated with HSV-2 infection . In the DSS sample , HSV-2 incidence was estimated at 4 cases ( 95 % CI : 3.3 - 4.4 ) per 100 women per year , 17 cases ( 95 % CI : 16 - 18 ) per 1,000 pregnancies per year and 33 neonatal cases ( 95 % CI : 31 - 36 ) per 100,000 births per year . Conclusions HSV-2 transmission is rapid following the onset of sexual activity and likely to result in a significant burden of genital ulcer disease . Nevertheless , the burden of neonatal HSV-2 can be predicted to be low . Educating young women about HSV-2 infection may help in reducing its burden in this semi-urban population BACKGROUND Prospect i ve studies of herpes simplex virus type 2 ( HSV-2 ) infection in discordant couples have shown a low rate of transmission . However , unlike partners with genital herpes in prospect ively monitored couples , most persons who transmit genital herpes are not aware of having the infection . METHODS Because HSV has a short incubation period and most persons who acquire genital herpes can identify the transmitting partner , a time-to-event design was used to assess risks of HSV acquisition among patients with newly acquired genital herpes . RESULTS Among 199 persons with laboratory-documented newly acquired genital herpes , the median duration of the sexual relationship with the transmitting partner was 3.5 months , and the median number of sex acts  before transmission  was 40 . The median time to HSV-2 acquisition was greater among participants whose partners disclosed that they had genital herpes , compared with participants whose partners did not disclose their status ( 270 vs. 60 days ; P = .03 ) . In multivariate models , having a partner who disclosed that he or she had genital herpes remained a strong protective factor against genital HSV-2 acquisition ( hazard ratio , 0.48 [ 95 % confidence interval , 0.25 - 0.91 ] ) . CONCLUSION These findings suggest that testing persons with HSV type-specific serologic assays and encouraging disclosure may result in a decreased risk of HSV-2 transmission to sex partners OBJECTIVE To estimate the global prevalence and incidence of herpes simplex virus type 2 ( HSV-2 ) infection in 2003 . METHODS A systematic review was undertaken of published seroprevalence surveys describing the prevalence or incidence of HSV-2 by age and gender . For each of 12 regions , pooled prevalence values by age and gender were generated in a r and om-effect model . HSV-2 incidence was then estimated from these pooled values using a constant-incidence model . Values of the HSV-2 seroprevalence from the model fits were applied to the total population to estimate the numbers of people infected . FINDINGS The total number of people aged 15 - 49 years who were living with HSV-2 infection worldwide in 2003 is estimated to be 536 million , while the total number of people who were newly infected with HSV-2 in 2003 is estimated to be 23.6 million . While the estimates are limited by poor availability of data , general trends are evident . For example , more women than men were infected , and the number infected increased with age . Although prevalence varied substantially by region , predicted prevalence was mostly higher in developing regions than developed regions . CONCLUSION The prevalence of HSV-2 is relatively easy to measure since infection is lifelong and has a specific serological test . The burden of disease is less easy to quantify . Despite the often sparse data on which these estimates are based , it is clear that HSV-2 infection is widespread . The dramatic differences in prevalence between regions are worthy of further exploration Objective : We assessed the protective effect of medical male circumcision ( MMC ) against HIV , herpes simplex virus type 2 ( HSV-2 ) , and genital ulcer disease ( GUD ) incidence . Design : Two thous and , seven hundred and eighty-seven men aged 18–24 years living in Kisumu , Kenya were r and omly assigned to circumcision  ( n=1391 ) or delayed circumcision  ( n = 1393 ) and assessed by  HIV and HSV-2 testing and medical examinations during follow-ups at 1 , 3 , 6 , 12 , 18 , and 24 months . Methods : Cox regression estimated the risk ratio of each outcome ( incident HIV , GUD , HSV-2 ) for circumcision status and multivariable models estimated HIV risk associated with HSV-2 , GUD , and circumcision status as time-varying covariates . Results : HIV incidence was 1.42 per 100 person-years . Circumcision was 62 % protective against HIV [ risk ratio = 0.38 ; 95 % confidence interval ( CI ) 0.22–0.67 ] and did not change when controlling for HSV-2 and GUD ( risk ratio = 0.39 ; 95 % CI 0.23–0.69 ) . GUD incidence was halved among circumcised men ( risk ratio = 0.52 ; 95 % CI 0.37–0.73 ) . HSV-2 incidence did not differ by circumcision status ( risk ratio = 0.94 ; 95 % CI 0.70–1.25 ) . In the multivariable model , HIV seroconversions were tripled ( risk ratio = 3.44 ; 95 % CI 1.52–7.80 ) among men with incident HSV-2 and seven times greater ( risk ratio = 6.98 ; 95 % CI 3.50–13.9 ) for men with GUD . Conclusion : Contrary to findings from the South African and Ug and an trials , the protective effect of  MMC against HIV was independent of GUD and HSV-2 , and MMC had no effect on HSV-2 incidence . Determining the causes of GUD is necessary to reduce associated HIV risk and to underst and how circumcision confers protection against GUD and HIV Vaginal Gel Versus HIV HIV prevention technologies for women are urgently needed , especially in sub-Saharan Africa where young women bear the greatest burden of the HIV epidemic . Abdool Karim et al. ( p. 1168 ; published online 19 July ) present the results of the CAPRISA 004 r and omized control trial . The nearly 3-year-long trial , conducted in urban and rural South African women , tested the efficacy of a vaginal gel containing the antiretroviral drug tenofovir in preventing HIV infection . The dosing strategy required application of the gel both before and after coitus , and with this regime HIV infection was reduced by approximately 39 % overall , by 54 % in women with high adherence to the protocol , and with no increase in overall adverse event rates . Tenofovir in a vaginal gel formulation shows significant protection against HIV infection in a r and omized control trial . The Centre for the AIDS Program of Research in South Africa ( CAPRISA ) 004 trial assessed the effectiveness and safety of a 1 % vaginal gel formulation of tenofovir , a nucleotide reverse transcriptase inhibitor , for the prevention of HIV acquisition in women . A double-blind , r and omized controlled trial was conducted comparing  tenofovir gel ( n = 445 women ) with  placebo gel ( n = 444 women ) in sexually active , HIV-uninfected 18- to 40-year-old women in urban and rural KwaZulu-Natal , South Africa .  HIV serostatus , safety , sexual behavior , and gel and condom use were assessed at monthly follow-up visits for 30 months . HIV incidence in the tenofovir gel arm was 5.6 per 100 women-years ( person time of study observation ) ( 38 out of 680.6 women-years ) compared with 9.1 per 100 women-years ( 60 out of 660.7 women-years ) in the placebo gel arm ( incidence rate ratio = 0.61 ; P = 0.017 ) . In high adherers ( gel adherence > 80 % ) , HIV incidence was 54 % lower ( P = 0.025 ) in the tenofovir gel arm . In intermediate adherers ( gel adherence 50 to 80 % ) and low adherers ( gel adherence < 50 % ) , the HIV incidence reduction was 38 and 28 % , respectively . Tenofovir gel  reduced HIV acquisition by an estimated 39 % overall , and by 54 % in women with high gel adherence . No increase in the overall adverse event rates was observed . There were no changes in viral load and no tenofovir resistance in HIV seroconverters . Tenofovir gel could potentially fill an important HIV prevention gap , especially for women unable to successfully negotiate mutual monogamy or condom use Background In addition to protecting against HIV acquisition , antiretroviral preexposure prophylaxis ( PrEP ) using topical 1 % tenofovir gel reduced Herpes simplex virus type 2 ( HSV-2 ) acquisition by 51 % among women in the CAPRISA 004 study . We examined the effect of daily oral emtricitabine/tenofovir ( FTC/TDF ) PrEP on HSV-2 seroincidence and ulcer occurrence among men who have sex with men ( MSM ) in the iPrEx trial . Methods HSV-2 serum  testing was performed at screening and every six months . Among HSV-2-seronegative individuals , we used Cox regression models to estimate hazard ratios ( HRs ) of HSV-2 seroincidence associated with r and omization to FTC/TDF . We used multiple imputation and Cox regression to estimate HRs for HSV-2 seroincidence accounting for drug exposure . We assessed ulcer occurrence among participants with prevalent or incident HSV-2 infection . Results Of the 2,499 participants , 1383 ( 55.3 % ) tested HSV-2-seronegative at baseline , 892 ( 35.7 % ) tested positive , 223 ( 8.9 % ) had indeterminate tests , and one test was not done . Of the 1,347 HSV-2-seronegative participants with follow-up , 125 ( 9.3 % ) had incident HSV-2 infection ( 5.9 per 100 person-years ) . Compared with participants receiving placebo , there was no difference in HSV-2 seroincidence among participants receiving FTC/TDF ( HR 1.1 , 95 % CI : 0.8–1.5 ; P = 0.64 ) or among participants receiving FTC/TDF with a concentration of tenofovir diphosphate > 16 per million viable cells ( HR 1.0 , 95 % CI : 0.3–3.5 ; P = 0.95 ) . Among participants with HSV-2 infection , the proportion with ≥1 moderate or severe ulcer adverse event was twice as high in the placebo vs. active arm ( 5.9 % vs. 2.9 % , P = 0.02 ) , but there were no differences in the proportions with ≥1 clinical examination during which perianal or groin ulcers were identified . Conclusions Tenofovir in daily oral FTC/TDF PrEP may reduce the occurrence of ulcers in individuals with HSV-2 infection but does not protect against HSV-2 incidence among MSM Background : An association has been demonstrated between herpes simplex type 2 ( HSV-2 ) and HIV infection among men , but prospect i ve studies in women have yielded mixed results . Objective : To estimate the effects of prevalent and incident HSV-2 infection on subsequent 
    Output:
    
Risk factors for HSV-2 in women included prevalent human immunodeficiency virus ( HIV ) infection  , younger age at sexual initiation , and sexual activity .
Among men , condom use and circumcision had a protective effect , whereas prevalent HIV increased the risk of HSV-2 acquisition .