Articles tagged as "Sexual transmission"

HIV risk – where do perception and reality overlap?

Editor’s notes: Whereas pregnancy occurs quite frequently after unprotected sex, as discussed in the previous commentary, HIV is not transmitted so easily.  In their guidance on PrEP in 2015, WHO refers to substantial risk at a level of around 3% per year, which of course means that 97% of people in that risk group do not become HIV-positive in that year.  However, risk can only be measured at a group level.  Not only does this mean that there may be unrecognized risk factors, but also at the individual level we seldom calculate a mathematical risk of something happening to us.  So a better understanding of how people perceive their risk and how this relates to their actual likelihood of becoming HIV-positive is important for many aspects of HIV prevention and behaviour change communication.  Among gay men and other men who have sex with men in Europe, Australia and the US, self-identification, combined with a few screening questions could distinguish men at very high risk for whom PrEP is an obvious choice.  Adherence in this group tends to be good and the benefits far outweigh the costs, both financial and other.

In other populations, the equation is not so straightforward.  People at lower risk of HIV may still choose to take PrEP (or use other prevention technologies in the future) but the financial costs of preventing new HIV infections will always be higher for people who adhere less and are at lower risk.  Two papers this month consider aspects of this question.  Haberer et al. considered the overlap between PrEP adherence and risky periods within the Partners Demonstration Project, in Kenya and Uganda.  In this project, serodiscordant couples were recruited and offered PrEP if they met criteria that showed that the seronegative partner had a risk of seroconversion modelled at 3-4% per year.  Thus the seronegative population as a whole was at substantial risk.  The authors then further classified those periods where the HIV-positive participant had not yet had six months of ART and the couple had not used condoms all the time as high risk.  Prevention-effective adherence was defined as taking sufficient PrEP tablets to be effective during the periods when sex could be considered high risk.  The authors found that, reassuringly, during 75% of the time periods in their study, participants should have been protected.  This helps to explain the overall high effectiveness observed in the study and suggests that in this context people make rational decisions about when to adhere to their PrEP and when they do not need to worry so much.

The study contrasts somewhat with a study from South Africa by Maughan-Brown and Venkataramani.  The authors were able to use some of the most detailed information to have been collected on perceived risk of HIV infection among participants in the Cape Area Panel Study which ran from 2002 – 2009.  Detailed questionnaires on risk perception and behaviours were collected in successive surveys.  In the final survey in 2009, HIV testing was included which allowed the authors to test whether perception of risk translated into HIV seroconversion.  Their conclusions are that perception of risk did NOT translate into actual risk.  They acknowledge that perceptions may have changed over the ensuing years but it is a cautionary study that challenges our assumptions that people who consider themselves at risk are the most likely beneficiaries of prevention efforts.  On the other hand, it is impossible to offer prevention technology to people who do not consider themselves at risk.  The challenge is to find communication and delivery systems that will encourage the perfect combination of people who are genuinely at risk, people who want to use the technology and people who will adhere to it faithfully.  A key determinant remains the costs.  Focusing on this perfect combination maximizes the cost-effectiveness of prevention technologies, but that should not preclude allowing people who want to use it to do so at their own cost.

Some potential technologies are still very expensive.  Infusions of broadly neutralizing antibodies are being tested in the Antibody Mediated Prevention (AMP) study in order to define the level and duration of protection of such a strategy.  This will help design future vaccine strategies or could be used for specific protection needs if the cost of antibody production falls.  So, the study from Sok et al. is exciting if still a long way from the field.  Until now, generating broadly neutralizing antibodies in the laboratory has proved challenging.  Standard approaches require multiple sequential immunogens to be administered to drive the antibody maturation process in rabbits or macaques, followed by purification of the relevant monoclonal antibody.  However, cows have a rather different antibody configuration, and in this study, four cows developed useful cross-clade coverage after regular boosts with just a single immunogen.  Of particular interest was the fact that the antibody response continued to evolve so that the later antibodies showed broader activity, despite no additional immunogens.  During the Paris IAS HIV Science conference, Dr Fauci foresaw a future where people living with HIV might be maintained in long-term remission without ART by regular doses of powerful antibodies possibly given subcutaneously.  Science fiction or a realistic avenue?

Finally, we need to remember that some risk factors for HIV transmission are only just being elucidated.  There has been considerable interest in the vaginal microbiome.  Women whose vaginas are largely colonized by lactobacilli are less likely to become HIV-positive, whereas women with bacterial vaginosis, or dysbiosis are more likely to.  Liu et al. have study the microbiome of the foreskin in uncircumcised men in the control arm of one of the large randomized trials of voluntary medical male circumcision in Uganda.  The authors show that men in whom they could demonstrate bacterial species such as prevotella, dialister, finegoldia, and peptoniphilus were significantly more likely to become HIV-positive on follow up than men who did not have these anaerobic microorganisms.  Furthermore, they point out that these same bacteria can be passed on to the woman, where they may also cause colonization and thus transmit an increased susceptibility to the female partner too.  The challenge is that while a simple course of antibiotics may kill the relevant organisms in both men and women, recurrence is common.  Microbiomes are an essential part of sexual and reproductive health.  Another up and coming area for research. 

 

Alignment of adherence and risk for HIV acquisition in a demonstration project of pre-exposure prophylaxis among HIV serodiscordant couples in Kenya and Uganda: a prospective analysis of prevention-effective adherence.

Haberer JE, Kidoguchi L, Heffron R, Mugo N, Bukusi E, Katabira E, Asiimwe S, Thomas KK, Celum C, Baeten JM. J Int AIDS Soc. 2017 Jul 25;20(1):1-9. doi: 10.7448/IAS.20.1.21842.

Introduction: Adherence is essential for pre-exposure prophylaxis (PrEP) to protect against HIV acquisition, but PrEP use need not be life-long. PrEP is most efficient when its use is aligned with periods of risk - a concept termed prevention-effective adherence. The objective of this paper is to describe prevention-effective adherence and predictors of adherence within an open-label delivery project of integrated PrEP and antiretroviral therapy (ART) among HIV serodiscordant couples in Kenya and Uganda (the Partners Demonstration Project).

Methods: We offered PrEP to HIV-uninfected participants until the partner living with HIV had taken ART for ≥6 months (a strategy known as "PrEP as a bridge to ART"). The level of adherence sufficient to protect against HIV was estimated in two ways: ≥4 and ≥6 doses/week (per electronic monitoring). Risk for HIV acquisition was considered high if the couple reported sex with <100% condom use before six months of ART, low if they reported sex but had 100% condom use and/or six months of ART and very low if no sex was reported. We assessed prevention-effective adherence by cross-tabulating PrEP use with HIV risk and used multivariable regression models to assess predictors of ≥4 and ≥6 doses/week.

Results: A total of 985 HIV-uninfected participants initiated PrEP; 67% were male, median age was twenty-nine years, and 67% reported condomless sex in the month before enrolment. An average of ≥4 doses and ≥6 doses/week were taken in 81% and 67% of participant-visits, respectively. Adherence sufficient to protect against HIV acquisition was achieved in 75-88% of participant-visits with high HIV risk. The strongest predictor of achieving sufficient adherence was reporting sex with the study partner who was living with HIV; other statistically significant predictors included no concerns about daily PrEP, pregnancy or pregnancy intention, females aged >25 years, older male partners and desire for relationship success. Predictors of not achieving sufficient adherence were no longer being a couple, delayed PrEP initiation, >6 months of follow-up, ART use >6 months by the partner living with HIV and problem alcohol use.

Conclusions: Over three-quarters of participant-visits by HIV-uninfected partners in serodiscordant couples achieved prevention-effective adherence with PrEP. Greater adherence was observed during months with HIV risk and the strongest predictor of achieving sufficient adherence was sexual activity.

Abstract  Full-text [free] access 

 

Accuracy and determinants of perceived HIV risk among young women in South Africa.

Maughan-Brown B, Venkataramani AS. BMC Public Health. 2017 Jul 21;18(1):42. doi: 10.1186/s12889-017-4593-0.

Background: HIV risk perceptions are a key determinant of HIV testing. The success of efforts to achieve an AIDS-free generation - including reaching the UNAIDS 90-90-90 target - thus depends critically on the content of these perceptions. We examined the accuracy of HIV-risk perceptions and their correlates among young black women in South Africa, a group with one of the highest HIV incidence rates worldwide.

Methods: We used individual-level longitudinal data from the Cape Area Panel Study (CAPS) from 2005 to 2009 on black African women (20-30 years old in 2009) to assess the association between perceived HIV-risk in 2005 and the probability of testing HIV-positive four years later. We then estimated multivariable logistic regressions using cross-sectional data from the 2009 CAPS wave to assess the relationship between risk perceptions and a wide range of demographic, sexual behaviour and psychosocial covariates of perceived HIV-risk.

Results: We found that the proportion testing HIV-positive in 2009 was almost identical across perceived risk categories in 2005 (no, small, moderate, great) (χ 2 = 1.43, p = 0.85). Consistent with epidemiologic risk factors, the likelihood of reporting moderate or great HIV-risk perceptions was associated with condom-use (aOR: 0.57; 95% CI: 0.36, 0.89; p < 0.01); having ≥3 lifetime partners (aOR: 2.38, 95% CI: 1.53, 3.73; p < 0.01); knowledge of one's partner's HIV status (aOR: 0.67; 95% CI: 0.43, 1.07; p = 0.09); and being in an age-disparate partnership (aOR: 1.73; 95% CI: 1.09, 2.76; p = 0.02). However, the likelihood of reporting moderate or great self-perceived risk did not vary with sexually transmitted disease history and respondent age, both strong predictors of HIV risk in the study setting. Risk perceptions were associated with stigmatising attitudes (aOR: 0.53; 95% CI: 0.26, 1.09; p = 0.09); prior HIV testing (aOR: 0.21; 95% CI: 0.13, 0.35; p < 0.01); and having heard that male circumcision is protective (aOR: 0.38; 95% CI: 0.22, 0.64; p < 0.01).

Conclusions: Results indicate that HIV-risk perceptions are inaccurate. Our findings suggest that this inaccuracy stems from HIV-risk perceptions being driven by an incomplete understanding of epidemiological risk and being influenced by a range of psycho-social factors not directly related to sexual behaviour. Consequently, new interventions are needed to align perceived and actual HIV risk.

Abstract  Full-text [free] access 

 

Rapid elicitation of broadly neutralizing antibodies to HIV by immunization in cows.

Sok D, Le KM, Vadnais M, Saye-Francisco KL, Jardine JG, Torres JL, Berndsen ZT, Kong L, Stanfield R, Ruiz J, Ramos A, Liang CH, Chen PL, Criscitiello MF, Mwangi W, Wilson IA, Ward AB, Smider VV, Burton DR. Nature. 2017 Aug 3;548(7665):108-111. doi: 10.1038/nature23301. Epub 2017 Jul 20.

No immunogen to date has reliably elicited broadly neutralizing antibodies to HIV in humans or animal models. Advances in the design of immunogens that antigenically mimic the HIV envelope glycoprotein (Env), such as the soluble cleaved trimer BG505 SOSIP, have improved the elicitation of potent isolate-specific antibody responses in rabbits and macaques, but so far failed to induce broadly neutralizing antibodies. One possible reason for this failure is that the relevant antibody repertoires are poorly suited to target the conserved epitope regions on Env, which are somewhat occluded relative to the exposed variable epitopes. Here, to test this hypothesis, we immunized four cows with BG505 SOSIP. The antibody repertoire of cows contains long third heavy chain complementary determining regions (HCDR3) with an ultralong subset that can reach more than 70 amino acids in length. Remarkably, BG505 SOSIP immunization resulted in rapid elicitation of broad and potent serum antibody responses in all four cows. Longitudinal serum analysis for one cow showed the development of neutralization breadth (20%, n = 117 cross-clade isolates) in 42 days and 96% breadth (n = 117) at 381 days. A monoclonal antibody isolated from this cow harboured an ultralong HCDR3 of 60 amino acids and neutralized 72% of cross-clade isolates (n = 117) with a potent median IC50 of 0.028 μg ml-1. Breadth was elicited with a single trimer immunogen and did not require additional envelope diversity. Immunization of cows may provide an avenue to rapidly generate antibody prophylactics and therapeutics to address disease agents that have evolved to avoid human antibody responses.

Abstract access  

 

Penile anaerobic dysbiosis as a risk factor for HIV infection.

Liu CM, Prodger JL, Tobian AAR, Abraham AG, Kigozi G, Hungate BA, Aziz M, Nalugoda F, Sariya S, Serwadda D, Kaul R, Gray RH, Price LB. MBio. 2017 Jul 25;8(4). pii: e00996-17. doi: 10.1128/mBio.00996-17.

Sexual transmission of HIV requires exposure to the virus and infection of activated mucosal immune cells, specifically CD4+ T cells or dendritic cells. The foreskin is a major site of viral entry in heterosexual transmission of HIV. Although the probability of acquiring HIV from a sexual encounter is low, the risk varies even after adjusting for known HIV risk factors. The genital microbiome may account for some of the variability in risk by interacting with the host immune system to trigger inflammatory responses that mediate the infection of mucosal immune cells. We conducted a case-control study of uncircumcised participants nested within a randomized-controlled trial of male circumcision in Rakai, Uganda. Using penile (coronal sulcus) swabs collected by study personnel at trial enrollment, we characterized the penile microbiome by sequencing and real-time PCR and cytokine levels by electrochemiluminescence assays. The absolute abundances of penile anaerobes at enrollment were associated with later risk of HIV seroconversion, with a 10-fold increase in Prevotella, Dialister, Finegoldia, and Peptoniphilus increasing the odds of HIV acquisition by 54 to 63%, after controlling for other known HIV risk factors. Increased abundances of anaerobic bacteria were also correlated with increased cytokines, including interleukin-8, which can trigger an inflammatory response that recruits susceptible immune cells, suggesting a mechanism underlying the increased risk. These same anaerobic genera can be shared between heterosexual partners and are associated with increased HIV acquisition in women, pointing to anaerobic dysbiosis in the genital microbiome and an accompanying inflammatory response as a novel, independent, and transmissible risk factor for HIV infection.

Importance: We found that uncircumcised men who became infected by HIV during a 2-year clinical trial had higher levels of penile anaerobes than uncircumcised men who remained HIV negative. We also found that having higher levels of penile anaerobes was also associated with higher production of immune factors that recruit HIV target cells to the foreskin, suggesting that anaerobes may modify HIV risk by triggering inflammation. These anaerobes are known to be shared by heterosexual partners and are associated with HIV risk in women. Therefore, penile anaerobes may be a sexually transmissible risk factor for HIV, and modifying the penile microbiome could potentially reduce HIV acquisition in both men and women.

Abstract  Full-text [free] access 

 

 [SC1]Unsure if this matters as they mean the same – but the guidelines literally refer to “substantial risk” which is what you also use in line 8 of the para that follows

Africa
Kenya, South Africa, Uganda
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Age-disparate sexual partnerships - it’s more complicated than sugar daddies and blessers

Editor’s notes: Sugar daddies and blessers are men who provide gifts, money or other benefits to much younger women in exchange for sex.  These relationships are inevitably complex and are often seen as an important mode of transmission for HIV, particularly in Southern and East Africa.  Health education campaigns have raised the issue and aimed to discourage young women from having sex with older men.  However, the research on age-disparate relationships has been harder to interpret. Some studies show that having older partners is not necessarily an independent risk factor for HIV acquisition and others demonstrate a clear age difference in some couples where phylogenetics makes transmission seem very likely.  Nor do all age-disparate relationships involve sugar daddies or blessers.  Many women choose partners who are a few years older than themselves without such clear cut transactional motives.

This month saw Akulian et al. conclude that “age of sexual partner is a major risk factor for HIV acquisition” with frighteningly high rates of HIV incidence of 9.7 per 100 person years occurring among women aged 15-24 years old reporting partnerships with men aged 30-34 years old.  Yet the same research group (Harling et al.), in the same geographic community three years ago, concluded that “partner age disparity did not predict HIV acquisition” and cautioned against using resources for public health campaigns to reduce such partnerships.  A recent paper (de Oliveira et al.) from another research setting, also in KwaZulu-Natal, used phylogenetics to link isolates that were likely to be transmission pairs.  They too found that younger women (aged younger than 25 years) were more likely to have older male partners.  On average in the couples linked by phylogenetics the age difference was 8.7 years when the woman was younger than 25 but only 1.1 years when she was older than 25 years.

This month Schaefer et al. also demonstrated that in the Manicaland cohort in Zimbabwe, where incidence is somewhat lower than in KwaZulu-Natal, young women aged 15-24 years in partnerships with older men were likely to become  HIV positive .  They note that even the introduction of ART has not changed this observed finding, suggesting that the failure to reach men as effectively as we are reaching women, may be a significant reason for ongoing transmission.

The Akullian et al. paper used statistical techniques to smooth the observations from more than 1000 seroconversions observed in more than 25 000 person years of follow-up.  Harling et al. followed the cohort of women aged 15-29 years in the study area and observed 458 seroconversions over 5913 woman years of observation.  Although age-disparate relationships were common, age disparity was not an independent risk factor for HIV infection.  Akullian et al. explain that the real risk is from men aged 25-34 years.  Men in this age group are more likely to have recently acquired HIV, as it is the peak age group for incidence in males.  They are therefore likely to be particularly infectious with higher viral loads. They are also a group that has a low uptake of HIV testing and linkage to ART. 

The rates of ART use and HIV prevalence of older male partners for young women was explored by Evans et al. using data from the South African 2012 National HIV survey.  They found that male partners who were considerably older were more likely to be taking ART and so were likely to transmit fewer infections to their partners, which would tie in well with the Akullian et al. hypothesis of the highest risk being men aged 25-34 years.  The highest incidence is among young women, and these women are most likely to have partners in the 25-34 year old age band.  So we must be careful not to over-generalize.  This helps to explain the apparently differing results from these various studies.  If all age-disparate relationships are included in epidemiological studies, the important impact of transmission from recently infected and untreated 25-34 year old men to their younger female partners aged younger than 25 years may be diluted.

All these studies come from South Africa (usually KwaZulu-Natal) and Zimbabwe and so further detailed epidemiology supported by phylogenetics would be welcome from elsewhere.  Nonetheless, these various studies do translate into a clear message for action.  We need to work hard to find better ways to engage men aged 25-34 years, encourage them to get tested for HIV (see the HIV self-testing approaches above for instance) and link them to care and effective treatment much more efficiently than we are doing at present. 

Sexual partnership age pairings and risk of HIV acquisition in rural South Africa.

Akullian A, Bershteyn A, Klein D, Vandormael A, Bärnighausen T, Tanser F. AIDS. 2017 Jul 31;31(12):1755-1764. doi: 10.1097/QAD.0000000000001553.

Objective: To quantify the contribution of specific sexual partner age groups to the risk of HIV acquisition in men and women in a hyperendemic region of South Africa.

Design: We conducted a population-based cohort study among women (15-49 years of age) and men (15-55 years of age) between 2004 and 2015 in KwaZulu-Natal, South Africa.

Methods: Generalized additive models were used to estimate smoothed HIV incidence rates across partnership age pairings in men and women. Cox proportional hazards regression was used to estimate the relative risk of HIV acquisition by partner age group.

Results: A total of 882 HIV seroconversions were observed in 15  935 person-years for women, incidence rate = 5.5 per 100 person-years [95% confidence interval (CI), 5.2-5.9] and 270 HIV seroconversions were observed in 9372 person-years for men, incidence rate = 2.9 per 100 person-years (95% CI, 2.6-3.2). HIV incidence was highest among 15-24-year-old women reporting partnerships with 30-34-year-old men, incidence rate = 9.7 per 100 person-years (95% CI, 7.2-13.1). Risk of HIV acquisition in women was associated with male partners aged 25-29 years (adjusted hazard ratio; aHR = 1.44, 95% CI, 1.02-2.04) and 30-34 years (aHR = 1.50, 95% CI, 1.08-2.09) relative to male partners aged 35 and above. Risk of HIV acquisition in men was associated with 25-29-year-old (aHR = 1.72, 95% CI, 1.02-2.90) and 30-34-year-old women (aHR = 2.12, 95% CI, 1.03-4.39) compared to partnerships with women aged 15-19 years.

Conclusion: Age of sexual partner is a major risk factor for HIV acquisition in both men and women, independent of one's own age. Partner age pairings play a critical role in driving the cycle of HIV transmission.

Abstract Full-text [free] access

 

Do age-disparate relationships drive HIV incidence in young women? Evidence from a population cohort in rural KwaZulu-Natal, South Africa.

Harling G, Newell ML, Tanser F, Kawachi I, Subramanian SV, Bärnighausen T.J Acquir Immune Defic Syndr. 2014 Aug 1;66(4):443-51. doi: 10.1097/QAI.0000000000000198.

Background: Based on ethnographic investigations and mathematical models, older sexual partners are often considered a major risk factor for HIV for young women in sub-Saharan Africa. Numerous public health campaigns have been conducted to discourage young women from relationships with older men. However, longitudinal evidence relating sex partner age disparity to HIV acquisition in women is limited.

Methods: Using data from a population-based open cohort in rural KwaZulu-Natal, South Africa, we studied 15- to 29-year-old women who were HIV seronegative at first interview between January 2003 and June 2012 (n = 2444). We conducted proportional hazards analysis to establish whether the age disparity of women's most recent sexual partner, updated at each surveillance round, was associated with subsequent HIV acquisition.

Results: A total of 458 HIV seroconversions occurred over 5913 person-years of follow-up (incidence rate: 7.75 per 100 person-years). Age disparate relationships were common in this cohort; 37.7% of women reported a partner 5 or more years older than themselves. The age disparity of women's partners was not associated with HIV acquisition when measured either continuously [hazard ratio (HR) for 1-year increase in partner's age: 1.00, 95% confidence interval (CI): 0.97 to 1.03] or categorically (man ≥5 years older: HR, 0.98; 95% CI: 0.81 to 1.20; man ≥10 years older: HR, 0.98; 95% CI: 0.67 to 1.43). These results were robust to adjustment for known sociodemographic and behavioral HIV risk factors and did not vary significantly by women's age, marital status, education attainment, or household wealth.

Conclusions: HIV incidence in young women was very high in this rural community in KwaZulu-Natal. Partner age disparity did not predict HIV acquistion. Campaigns to reduce age-disparate sexual relationships may not be a cost-effective use of HIV prevention resources in this setting.

Abstract Full-text [free] access

 

Transmission networks and risk of HIV infection in KwaZulu-Natal, South Africa: a community-wide phylogenetic study.

de Oliveira T, Kharsany AB, Gräf T, Cawood C, Khanyile D, Grobler A, Puren A, Madurai S, Baxter C, Karim QA, Karim SS. Lancet HIV. 2017 Jan;4(1):e41-e50. doi: 10.1016/S2352-3018(16)30186-2. Epub 2016 Dec 1.

Background: The incidence of HIV infection in young women in Africa is very high. We did a large-scale community-wide phylogenetic study to examine the underlying HIV transmission dynamics and the source and consequences of high rates of HIV infection in young women in South Africa.

Methods: We did a cross-sectional household survey of randomly selected individuals aged 15-49 years in two neighbouring subdistricts (one urban and one rural) with a high burden of HIV infection in KwaZulu-Natal, South Africa. Participants completed structured questionnaires that captured general demographic, socioeconomic, psychosocial, and behavioural data. Peripheral blood samples were obtained for HIV antibody testing. Samples with HIV RNA viral load greater than 1000 copies per mL were selected for genotyping. We constructed a phylogenetic tree to identify clusters of linked infections (defined as two or more sequences with bootstrap or posterior support ≥90% and genetic distance ≤4·5%).

Findings: From June 11, 2014, to June 22, 2015, we enrolled 9812 participants, 3969 of whom tested HIV positive. HIV prevalence (weighted) was 59·8% in 2835 women aged 25-40 years, 40·3% in 1548 men aged 25-40 years, 22·3% in 2224 women younger than 25 years, and 7·6% in 1472 men younger than 25 years. HIV genotyping was done in 1589 individuals with a viral load of more than 1000 copies per mL. In 90 transmission clusters, 123 women were linked to 103 men. Of 60 possible phylogenetically linked pairings with the 43 women younger than 25 years, 18 (30·0%) probable male partners were younger than 25 years, 37 (61·7%) were aged 25-40 years, and five (8·3%) were aged 41-49 years: mean age difference 8·7 years (95% CI 6·8-10·6; p<0·0001). For the 92 possible phylogenetically linked pairings with the 56 women aged 25-40 years, the age difference dropped to 1·1 years (95% CI -0·6 to 2·8; p=0·111). 16 (39·0%) of 41 probable male partners linked to women younger than 25 years were also linked to women aged 25-40 years. Of 79 men (mean age 31·5 years) linked to women younger than 40 years, 62 (78·5%) were unaware of their HIV-positive status, 76 (96·2%) were not on antiretroviral therapy, and 29 (36·7%) had viral loads of more than 50 000 copies per mL.

Interpretation: Sexual partnering between young women and older men, who might have acquired HIV from women of similar age, is a key feature of the sexual networks driving transmission. Expansion of treatment and combination prevention strategies that include interventions to address age-disparate sexual partnering is crucial to reducing HIV incidence and enabling Africa to reach the goal of ending AIDS as a public health threat.

Abstract access 

 

Age-disparate relationships and HIV incidence in adolescent girls and young women: evidence from Zimbabwe.

Schaefer R, Gregson S, Eaton JW, Mugurungi O, Rhead R, Takaruza A, Maswera R, Nyamukapa C. AIDS. 2017 Jun 19;31(10):1461-1470. doi: 10.1097/QAD.0000000000001506.

Objective: Age-disparate sexual relationships with older men may drive high rates of HIV acquisition in young women in sub-Saharan Africa, but evidence is limited. We investigate the association between age-disparate relationships and HIV incidence in Manicaland, Zimbabwe.

Design: A general-population open-cohort study (six surveys) (1998-2013).

Methods: A total of 3746 young women aged 15-24 years participated in consecutive surveys and were HIV-negative at the beginning of intersurvey periods. Last sexual partner age difference and age-disparate relationships [intergenerational (≥10 years age difference) and intragenerational (5-9 years) versus age-homogeneous (0-4 years)] were tested for associations with HIV incidence in Cox regressions. A proximate determinants framework was used to explore factors possibly explaining variations in the contribution of age-disparate relationships to HIV incidence between populations and over time.

Results: About 126 HIV infections occurred over 8777 person-years (1.43 per 100 person-years; 95% confidence interval = 1.17-1.68). Sixty-five percent of women reported partner age differences of at least 5 years. Increasing partner age differences were associated with higher HIV incidence [adjusted hazard ratio (aHR) = 1.05 (1.01-1.09)]. Intergenerational relationships tended to increase HIV incidence [aHR = 1.78 (0.96-3.29)] but not intragenerational relationships [aHR = 0.91 (0.47-1.76)]. Secondary education was associated with reductions in intergenerational relationships [adjusted odds ratio (aOR) = 0.49 (0.36-0.68)]. Intergenerational relationships were associated with partners having concurrent relationships [aOR = 2.59 (1.81-3.70)], which tended to increase HIV incidence [aHR = 1.74 (0.96-3.17)]. Associations between age disparity and HIV incidence did not change over time.

Conclusion: Sexual relationships with older men expose young women to increased risk of HIV acquisition in Manicaland, which did not change over time, even with introduction of antiretroviral therapy.

Abstract  Full-text [free] access 

 

HIV prevalence and ART use among men in partnerships with 15-29 year old women in South Africa: HIV risk implications for young women in age-disparate partnerships.

Evans M, Maughan-Brown B, Zungu N, George G. AIDS Behav. 2017 Aug;21(8):2533-2542. doi: 10.1007/s10461-017-1741-6.

This study assesses whether men's ART use mitigates HIV-risk within age-disparate partnerships. Using data from the 2012 South African National HIV survey, we analyzed differences in HIV prevalence and ART use between men in age-disparate and age-similar partnerships with young women aged 15-29 using multiple logistic regression analyses. Within partnerships involving women 15-24 years old, men in age-disparate partnerships were more likely to be HIV-positive (5-9 year age-gap: aOR 2.8, 95%CI 1.4-5.2; p < 0.01; 10+ year age-gap: aOR 2.2, 95%CI 1.0-4.6; p < 0.05). Men in age-disparate partnerships who were 5-9 years older were significantly more likely to be HIV-positive and ART-naïve (aOR 2.4, 95%CI 1.2-4.8; p < 0.05), while this was not the case for men 10+ years older (aOR 1.5, 95%CI 0.7-3.6; p = 0.32). No evidence was found that 25-29 year old women were at greater HIV-risk in age-disparate partnerships. Our results indicate that young women aged 15-24 have a greater likelihood of exposure to HIV through age-disparate partnerships, but ART use among men 10+ years older could mitigate risk.

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Africa
South Africa, Zimbabwe
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We still lack good data on many specific populations that are most severely affected by HIV

Editor’s notes: Transgender women are often under-represented in HIV research.  Yet they face many challenges in day to day life with discrimination at many levels.  Employment opportunities are few and many transgender women make a living through sex work.  It is well recognized that they are at specific and increased risks of HIV. Yet many intervention trials group them with gay men and other men who have sex with men, often meaning that the results cannot be disaggregated into more meaningful categories.  The number of transgender women in particular studies is also often too small to make strong conclusions from the data they provide to the study.  So it is encouraging to see Grinsztejn and colleagues establishing a major study specifically in the community of transgender women in Rio de Janeiro, Brazil.  The authors recruited 345 transgender women through a respondent driven sampling process.  This non-random approach is necessitated by the nature of the population, as it would not be possible to make a complete sampling frame from census or other documentation.  However, statistical approaches to make best estimates of population measures are available and the authors found that almost one third of the women were living with HIV and that 29% had not previously been tested for HIV.  The high frequency of other sexually transmitted infections highlights the need for better engagement and services not just for HIV but for their wider sexual and reproductive health and rights needs.

Another population that is under-researched is people with disabilities.  “There is a tribe of Ugandans . . . whose issues and needs have not been given their due and appropriate attention in the fight. By all indications, persons with disabilities have been forgotten, consciously and unconsciously. They represent the forgotten tribe” (Mwesigwa Martin Babu, 2005). Abimanyi-Ochom and colleagues used data collected during the 2011 Ugandan demographic and health survey, which included questions about disabilities for the first time.  While HIV knowledge is similar in those with and without disabilities, people living with disabilities reported indicators of increased risk of acquiring HIV.  Findings included slightly earlier sexual debut and a higher frequency of reported sexually transmitted infections.  Other studies have demonstrated that people living with disabilities may have lower self-esteem and self-efficacy and that abuse, including sexual abuse is more common among this group than among their peers.

The findings are reinforced by a study from Cameroon.  De Beaudrap and colleagues used the same questionnaire that had been used in the Uganda DHS (the Washington short set of questions on disability) to identify people living with disability in a random sample of the population in Yaounde.  The prevalence of HIV was almost twice as high among those with disability than among controls matched by age, sex and residential area.  In line with the discussion in the Ugandan paper, the authors in Cameroon found that women with disability were more likely to receive money for sex and to be victims of sexual violence.  Both of these characteristics were, not surprisingly, associated with still higher rates of HIV infection.  Both papers call for more and better data and we also need to develop and test interventions to reduce the burden of HIV among those living with disabilities.

Unveiling of HIV dynamics among transgender women: a respondent-driven sampling study in Rio de Janeiro, Brazil.

Grinsztejn B, Jalil EM, Monteiro L, Velasque L, Moreira RI, Garcia AC, Castro CV, Krüger A, Luz PM, Liu AY, McFarland W, Buchbinder S, Veloso VG, Wilson EC; Transcender Study Team. Lancet HIV. 2017 Apr;4(4):e169-e176. doi: 10.1016/S2352-3018(17)30015-2. Epub 2017 Feb 8.

Background: The burden of HIV in transgender women (transwomen) in Brazil remains unknown. We aimed to estimate HIV prevalence among transwomen in Rio de Janeiro and to identify predictors of newly diagnosed HIV infections.

Methods: We recruited transwomen from Rio de Janeiro, Brazil, by respondent-driven sampling. Eligibility criteria were self-identification as transwomen, being 18 years of age or older, living in Rio de Janeiro or its metropolitan area, and having a valid peer recruitment coupon. We recruited 12 seed participants from social movements and formative focus groups who then used peer recruitment coupons to refer subsequent peers to the study. We categorised participants as HIV negative, known HIV infected, or newly diagnosed as HIV infected. We assessed predictors of newly diagnosed HIV infections by comparing newly diagnosed with HIV-negative participants. We derived population estimates with the Respondent-Driven Sampling II estimator.

Findings: Between Aug 1, 2015, and Jan 29, 2016, we enrolled 345 eligible transwomen. 29·1% (95% CI 23·2-35·4) of participants had no previous HIV testing (adjusted from 60 participants), 31·2% (18·8-43·6) had HIV infections (adjusted from 141 participants), and 7·0% (0·0-15·9) were newly diagnosed as HIV infected (adjusted from 40 participants). We diagnosed syphilis in 28·9% (18·0-39·8) of participants, rectal chlamydia in 14·6% (5·4-23·8), and gonorrhoea in 13·5% (3·2-23·8). Newly diagnosed HIV infections were associated with black race (odds ratio 22·8 [95% CI 2·9-178·9]; p=0·003), travesti (34·1 [5·8-200·2]; p=0·0001) or transsexual woman (41·3 [6·3-271·2]; p=0·0001) gender identity, history of sex work (30·7 [3·5-267·3]; p=0·002), and history of sniffing cocaine (4·4 [1·4-14·1]; p=0·01).

Interpretation: Our results suggest that transwomen bear the largest burden of HIV among any population at risk in Brazil. The high proportion of HIV diagnosis among young participants points to the need for tailored long-term health-care and prevention services to curb the HIV epidemic and improve the quality of life of transwomen in Brazil.

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HIV/AIDS knowledge, attitudes and behaviour of persons with and without disabilities from the Uganda demographic and health survey 2011: differential access to HIV/AIDS information and services.

Abimanyi-Ochom J, Mannan H, Groce NE, McVeigh J  PLoS One. 2017 Apr 13;12(4):e0174877. doi: 10.1371/journal.pone.0174877. eCollection 2017.

Uganda is among the first to use the Washington Group Short Set of Questions on Disability to identify persons with disabilities in its Demographic and Health Survey. In this paper, we review the HIV knowledge, attitudes and behaviour component of the 2011 Ugandan demographic and health survey, analysing a series of questions comparing those with and without disabilities in relation to HIV/AIDS knowledge, attitudes and practices. We found comparable levels of knowledge on HIV/AIDS for those with and those without disabilities in relation to HIV transmission during delivery (93.89%, 93.26%) and through breastfeeding (89.91%, 90.63%), which may reflect increased attention to reaching the community of persons with disabilities. However, several gaps in the knowledge base of persons with disabilities stood out, including misconceptions of risk of HIV infection through mosquito bites and caring for a relative with HIV in own household (34.39%, 29.86%; p<0.001; 91.53%, 89.00%; p = 0.001, respectively). The issue is not just access to appropriate information but also equitable access to HIV/AIDS services and support. Here we found that persons with multiple disabilities were less likely than individuals without disabilities to return to receive results from their most recent HIV test (0.60[0.41-0.87], p<0.05). HIV testing means little if people do not return for follow-up to know their HIV status and, if necessary, to be connected to available services and supports. Additional findings of note were that persons with disabilities reported having a first sexual encounter at a slightly younger age than peers without disabilities; and persons with disabilities also reported having a sexually transmitted disease (STD) within the last 12 months at significantly higher rates than peers without disabilities (1.38[1.18-1.63], p<0.01), despite reporting comparable knowledge of the need for safer sex practices. This analysis is among the first to use HIV/AIDS-related questions from Demographic Health Surveys to provide information about persons with disabilities in Uganda in comparison to those without disabilities. These findings present a more complex and nuanced understanding of persons with disabilities and HIV/AIDS. If persons with disabilities are becoming sexually active earlier, are more likely to have an STD within the preceding 12 month period and are less likely to receive HIV test results, it is important to understand why. Recommendations are also made for the inclusion of disability measures in Uganda's AIDS Indicator Survey to provide cyclical and systematic data on disability and HIV/AIDS, including HIV prevalence amongst persons with disabilities.

Abstract Full-text [free] access 

Prevalence of HIV infection among people with disabilities: a population-based observational study in Yaoundé, Cameroon (HandiVIH).

De Beaudrap P, Beninguisse G, Pasquier E, Tchoumkeu A, Touko A, Essomba F, Brus A, Aderemi TJ, Hanass-Hancock J, Eide AH, Mac-Seing M, Mont D. Lancet HIV. 2017 Apr;4(4):e161-e168. doi: 10.1016/S2352-3018(16)30209-0. Epub 2017 Jan 24.

Background: In resource-limited settings, people with disabilities have been left behind in the response to HIV. In the HandiVIH study, we estimate and compare HIV prevalence and associated risk factors between people with and without disabilities.

Methods: In this cross-sectional, population-based, observational study, we used two-phase random sampling to recruit adults with disabilities and a control group matched for age, sex, and residential location from households of the general population. We used the Washington Group Short Set of Questions on Disability to identify people with disabilities. We administered an HIV test and a life-course history interview to participants. The primary outcome was the prevalence of HIV among participants with and without disabilities.

Findings: Between Oct 2, 2014, and Nov 30, 2015, we recruited 807 people with disabilities and 807 participants without disabilities from Yaoundé, Cameroon. 28 of 716 people in the control population had a positive HIV test result (crude prevalence 3·9%, 95% CI 2·9-5·3) compared with 50 of 739 people with disabilities (6·8%, 5·0-8·6; conditional odds ratio [OR] 1·7; p=0·04). Women with disabilities were more often involved in paid sexual relationships than were women without disabilities (2·5% vs 0·5%, p=0·05). People with disabilities were also at increased risk of sexual violence than were women without disabilities (11·0% vs 7·5%, OR 1·5; p=0·01). Sexual violence and sex work were strongly associated with increased risk of HIV infection among participants with disabilities but not among controls (OR 3·0, 95% CI 1·6-5·6 for sexual violence and 12·3, 4·4-34·6 for sex work). Analyses were done in men and women.

Interpretation: The higher prevalence of HIV infection in people with disabilities than people without disabilities reflects a higher exposure to HIV infection as well as the presence of disability-associated HIV infection. The susceptibility of people with disabilities to HIV infection seems to be shaped by social and environmental factors. Research is needed to inform firm recommendations on how to protect this vulnerable population.

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Africa, Latin America
Brazil, Cameroon, Uganda
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Violence and sex work in Uganda

Policing the epidemic: high burden of workplace violence among female sex workers in conflict-affected northern Uganda.

Muldoon KA, Akello M, Muzaaya G, Simo A, Shoveller J, Shannon K. Glob Public Health. 2017 Jan;12(1):84-97. Epub 2015 Oct 27.

Sex workers in sub-Saharan Africa experience a high burden of HIV with a paucity of data on violence and links to HIV risk among sex workers, and even less within conflict-affected environments. Data are from a cross-sectional survey of female sex workers in Gulu, northern Uganda (n = 400). Logistic regression was used to determine the specific association between policing and recent physical/sexual violence from clients. A total of 196 (49.0%) sex workers experienced physical/sexual violence by a client. From those who experienced client violence the most common forms included physical assault (58.7%), rape (38.3%), and gang rape (15.8%) Police harassment was very common, a total of 149 (37.3%) reported rushing negotiations with clients because of police presence, a practice that was significantly associated with increased odds of client violence (adjusted odds ratio: 1.61, 95% confidence intervals: 1.03-2.52). Inconsistent condom use with clients, servicing clients in a bar, and working for a manager/pimp were also independently associated with recent client violence. Structural and community-led responses, including decriminalisation, and engagement with police and policy stakeholders, remain critical to addressing violence, both a human rights and public health imperative.

Abstract access  

Editor’s notes: Sex workers are at increased risk of HIV and of violence from multiple perpetrators. There is a paucity of research examining violence among sex workers in conflict-affected areas. Sex work in Uganda is illegal. A police presence can reduce sex workers ability to screen for dangerous clients, negotiate sex acts, price and condom use. This study is from northern Uganda. The site, now at peace, has experienced 20 years of war. A quarter of sex workers are living with HIV. The paper examines the prevalence of client violence, police arrest and other factors, and how they interrelate.

Participants in the study were usually young (median age 21 years), poorly educated and had ≥1 child. One third had been abducted into the Lord’s Resistance Army and two thirds had lived in an Internal Displacement Camp. Some 49% had experienced recent physical or sexual violence from clients.  Eight percent had been gang raped in the past six months. Policing, inconsistent condom use, having sex in a bar and working for a manager or pimp were significantly associated with client violence. Sex workers in this survey face a high prevalence of violence and HIV. Decriminalisation of sex work is vital if sex workers are to access labour and human rights protection and to reduce the high prevalence of violence and HIV

Africa
Uganda
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Negative police activity a structural determinant of HIV

Policing practices as a structural determinant for HIV among sex workers: a systematic review of empirical findings.

Footer KH, Silberzahn BE, Tormohlen KN, Sherman SG. J Int AIDS Soc. 2016 Jul 18;19(4 Suppl 3):20883. doi: 10.7448/IAS.19.4.20883. eCollection 2016.

Introduction: Sex workers are disproportionately infected with HIV worldwide. Significant focus has been placed on understanding the structural determinants of HIV and designing related interventions. Although there is growing international evidence that policing is an important structural HIV determinant among sex workers, the evidence has not been systematically reviewed.

Methods: We conducted a systematic review of quantitative studies to examine the effects of policing on HIV and STI infection and HIV-related outcomes (condom use; syringe use; number of clients; HIV/STI testing and access) among cis and trans women sex workers. Databases included PubMed, Embase, Scopus, Sociological Abstracts, Popline, Global Health (OVID), Web of Science, IBSS, IndMed and WHOLIS. We searched for studies that included police practices as an exposure for HIV or STI infection or HIV-related outcomes.

Results: Of the 137 peer-reviewed articles identified for full text review, 14 were included, representing sex workers' experiences with police across five settings. Arrest was the most commonly explored measure with between 6 and 45% of sex workers reporting having ever been arrested. Sexual coercion was observed between 3 and 37% of the time and police extortion between 12 and 28% across studies. Half the studies used a single measure to capture police behaviours. Studies predominantly focused on "extra-legal policing practices," with insufficient attention to the role of "legal enforcement activities". All studies found an association between police behaviours and HIV or STI infection, or a related risk behaviour.

Conclusions: The review points to a small body of evidence that confirms policing practices as an important structural HIV determinant for sex workers, but studies lack generalizability with respect to identifying those police behaviours most relevant to women's HIV risk environment.

Abstract  Full-text [free] access 

Editor’s notes: The paper reports on a systematic review, which explored how quantitative research to date has operationalized the measurement of law enforcement practices as a structural determinant of HIV for female (including transgender) sex workers. The authors reviewed 14 quantitative studies using policing practices as a micro-structural determinant for HIV risk among sex workers. They found substantial heterogeneity in both the police measures and the health outcomes considered by the different studies. Overall, the studies found that police measures were regularly reported by sex workers, with an average of 34% of sex workers experiencing at least one police measure. They found that arrest was the most commonly explored measure in the studies. Following this, sexual coercion and then police extortion were important.

The studies reported that these police measures were consistently, positively, associated with either HIV infection or STI symptoms or with inconsistent condom use. Having ever been arrested, sexual coercion, police extortion, and syringe confiscation was associated with an increased risk of acquiring an HIV infection or an STI. These measures, and displacement by the police, were also associated with inconsistent condom use. Intervening on interactions between sex workers and the police reduced HIV risk over the time of the programme.

The authors argue that these findings point to the potentially pivotal role that the police have as a structural determinant for HIV in vulnerable populations. However, they argue that nearly all the papers identified in this review fail to take account of the complexities of the risk environment in which law enforcement occurs. The authors thus suggest a need for better measures for legal and extra-legal enforcement practices as mechanisms through which sex workers’ HIV risk is mediated.

Africa, Asia, Europe, Latin America
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Couples talking about prevention and supporting each other on PrEP and ART: lessons from Kenya

I knew I would be safer. Experiences of Kenyan HIV serodiscordant couples soon after pre-exposure prophylaxis (PrEP) initiation.

Ngure K, Heffron R, Curran K, Vusha S, Ngutu M, Mugo N, Celum C, Baeten JM. AIDS Patient Care STDS. 2016 Feb;30(2):78-83. doi: 10.1089/apc.2015.0259.

Pre-exposure prophylaxis (PrEP) for HIV-uninfected persons is highly efficacious for HIV prevention. Understanding how people at risk for HIV will use PrEP is important to inform PrEP scale-up and implementation. We used qualitative methods to gather insights into couples' early experiences with PrEP use within the Partners Demonstration Project, an open-label implementation study evaluating integrated delivery of PrEP and antiretroviral therapy (ART). PrEP is offered to HIV uninfected partners until the HIV-infected partner initiates and sustains ART use (i.e., PrEP as a "bridge" to ART initiation and viral suppression). From August 2013 to March 2014 we conducted 20 in-depth dyadic interviews (n = 40) with heterosexual HIV serodiscordant couples participating at the Thika, Kenya study site, exploring how couples make decisions about using PrEP for HIV prevention. We developed and applied deductive and inductive codes to identify key themes related to experiences of PrEP initiation and use of time-limited PrEP. Couples reported that PrEP offered them an additional strategy to reduce the risk of HIV transmission, meet their fertility desires, and cope with HIV serodiscordance. Remaining HIV negative at follow-up visits reinforced couples' decisions and motivated continued adherence to PrEP. In addition, confidence in their provider's advice and client-friendly services were critical to their decisions to initiate and continue use of PrEP. Strategies for wide-scale PrEP delivery for HIV serodiscordant couples in low resource settings may include building capacity of health providers to counsel on PrEP adoption while addressing couples' concerns and barriers to adoption and continued use.

Abstract access

Editor’s notes: This paper is based on findings from the Partners Demonstration Project. This project evaluated the implementation of ART and PrEP for HIV-1 prevention in African heterosexual HIV-1 serodiscordant couples in Uganda and Kenya. As has been reported elsewhere, the research achieved impressive reductions in HIV-incidence. The strategy adopted in the project was to provide PrEP to the HIV-negative partner until the HIV-positive partner had sustained their use of ART for six months. Using data from Kenya, the authors describe in this paper the value placed by couples on PrEP, which underpinned the study success. Couples wanted to use PrEP because PrEP (and ART) provided the possibility of reduced HIV transmission. In addition to the findings on reasons for PrEP use, this paper also offers insights into couple dynamics. The research was conducted with mutually disclosed HIV serodiscordant couples. The authors illustrated through their analysis and the excerpts from interviews used in the text, the importance of communication between partners. They also, importantly, illustrate differences between couples. The authors describe the use of both verbal and non-verbal communication in discussions about PrEP and ART. Through the data in this paper a picture is built up on the importance of open and frank communication in decisions about using and sustaining the use of PrEP and ART. In a study setting, couples could be afforded support which might be scarce in public health settings. Even so, the findings underline the value of being sensitive to context and individual needs, in supporting PrEP and ART roll-out.

Africa
Kenya
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Tenofovir vaginal gel offers significant protection against HSV-2 infection

Tenofovir gel for the prevention of herpes simplex virus type 2 infection.

Abdool Karim SS, Abdool Karim Q, Kharsany AB, Baxter C, Grobler AC, Werner L, Kashuba A, Mansoor LE, Samsunder N, Mindel A, Gengiah TN, Group CT. N Engl J Med. 2015 Aug 6;373(6):530-9. doi: 10.1056/NEJMoa1410649.

Background: Globally, herpes simplex virus type 2 (HSV-2) infection is the most common cause of genital ulcer disease. Effective prevention strategies for HSV-2 infection are needed to achieve the goals of the World Health Organization global strategy for the prevention and control of sexually transmitted infections.

Methods: We assessed the effectiveness of pericoital tenofovir gel, an antiviral microbicide, in preventing HSV-2 acquisition in a subgroup of 422 HSV-2-negative women enrolled in the Centre for the AIDS Programme of Research in South Africa (CAPRISA) 004 study, a double-blind, randomized, placebo-controlled trial. Incident HSV-2 cases were identified by evidence of seroconversion on an HSV-2 IgG enzyme-linked immunosorbent assay between study enrollment and exit. A confirmatory analysis was performed by Western blot testing.

Results: The HSV-2 incidence rate was 10.2 cases per 100 person-years (95% confidence interval [CI], 6.8 to 14.7) among 202 women assigned to tenofovir gel, as compared with 21.0 cases per 100 person-years (95% CI, 16.0 to 27.2) among 222 women assigned to placebo gel (incidence rate ratio, 0.49; 95% CI, 0.30 to 0.77; P=0.003). The HSV-2 incidence rate among the 25 women with vaginal tenofovir concentrations of 10 000 ng per milliliter or more was 5.7 cases per 100 person-years, as compared with 15.5 cases per 100 person-years among the 103 women with no detectable vaginal tenofovir (incidence rate ratio, 0.37; 95% CI, 0.04 to 1.51; P=0.14). As confirmed by Western blot testing, there were 16 HSV-2 seroconversions among women assigned to tenofovir gel as compared with 36 among those assigned to the placebo gel (incidence rate ratio, 0.45; 95% CI, 0.23 to 0.82; P=0.005).

Conclusions: In this study in South Africa, pericoital application of tenofovir gel reduced HSV-2 acquisition in women.

Abstract access 

Editor’s notes: Oral tenofovir is widely used to prevent and treat HIV infection, but application of a topical tenofovir vaginal-gel formulation has not been found to be protective against HIV, likely because of low rates of adherence. In contrast, analyses of tenofovir gel protection against HSV-2, herpes simplex virus, has showed some promise. This paper presents additional data and analyses from the CAPRISA004 study which found the modest effect of protection against HIV, but significant protection against HSV-2 (51% effectiveness). A sub-analysis confirmed that those people with higher vaginal tenofovir concentrations were almost three times less likely to acquire the herpes virus than those people with no detectable drug concentration. In the absence of an effective vaccine or cure for HSV-2 infection, pericoital tenofovir gel has the potential to increase the options for HSV-2 prevention, and have an indirect effect on HIV infection. 

Africa
South Africa
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