***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: This paper used qualitative methods to explore experiences of men who have sex with men and female sex workers in Nairobi and Mtwapa , Kenya , who used oral pre-exposure prophylaxis ( PrEP ) for HIV prevention as part of a four-month trial of safety , acceptability and adherence . Fifty-one of 72 volunteers who took part in a r and omized , placebo-controlled , blinded trial that compared daily and intermittent dosage of PrEP underwent qualitative assessment s after completing the trial . Analyses identified three themes : ( i ) acceptability of PrEP  was high , i.e. side effects were experienced early in the study but diminished over time , however characteristics of pills could improve comfort and use ; ( ii ) social impacts such as stigma , rumors , and relationship difficulties due to being perceived as HIV positive were prevalent ; ( iii ) adherence was challenged by complexities of daily life , in particular post-coital dosing adherence suffered from alcohol use around time of sex , mobile population s , and transactional sex work . These themes resonated across dosing regimens and gender , and while most participants favored the intermittent dosing schedule , those in the intermittent group noted particular challenges in adhering to the post-coital dose . Culturally appropriate and consistent counseling addressing these issues may be critical for PrEP effectiveness Background : Intimate partner violence ( IPV ) is associated with higher HIV incidence , reduced condom use , and poor adherence to antiretroviral therapy and other medications . IPV may also affect adherence to pre-exposure prophylaxis ( PrEP ) . Methods : We analyzed data from 1785 HIV-uninfected women enrolled in a clinical trial of PrEP among African HIV serodiscordant couples . Experience of verbal , physical , or economic IPV was assessed at monthly visits by face-to-face interviews . Low PrEP adherence was defined as clinic-based pill count coverage < 80 % or plasma tenofovir levels < 40 ng/mL. The association between IPV and low adherence was analyzed using generalized estimating equations , adjusting for potential confounders . In-depth interview transcripts were examined to explain how IPV could impact adherence . Results : Sixteen percent of women reported IPV during a median of 34.8 months of follow-up ( interquartile range 27.0–35.0 ) . Overall , 7 % of visits had pill count coverage < 80 % , and 32 % had plasma tenofovir < 40 ng/mL. Women reporting IPV in the past 3 months had increased risk of low adherence by pill count ( adjusted risk ratio 1.49 , 95 % confidence interval : 1.17 to 1.89 ) and by plasma tenofovir ( adjusted risk ratio 1.51 , 95 % confidence interval : 1.06 to 2.15 ) . Verbal , economic , and physical IPV were all associated with low adherence . However , the impact of IPV diminished and was not statistically significant 3 months after the reported exposure . In qualitative interviews , women identified several ways in which IPV affected adherence , including stress and forgetting , leaving home without pills , and partners throwing pills away . Conclusions : Women who reported recent IPV in the Partners PrEP Study were at increased risk of low PrEP adherence . Strategies to mitigate PrEP nonadherence in the context of IPV should be evaluated Background In VOICE , a multisite HIV pre-exposure prophylaxis ( PrEP ) trial , plasma drug levels pointed to widespread product nonuse , despite high adherence estimated by self-reports and clinic product counts . Using a socio-ecological framework ( SEF ) , we explored socio-cultural and context ual factors that influenced participants ’ experience of daily vaginal gel and oral tablet regimens in VOICE . Methods In Johannesburg , a qualitative ancillary study was concurrently conducted among r and omly selected VOICE participants assigned to in-depth interviews ( n = 41 ) , serial ethnographic interviews ( n = 21 ) , or focus group discussion s ( n = 40 ) . Audiotaped interviews were transcribed , translated , and coded thematically for analysis . Results Of the 102 participants , the mean age was 27 years , and 96 % had a primary sex partner with whom 43 % cohabitated . Few women reported lasting nonuse , which they typically attributed to missed visits , lack of product replenishments , and family-related travel or work . Women acknowledged occasionally skipping or mistiming doses because they forgot , were busy , felt lazy or bored , feared or experienced side effects . However , nearly all knew or heard of other study participants who did not use products daily . Three overarching themes emerged from further analyses : ambivalence toward research , preserving a healthy status , and managing social relationships . These themes highlighted the profound and complex meanings associated with participating in a blinded HIV PrEP trial and taking antiretroviral-based products . The unknown efficacy of products , their connection with HIV infection , challenges with daily regimen given social risks , lack of support – from partners and significant others– and the relationship tradeoffs entailed by using the products appear to discourage adequate product use . Conclusions Personal acknowledgment of product nonuse was challenging . This qualitative inquiry highlighted key influences at all SEF levels that shaped women ’s perceptions of trial participation and experiences with investigational products . Whether these impacted women ’s behaviors and may have contributed to ineffective trial results warrants further investigation We compared adherence to and acceptability of daily topical and oral formulations of tenofovir ( TFV ) used as pre-exposure prophylaxis ( PrEP ) for HIV prevention among women in South Africa , Ug and a and the United States . 144 sexually active , HIV-uninfected women participated in a cross-over study of three regimens : oral tablet , vaginal gel , or both . We tested for differences in adherence and evaluated product acceptability . Self-reported adherence for all regimens was high ( 94 % ) , but serum TFV concentrations indicated only 64 % of participants used tablets consistently . Most women in the U.S. ( 72 % ) favored tablets over gel ; while preferences varied at the African sites ( 42 % preferred gel and 40 % tablets ) . Findings indicate a role for oral and vaginal PrEP formulations and highlight the importance of integrating pharmacokinetics-based adherence assessment in future trials . Biomedical HIV prevention interventions should consider geographic and cultural experience with product formulations , partner involvement , and sexual health benefits that ultimately influence use Background Although significant progress has been made in clinical trials of women-controlled methods of HIV prevention such as microbicides and Pre-exposure Prophylaxis ( PrEP ) , low adherence to experimental study products remains a major obstacle to being able to establish their efficacy in preventing HIV infection . One factor that influences adherence is the ability of trial participants to attend regular clinic visits at which trial products are dispensed , adherence counseling is administered , and participant safety is monitored . We conducted a qualitative study of the social context ual factors that influenced adherence in the VOICE ( MTN-003 ) trial in Johannesburg , South Africa , focusing on study participation in general , and study visits in particular . Methods The research used qualitative method ologies , including in-depth interviews ( IDI ) , serial ethnographic interviews ( EI ) , and focus group discussion s ( FGD ) among a r and om sub- sample of 102 female trial participants , 18 to 40 years of age . A socio-ecological framework that explored those factors that shaped trial participation and adherence to study products , guided the analysis . Key codes were developed to st and ardize subsequent coding and a node search was used to identify texts relating to obstacles to visit adherence . Our analysis includes coded transcripts from seven FGD ( N = 40 ) , 41 IDI , and 64 serial EI ( N = 21 women ) . Results Women ’s kinship , social , and economic roles shaped their ability to participate in the clinical trial . Although participants expressed strong commitments to attend study visits , clinic visit schedules and lengthy waiting times interfered with their multiple obligations as care givers , wage earners , housekeepers , and students . Conclusions The research findings highlight the importance of the social context in shaping participation in HIV prevention trials , beyond focusing solely on individual characteristics . This points to the need to focus interventions to improve visit attendance by promoting a culture of active and engaged participation BACKGROUND Antiretroviral chemoprophylaxis before exposure is a promising approach for the prevention of human immunodeficiency virus ( HIV ) acquisition . METHODS We r and omly assigned 2499 HIV-seronegative men or transgender women who have sex with men to receive a combination of two oral antiretroviral drugs , emtricitabine and tenofovir disoproxil fumarate ( FTC-TDF ) , or placebo once daily . All subjects received HIV testing , risk-reduction counseling , condoms , and management of sexually transmitted infections . RESULTS The study subjects were followed for 3324 person-years ( median , 1.2 years ; maximum , 2.8 years ) . Of these subjects , 10 were found to have been infected with HIV at enrollment , and 100 became infected during follow-up ( 36 in the FTC-TDF group and 64 in the placebo group ) , indicating a 44 % reduction in the incidence of HIV ( 95 % confidence interval , 15 to 63 ; P=0.005 ) . In the FTC-TDF group , the study drug was detected in 22 of 43 of seronegative subjects ( 51 % ) and in 3 of 34 HIV-infected subjects ( 9 % ) ( P<0.001 ) . Nausea was reported more frequently during the first 4 weeks in the FTC-TDF group than in the placebo group ( P<0.001 ) . The two groups had similar rates of serious adverse events ( P=0.57 ) . CONCLUSIONS Oral FTC-TDF provided protection against the acquisition of HIV infection among the subjects . Detectable blood levels strongly correlated with the prophylactic effect . ( Funded by the National Institutes of Health and the Bill and Melinda Gates Foundation ; Clinical Trials.gov number , NCT00458393 . ) There is widespread evidence that male partners influence women ’s ability and willingness to join HIV prevention trials and to use female-controlled prevention strategies such as microbicide gels . VOICE-C was an ancillary study to the Microbicide Trials Network ’s VOICE trial at the Johannesburg site that explored social and structural factors influencing women ’s use of study tablets and vaginal gel . Qualitative data were analyzed from 102 r and omly-selected VOICE participants interviewed through in-depth interviews ( IDI , n = 41 ) ; ethnographic interviews ( n = 21 ) or focus group discussion s ( FGD , n = 40 ) and 22 male partners interviewed in 14 IDI and 2 FGD . Male partners ’ “ underst and ing ” pervaded as a central explanation for how male partners directly and indirectly influenced their female partners ’ trial participation and product use , irrespective of assignment to the gel or tablet study groups . The meaning behind “ underst and ing ” in this context was described by both men and women in two important and complementary ways : ( 1 ) “ comprehension ” of the study purpose including biological properties or effects of the products , and ( 2 ) “ support/agreeability ” for female partners being study participants or using products . During analysis a third dimension of “ underst and ing ” emerged as men ’s acceptance of larger shifts in gender roles and relationship power , and the potential implication s of women ’s increased access to biomedical knowledge , services and prevention methods . Despite displays of some female agency to negotiate and use HIV prevention methods , male partners still have a critical influence on women ’s ability and willingness to do so . Efforts to increase their underst and ing of research goals , study design and products ’ mechanisms of action could ameliorate distrust , empower men to serve as product advocates , adherence buddies , and foster greater adherence support for women in situations where it is needed . Strategies to address gender norms and the broader implication s these have for female-initiated HIV prevention should likewise be integrated into future research and program activities Background An international r and omized clinical trial ( RCT ) on pre-exposure prophylaxis ( PrEP ) as an human immunodeficiency virus (HIV)-prevention intervention found that taken on a daily basis , PrEP was safe and effective among men who have sex with men ( MSM ) and male-to-female transgender women . Within the context of the HIV epidemic in the United States ( US ) , MSM and transgender women are the most appropriate groups to target for PrEP implementation at the population level ; however , their perspectives on evidence d-based biomedical research and the results of this large trial remain virtually unknown . In this study , we examined the acceptability of individual daily use of  PrEP  and assessed potential barriers to community uptake . Methods We conducted semi-structured interviews with an ethnoracially diverse sample of thirty HIV-negative and unknown status MSM ( n = 24 ) and transgender women ( n = 6 ) in three California metropolitan areas . Given the burden of disease among ethnoracial minorities in the US , we purpose fully over sample d for these groups . Thematic coding and analysis of data was conducted utilizing an approach rooted in grounded theory . Results While participants expressed general interest in PrEP availability , results demonstrate : a lack of community awareness and confusion about PrEP ; reservations about PrEP utilization , even when informed of efficacious RCT results ; and concerns regarding equity and the manner in which a PrEP intervention could be packaged and marketed in their communities . Conclusions In order 
    Output:
    
Awareness of PrEP  was low , but once participants were presented with information about PrEP , the majority said they would consider using it .
Concerns about safety , side effects , cost and effectiveness were the most frequently cited barriers to use .
There was little indication of risk compensation .
Healthcare providers would consider prescribing PrEP , but need more information before doing so .
Findings from a rapidly exp and ing evidence base suggest that the majority of population s most likely to benefit from PrEP feel positively towards it .