***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 Preexposure prophylaxis with antiretroviral agents has been shown to reduce the transmission of human immunodeficiency virus ( HIV ) among men who have sex with men ; however , the efficacy among heterosexuals is uncertain . METHODS We r and omly assigned HIV-seronegative men and women to receive either tenofovir disoproxil fumarate and emtricitabine ( TDF-FTC ) or matching placebo once daily . Monthly study visits were scheduled , and participants received a comprehensive package of prevention services , including HIV testing , counseling on adherence to medication , management of sexually transmitted infections , monitoring for adverse events , and individualized counseling on risk reduction ; bone mineral density testing was performed semiannually in a subgroup of participants . RESULTS A total of 1219 men and women underwent r and omization ( 45.7 % women ) and were followed for 1563 person-years ( median , 1.1 years ; maximum , 3.7 years ) . Because of low retention and logistic limitations , we concluded the study early and followed enrolled participants through an orderly study closure rather than exp and ing enrollment . The TDF-FTC group had higher rates of nausea ( 18.5 % vs. 7.1 % , P<0.001 ) , vomiting ( 11.3 % vs. 7.1 % , P=0.008 ) , and dizziness ( 15.1 % vs. 11.0 % , P=0.03 ) than the placebo group , but the rates of serious adverse events were similar ( P=0.90 ) . Participants who received TDF-FTC , as compared with those who received placebo , had a significant decline in bone mineral density . K65R , M184V , and A62V resistance mutations developed in 1 participant in the TDF-FTC group who had had an unrecognized acute HIV infection at enrollment . In a modified intention-to-treat analysis that included the 33 participants who became infected during the study ( 9 in the TDF-FTC group and 24 in the placebo group ; 1.2 and 3.1 infections per 100 person-years , respectively ) , the efficacy of TDF-FTC was 62.2 % ( 95 % confidence interval , 21.5 to 83.4 ; P=0.03 ) . CONCLUSIONS Daily TDF-FTC prophylaxis prevented HIV infection in sexually active heterosexual adults . The long-term safety of daily TDF-FTC prophylaxis , including the effect on bone mineral density , remains unknown . ( Funded by the Centers for Disease Control and Prevention and the National Institutes of Health ; TDF2 Clinical Trials.gov number , NCT00448669 . ) Background Bacterial vaginosis ( BV ) has been found to be associated with HIV acquisition and transmission . This is suggested to be due to higher HIV RNA levels in cervicovaginal fluids in women living with HIV ( WLWH ) with BV , as bacteria associated with BV may induce viral replication and shedding in the genital tract despite undetectable HIV RNA plasma viral load . We examined the prevalence and diagnostic predictors of BV and HIV-1 RNA vaginal shedding in women living with HIV ( WLWH ) in Denmark , taking into account the presence of human papillomavirus ( HPV ) and herpes viridae . Methods WLWH between 18–51 years were recruited from six Departments of Infectious Diseases in Denmark during enrolment in the SHADE cohort ; a prospect i ve cohort study of WLWH attending regular outpatient care .  BV was diagnosed by microscopy of vaginal swabs and PCR was used for detection of BV-associated bacteria , HPV , herpes viridae , and vaginal HIV viral load . Results Median age of the 150 included women was 41 years ; ethnicity was predominantly White ( 35 % ) or Black ( 47 % ) . The majority ( 96 % ) was on ART and had undetectable ( 85 % ) plasma HIV RNA ( < 40 copies/mL).BV was diagnosed in 32 % . Overall , 11 % had detectable vaginal HIV RNA . Both before and after adjustment for BV , age , ethnicity , plasma HIV RNA , CD4 cell count , herpes viridae and HPV , we found no significant predictors of HIV RNA vaginal shedding . Conclusion In well-treated WLWH , BV , herpes viridae or HPV do not predict vaginal HIV RNA shedding . This implies that HIV shedding does not seem to be increased by BV A r and omised trial was done to evaluate the impact of improved sexually transmitted disease ( STD ) case management at primary health care level on the  incidence of HIV infection in the rural Mwanza region of Tanzania .  HIV incidence was compared in six intervention communities and six pair-matched comparison communities . A r and om cohort of about 1000 adults aged 15 - 54 years from each community was surveyed at baseline and at follow-up 2 years later . Intervention consisted of establishment of an STD reference clinic , staff training , regular supply of drugs , regular supervisory visits to health facilities , and health education about STDs .  12,537 individuals were recruited .  Baseline HIV prevalences were 3.8 % and 4.4 % in the intervention and comparison communities , respectively . At follow-up , 8845 ( 71 % ) of the cohort were seen . Of those initially seronegative , the proportions seroconverting over 2 years were 48 of 4149 ( 1.2 % ) in the intervention communities and 82 of 4400 ( 1.9 % ) in the comparison communities . HIV incidence was consistently lower in the intervention communities in all six matched pairs . Allowing for the community-r and omised design and the effects of confounding factors , the estimated risk ratio was 0.58 ( 95 % CI 0.42 - 0.79 , p = 0.007 ) . No change in reported sexual behaviour was observed in either group . We conclude that improved STD treatment reduced HIV incidence by about 40 % in this rural population . This is the first r and omised trial to demonstrate an impact of a preventive intervention on HIV incidence in a general population Background : Asymptomatic Chlamydia trachomatis ( chlamydia ) and Neisseria gonorrhoeae ( gonorrhea ) infections pose diagnostic and control problems in developing countries . Methods : Participants in China , India , Peru , Russia , and Zimbabwe were screened for C. trachomatis and N. gonorrhoeae infections and symptoms . Results : A total of 18,014 participants were evaluated at baseline , 15,054 at 12 months , and 14,243 at 24 months . The incidence of chlamydia in men was 2.0 per 100 person years both from baseline to 12 months and from 12 to 24 months , and in women , 4.6 from baseline to 12 months and 3.6 from 12 to 24 months ; a range of 31.2 % to 100 % reported no symptoms across the 5 countries . The incidence of gonorrhea in men was 0.3 per 100 person years both from baseline to 12 months and from 12 to 24 months , and in women , 1.4 from baseline to 12 months and 1.1 from 12 to 24 months ; a range of 66.7 % to 100 % reported no symptoms . Being female , aged 18 to 24 years , and having more than 1 partner were associated with both the infections . In addition , being divorced , separated , or widowed was associated with gonorrhea . Being male , having 6 + years of education , and reporting only 1 partner were associated with having no symptoms among those infected with chlamydia . No variables correlated with asymptomatic gonorrhea among those infected . Conclusion : A high prevalence and incidence of asymptomatic sexually transmitted infections was identified among men and women in a wide variety of setting s. More effective programs are needed to identify and treat chlamydia and gonorrhea infections , especially among women , young adults , those with multiple partners , those repeatedly infected , and particularly those at risk without symptoms . The risk of transmission from persons with no symptoms requires further study The aim of this study was to investigate the effect of asymptomatic rectal bacterial sexually transmitted infections ( STIs ) on rectal HIV viral load ( VL ) . A prospect i ve cohort study of HIV-positive men who have sex with men attending a tertiary centre in London , UK , for their routine HIV care was performed . Forty-two HIV-positive men who have sex with men were recruited between January and August 2014 . In participants on antiretroviral therapy  ( ART ) , there was no significant difference in rectal VL in those with and without STI ( p = 0.4 ) . All rectal HIV VLs were below the limit of detection ( < 100 copies/µg of total RNA ) whether an STI was present or not . In those not on ART , rectal HIV VL was on average 0.6log10 lower post STI treatment . The presence of asymptomatic rectal chlamydia and gonorrhoea was not associated with increased rectal HIV VL in those fully suppressed on ART . In the context of effective ART , the presence of rectal gonorrhoea or chlamydia does not appear to increase rectal HIV VL and the risk of increased viral infectivity Background Neisseria gonorrhoeae ( gonorrhea ) could become untreatable in the near future . Indeed , while the treatment of symptomatic gonorrhea in core groups , such men who have sex with men ( MSM ) , is crucial for gonorrhea control programs , screening for and treating asymptomatic gonorrhea/Chlamydia trachomatis(chlamydia ) in MSM may contribute to antibiotic resistance in gonorrhea . In this systematic review , we aim to assess if there is evidence that screening MSM for gonorrhea/chlamydia is associated with a decline in the prevalence of these infections . Methods We conducted a systematic review in PubMed and Web of Science for relevant studies including uncontrolled observational studies and reported the results following the PRISMA guidelines . The change in estimated prevalences for chlamydia and gonorrhea across the different time points for 3 anatomical sites ( oral , urethral and anal ) were collected and examined . Results Twelve studies met our entry criteria . We were able to statistically assess the change in prevalence in 10 of 12 studies . In 3 studies , there was a significant increase in chlamydia prevalence , whereas for gonorrhea , 2 studies reported a significant increase and 2 others a decrease . Our review provides little evidence that screening for gonorrhea and chlamydia in MSM has an effect on the prevalence of these infections . No evidence was found that more frequent screening reduces prevalence more effectively than annual screening . Conclusions Our study was not able to provide evidence that screening for chlamydia and gonorrhea lowers the prevalence of these infections in MSM . R and omized controlled trials are required to assess the risks and benefits of gonorrhea/chlamydia screening in high- and low-risk MSM BACKGROUND Increased rates of sexually transmitted infections ( STIs ) have been reported among men who have sex with men . We aim ed to assess whether post-exposure prophylaxis ( PEP ) with doxycycline could reduce the incidence of STIs . METHODS All participants attending their scheduled visit in the open-label extension of the ANRS IPERGAY trial in France ( men aged 18 years or older having condomless sex with men and using pre-exposure prophylaxis for HIV with tenofovir disoproxil fumarate plus emtricitabine ) were eligible for inclusion in this open-label r and omised study . Participants were r and omly assigned ( 1:1 ) at a central site to take a single oral dose of 200 mg doxycycline PEP within 24 h after sex or no prophylaxis . The primary endpoint was the occurrence of a first STI ( gonorrhoea , chlamydia , or syphilis ) during the 10-month follow-up . The cumulative probability of occurrence of the primary endpoint was estimated in each group with the Kaplan-Meier method and compared with the log-rank test . The primary efficacy analysis was done on the intention-to-treat population , comprising all r and omised participants . All participants received risk-reduction counselling and condoms , and were tested regularly for HIV . This trial is registered with Clinical Trials.gov number , NCT01473472 . FINDINGS Between July 20 , 2015 , and Jan 21 , 2016 , we r and omly assigned 232 participants ( n=116 in the  doxycycline PEP group and n=116 in the  no-PEP  group ) who were followed up for a median of 8·7 months ( IQR 7·8 - 9·7 ) . Participants in the PEP group used a median of 680 mg doxycycline per month ( IQR 280 - 1450 ) . 73 participants presented with a new STI during follow-up , 28 in the PEP group ( 9-month probability 22 % , 95 % CI 15 - 32 ) and 45 in the no-PEP group ( 42 % , 33 - 5 
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RESULTS AND DISCUSSION S The diagnostic accuracy of urethral discharge and genital ulcer disease syndromes is relatively adequate .
Asymptomatic Chlamydia trachomatis ( CT ) and Neisseria gonorrhoeae ( NG ) infections limit the use of vaginal discharge and anorectal syndromes .
The pooled diagnostic accuracy of vaginal syndromic case management for CT/NG is low , result ing in high numbers of overtreatment and missed treatment .
The absolute effect of POCTs was reduced overtreatment and missed treatment .