***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: The purpose of this study was to evaluate the effects of a brief intervention programme on STD knowledge , condom use and gonorrhoea incidence among sex workers in Singapore . A controlled before- and -after study design with non-r and om assignment of sex workers was used , supplemented by multivariate analysis to adjust for baseline differences .  Control ( n = 221 , denoted C1 ) and experimental ( n = 221 , denoted E1 ) groups were interviewed on 2 occasions 3 months apart . Two supplementary groups were interviewed once each at the end of the 3-month period ( n = 145 who had received the intervention and n = 151 who had not ) . Basic knowledge of STD symptoms and HIV transmission was high in all groups . There were misconceptions about casual transmission of HIV which improved dramatically at the second interview for group El ( from 37–56 % correct responses to 82–90 % ) . Overall condom use was high ( about 75 % ) and did not change after the intervention . Gonorrhoea rates were correspondingly low ( 0.4 episodes/worker/year ) and also did not change . This brief intervention improved the STD knowledge of sex workers . However , behaviour as measured by reported condom use and gonorrhoea incidence did not change . Implication s for future intervention programmes are discussed Objective : To describe the impact of a repeating behavioural intervention focused on preventive education and provision of STD testing and treatment services to female sex workers . Methods : A prospect i ve cohort study of 966 sex workers ( first of its kind in China ) was conducted in Guangzhou from March 1998 to October 1999 . At each visit information was collected on sexual behaviour , condom use and knowledge about HIV transmission and condom use , education was given , STD were diagnosed , and treatment was provided free of charge . We evaluated trends in condom use , knowledge about HIV transmission and condom use , and STD incidences . Generalised estimating equations were applied to control for repeated measurements . Results : The proportion of consistent condom use increased from the intake through the third follow up visit ( from 30 % to 81 % ) , as well as the proportion of having good knowledge on HIV transmission ( 4.3 % to 98.6 % ) and condom use ( 23.6 % to 79.3 % ) . The incidence of gonorrhoea , trichomoniasis , and chlamydia decreased over each follow up visit ; from 17.5/100 person years ( PY ) , 22.4/100PY , 65.9/100PY at the first follow up visit to 5.1/100PY , 3.0/100PY , 16.1/100PY at the third follow up visit , for each STD respectively . Conclusions : STD care and prevention programmes targeting sex workers are feasible in China and , more importantly , intervention consisting of prevention education and STD care is likely to reduce unprotected sexual behaviour and STD incidence in this group at high risk for HIV and other STD infection OBJECTIVE To determine the efficacy of the nonoxynol 9 contraceptive sponge in preventing  sexual acquisition of the human immunodeficiency virus ( HIV ) .  DESIGN Prospect i ve , r and omized placebo-controlled trial . SETTING Research clinic for prostitutes in Nairobi , Kenya . PATIENTS AND INTERVENTIONS One hundred thirty-eight HIV-seronegative women were enrolled , of whom 74 were assigned to  nonoxynol 9 sponge use and 64 to  placebo  use . These two groups did not significantly differ with respect to demographic characteristics , sexual practice s , or prevalence of genital infections at enrollment , except for a lower number of sex partners per week and a higher initial prevalence of genital ulcers among women assigned to nonoxynol 9 sponge use . Among the 116 women who returned for follow-up , the mean duration s of follow-up were 14 and 17 months for the two groups , respectively . MAIN OUTCOME MEASURE HIV seroconversion . RESULTS Nonoxynol 9 sponge use was associated with an increased frequency of genital ulcers ( relative risk [ RR ] , 3.3 ; P less than .0001 ) and vulvitis ( RR , 3.3 ; P less than .0001 ) and a reduced risk of gonococcal cervicitis ( RR , 0.4 ; P less than .0001 ) . Twenty-seven ( 45 % ) of 60 women in the nonoxynol 9 sponge group and 20 ( 36 % ) of 56 women in the placebo group developed HIV antibodies . The hazard ratio for the association between nonoxynol 9 sponge use and HIV seroconversion was 1.7 ( 95 % confidence interval [ CI ] , 0.9 to 3.0 ) . Using multivariate analysis to control for the presence of genital ulcers at enrollment , the adjusted hazard ratio for the association between  nonoxynol 9 sponge use and seroconversion was 1.6 ( 95 % CI , 0.8 to 2.8 ) . CONCLUSIONS Genital ulcers and vulvitis occurred with increased frequency in nonoxynol 9 sponge users . We were unable to demonstrate that nonoxynol 9 sponge use was effective in reducing the risk of HIV infection among highly exposed women Background and Objective : The Sonagachi Project in Calcutta , India , organized sex workers to improve working conditions . Goal : To compare rates of sexually transmitted diseases between the  Sonagachi Project  and other areas in which only the National AIDS Control Organization ( NACO ) interventions were implemented . Study : A cross-sectional survey of r and omly selected female sex workers . Results : There was no difference in the prevalence of all STDs between the 2 areas ; both were lower than reported in other surveys in 1992 . Analysis using propensity scores also failed to demonstrate any difference . The number of preventive activities was similar in the Sonagachi and NACO-only areas but was more prevalent than in 1992 . Sex workers in the Sonagachi area had better treatment-seeking behavior and attitudes . Both the Sonagachi and NACO strategies have result ed in lower STD rates , but the Sonagachi Project also increased the proportion who had an optimistic attitude and increased prevention and treatment-seeking behavior Objective To assess the short- and long-term impact of a 6-month pilot intervention program on condom use among prostitutes in Accra , Ghana . Design The 4-year prospect i ve study follows-up cohorts enrolled in the intervention in 1987 and 1988 , comparing condom use in 1991 with that among a comparison group not enrolled in the intervention . Setting The community-based intervention was initiated in Accra , Ghana in 1987 . Participants Self-identified female prostitutes who volunteered participation . InterventionThe educational intervention used local health workers to train and support selected prostitutes to be health educators and condom distributers to their peers . Outcome measures Self-reported condom use with clients . Results Reported condom use increased dramatically between 1987 and 1988 during the first 6 months of the intervention . In 1991 , after 3 years of program relapse , 107 ( 43 % ) of the 248 women who had enrolled in 1987 or 1988 were still in prostitution and located for interview . Their level of condom use in 1991 was higher than pre-enrollment but similar to use among prostitutes never enrolled . Sixty-four per cent of those followed-up reported always using condoms with clients in 1991 . These ‘ always users ' were more likely to have maintained informal contact with project staff , know that HIV can be transmitted by healthy clients , and report that clients frequently initiate condom use . Conclusions Findings support the development of long-range educational strategies that recognize the career longevity of prostitutes , available channels for informal program diffusion , individual changes in condom use over time , and the role of clients in condom negotiation BACKGROUND Nonoxynol-9 ( rINN , nonoxinol-9 ) is an over-the-counter spermicide that has in-vitro anti-HIV-1 activity . Results of studies of its effectiveness in prevention of  HIV-1 infection in women have been inconclusive . We aim ed to assess effectiveness of this vaginal gel . METHODS We did a r and omised , placebo-controlled , triple-blinded , phase 2/3 trial with COL-1492 , a nonoxynol-9 vaginal gel , in 892 female sex workers in four countries : Benin , Côte d'Ivoire , South Africa , and Thail and . 449 women were r and omly allocated  nonoxynol-9 and 443 placebo . Primary endpoint was incident HIV-1 infection . Secondary endpoints included Neisseria gonorrhoeae and Chlamydia trachomatis infections . Analysis was by intention to treat . FINDINGS 765 women were included in the primary analysis .  HIV-1 frequency in nonoxynol-9 users was 59 ( 16 % ) of 376 compared with 45 ( 12 % ) [ corrected ] of 389 in placebo users ( 402.5 vs 435.0 woman-years ; hazard ratio adjusted for centre 1.5 ; 95 % CI 1.0 - 2.2 ; p=0.047 ) . 239 ( 32 % ) women reported use of a mean of more than 3.5 applicators per working day , and in these women , risk of HIV-1 infection in nonoxynol-9 users was almost twice that in placebo users ( hazard ratio 1.8 ; 95 % CI 1.0 - 3.2 ) . 516 ( 68 % ) women used the gel less frequently than 3.5 times a day , and in these , risk did not differ between the two treatments . No significant effect of nonoxynol-9 on N gonorrhoeae ( 1.2 ; 0.9 - 1.6 ) or C trachomatis ( 1.2 ; 0.8 - 1.6 ) infections was reported . INTERPRETATION This study did not show a protective effect of COL-1492 on HIV-1 transmission in high-risk women . Multiple use of nonoxynol-9 could cause toxic effects enhancing HIV-1 infection . This drug can no longer be deemed a potential HIV-1-prevention method . Assessment of other microbicides should continue Summary : To test the efficacy of a sustainable community-level HIV intervention  among sex workers , the Sonagachi Project was replicated , including community organizing and advocacy , peer education , condom social marketing , and establishment of a health clinic .  Sex workers were r and omly selected in 2 small urban communities in northeastern India ( n = 100 each ) and assessed every 5–6 months over 15 months ( 85 % retention ) . Overall condom use increased significantly in the intervention community ( 39 % ) compared with the control community ( 11 % ) , and the proportion of consistent condom users increased 25 % in the intervention community compared with a 16 % decrease in the control community . This study supports the efficacy of the Sonagachi model intervention in increasing condom use and maintaining low HIV prevalence among sex workers A community based sample survey of sexually transmitted diseases and Human Immuno deficiency Virus infection was carried out among commercial sex workers of a red-light area in Calcutta . In this paper socio-demographic aspects of sex workers are discussed . For the survey , 450 sex workers were selected by r and om sampling method . Among the sex workers surveyed , 84.89 per cent were in the age group 15 - 29 years . Lowest age was 13 years and mean age was 23.12 years . Large number of sex workers were from Nepal ( 15.11 per cent ) and Bangladesh ( 11.78 per cent ) . About 38 per cent were from three districts of West Bengal bordering Bangladesh . About 84.44 per cent of the sex workers were illiterate . Extreme poverty forced 49.10 per cent to choose this profession and family disturbances led 21.56 per cent to this profession . Almost all sex workers ( 448 ) had addiction , alcohol being taken regularly by 81.11 per cent . Number of clients of sex workers varied from 2 to 10 , average being 3 . About 67.33 per cent gave history of pregnancy , 46 per cent had abortion and 41.11 per cent had living children . About 27.11 per cent took pre caution against pregnancy regularly . Use of  oral pills  was found to be the most common practice against pregnancy ( 13.65 per cent ) , followed by ligation ( 11.56 per cent ) . Only 1.11 per cent reported that their clients used condom regularly Our objectives were to describe the baseline findings of a trial of antibiotic prophylaxis to prevent sexually transmitted infections ( STIs ) and HIV-1 in a cohort of Nairobi female sex workers ( FSWs ) . A question naire was administered and a medical examination was performed . HIV-negative women were r and omly assigned to either one gram azithromycin or placebo monthly . Mean age of the 318 women was 32 years , mean duration of sex work 7 years and mean number of clients was 4 per day .  High-risk behaviour was frequent : 14 % practised anal intercourse , 23 % sex during menses , and 3 % used intravenous drugs . While 20 % reported condom use with all clients , 37 % never use condoms . However , STI prevalence was relatively low : HIV-1 27 % , bacterial vaginosis 46 % , Trichomonas vaginalis 13 % , Neisser 
    Output:
    
Despite method ological limitations , the evidence suggested that combining sexual risk reduction , condom promotion and improved access to STI treatment reduces HIV and STI acquisition in sex workers receiving the intervention .
Strong evidence that regular STI screening or periodic treatment of STIs confers additional protection against HIV was lacking .
It appears that structural interventions , policy change or empowerment of sex workers , reduce the prevalence of STIs and HIV .
There is some evidence for the efficacy of multi-component interventions , and /or structural interventions .