Amplified transmission of HIV-1: comparison of HIV-1 concentrations in semen and blood during acute and chronic infection

Pilcher, Christopher D.; Joaki, George; Hoffman, Irving; Martinson, Francis; Mapanje, Clement; Stewart, Paul W.; Powers, Kimberly A.; Galvin, Shannon; Chilongozi, David; Gama, Syze; Price, Matthew A.; Fiscus, Susan A.; Cohen, Myron S.

doi:10.1097/qad.0b013e3281532c82

Cited by 262 publications

(266 citation statements)

References 25 publications

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“…Using this metric, mean viral load in an Australian cohort undergoing ART over the course of ten years was estimated to be 10 3.3 (Wright et al., 2014). However, mean baseline SPVL was not published in this study and ranges from 10 3.5 to over 10 5 in different populations (Dorrucci, Rezza, Porter, & Phillips, 2007; Fraser et al., 2007; Gras et al., 2009; Mellors et al., 1996; Müller et al., 2009; Pilcher et al., 2007), so an exact measure of ART efficacy in this cohort cannot be inferred. We also note that individuals in marginalized and low‐income populations are more likely to have reduced or inconsistent adherence to ART due to social, economic and psychological barriers (Boyer et al., 2011) and may be less likely to be represented in longitudinal studies of ART efficacy.…”

Section: Methodsmentioning

confidence: 99%

Modelling the evolution of HIV‐1 virulence in response to imperfect therapy and prophylaxis

Mideo

2017

Evolutionary Applications

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Average HIV‐1 virulence appears to have evolved in different directions in different host populations since antiretroviral therapy first became available, and models predict that HIV drugs can select for either higher or lower virulence, depending on how treatment is administered. However, HIV virulence evolution in response to “leaky” therapy (treatment that imperfectly suppresses viral replication) and the use of preventive drugs (pre‐exposure prophylaxis) has not been explored. Using adaptive dynamics, we show that higher virulence can evolve when antiretroviral therapy is imperfectly effective and that this evolution erodes some of the long‐term clinical and epidemiological benefits of HIV treatment. The introduction of pre‐exposure prophylaxis greatly reduces infection prevalence, but can further amplify virulence evolution when it, too, is leaky. Increasing the uptake rate of these imperfect interventions increases selection for higher virulence and can lead to counterintuitive increases in infection prevalence in some scenarios. Although populations almost always fare better with access to interventions than without, untreated individuals could experience particularly poor clinical outcomes when virulence evolves. These findings predict that antiretroviral drugs may have underappreciated evolutionary consequences, but that maximizing drug efficacy can prevent this evolutionary response. We suggest that HIV virulence evolution should be closely monitored as access to interventions continues to improve.

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Section: Methodsmentioning

confidence: 99%

Modelling the evolution of HIV‐1 virulence in response to imperfect therapy and prophylaxis

Mideo

2017

Evolutionary Applications

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“…In addition to being infectious, the undiagnosed population is also more likely to have unprotected sex compared with their diagnosed counterparts [27] and to contain those MSM who are experiencing primary infection (characterized by elevated viraemia [28]). In the UK, while the coverage of HIV testing is 82% among MSM attending sexual health clinics [11], only 55% of HIV-negative MSM reported an HIV test in the last year [29].…”

Section: Discussionmentioning

confidence: 99%

“…In 2010, only 5% of the infectious population met treatment guidelines but were not receiving ART and most of these men went on to start treatment within the next 6 months. While more substantial gains could be achieved through expanding ART to MSM with CD4 counts < 500 cells/mL, an even greater impact could be achieved by halving the undiagnosed population and extending ART to all MSM with a CD4 count < 500 cells/mL.In addition to being infectious, the undiagnosed population is also more likely to have unprotected sex compared with their diagnosed counterparts [27] and to contain those MSM who are experiencing primary infection (characterized by elevated viraemia [28]). In the UK, while the coverage of HIV testing is 82% among MSM attending sexual health clinics [11], only 55% of HIV-negative MSM reported an HIV test in the last year [29].…”

mentioning

confidence: 99%

HIV treatment as prevention among men who have sex with men in the UK: is transmission controlled by universal access to HIV treatment and care?

2013

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ObjectivesIn the UK, free HIV care is provided through dedicated HIV clinics. Using the national cohort of men who have sex with men (MSM) with diagnosed HIV infection and estimates of the number of undiagnosed men, we assessed whether high retention in HIV care and treatment coverage is sufficient to reduce HIV transmission. MethodsAntiretroviral therapy (ART) uptake and viral load distribution among diagnosed men were analysed by treatment status and CD4 count for the period between 2006 and 2010. A multiparameter evidence synthesis (MPES) method was used to estimate the size of the undiagnosed population. The viral load distribution among newly diagnosed untreated men was applied to the undiagnosed population. Infectivity was defined as a viral load > 1500 HIV-1 RNA copies/mL. ResultsBetween 2006 and 2010, ART coverage among all HIV-infected MSM (diagnosed and undiagnosed) increased from 49 to 60%, while the proportion of infectious men fell from 47 to 35%. Over the same period, the number of all HIV-infected MSM increased from 30 000 to 40 100 and the number of infectious MSM remained stable at 14 000. Of the 14 000 infectious MSM in 2010, 62% were undiagnosed, 33% were diagnosed but untreated, and 5% received ART. Extending ART to all diagnosed HIV-infected MSM with CD4 counts < 500 cells/mL in 2010 would have reduced the overall proportion of infectious men from 35 to 29% and halving the proportion who were undiagnosed would further have reduced this to 21%. ConclusionsHigh ART coverage in the UK has reduced the infectivity of the HIV-diagnosed population. However, the effectiveness of treatment as prevention will be limited unless the undiagnosed population is reduced through frequent HIV testing and consistent condom use. IntroductionThe demonstration that prevention of HIV transmission was possible through antiretroviral therapy (ART) was described as 'a defining moment for HIV control' in mid-2011 [1] and the 'breakthrough of the year' for scientific research in December 2011 [2]. ART has been shown to be highly efficacious at preventing transmission from HIVinfected to HIV-negative heterosexual partners, providing that the HIV-positive partner adheres to treatment so that their viral load becomes undetectable [3].While the benefit of HIV treatment for HIV-negative heterosexuals in HIV-serodiscordant relationships has been demonstrated, there is uncertainty surrounding the clinical benefits of 'early' ART (starting ART before the CD4 count reaches 500 cells/mL) for HIV-positive individuals. ORIGINAL RESEARCH 563The START trial [4] is designed to identify the impact of early ART initiation among the HIV-diagnosed population on the development of AIDS-related and non-AIDS-related illnesses. Additional measurable outcomes include adherence, the development of antiretroviral resistance and patient satisfaction. This work will directly inform future national and international treatment policies. However, even if early treatment for the diagnosed HIVpositive population is found to be clinically beneficial,...

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“…There is continued interest in 'scaling-up' HIV prevention among persons most at risk of HIV transmission or MART (West, Corneli, Best, Kurkjian & Cates, 2007). However much of this interest focuses on biological parameters, such as high viral load, which is associated with advanced disease, or acute infection (Pilcher et al, 2007). However, the role of sex workers in the continued spread of HIV infection in southern Africa cannot be over-emphasised.…”

Section: Sex Work In Swazilandmentioning

confidence: 99%

An assessment of sex work in Swaziland: barriers to and opportunities for HIV prevention among sex workers

Chipamaunga

Muula

Mataya

2010

SAHARA-J: Journal of Social Aspects of HIV/AIDS

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The HIV situation in virtually all southern African countries is a generalised epidemic. Despite the fact that almost all adult age and social groups have high HIV prevalence estimates, sex workers are disproportionally affected, with prevalence estimates higher than the general population. In a qualitative study of 61 male and female sex workers in Swaziland, we found that while poverty drove many into sex work, others reported motivations of pleasure or “sensation seeking”, and freedoms from the burden of marriage as perceived benefits of sex work. We also found that penile-vaginal sex was not universal in male-female sexual encounters; and motivation by sex workers for non-condom use included intention to earn more money from unprotected sex, desire for sexual pleasure, and not having time to use condoms. Many sex workers expressed doubts over an alternative lifestyle, even if that change afforded them money to meet their daily necessities. The findings from this study suggest that treating sex workers as a homogenous group that is driven into, or maintain sex work only because of poverty may be problematic, and could hamper HIV-relevant interventions aimed at reducing their vulnerability to sexually transmitted infections.

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Amplified transmission of HIV-1: comparison of HIV-1 concentrations in semen and blood during acute and chronic infection

Cited by 262 publications

References 25 publications

Modelling the evolution of HIV‐1 virulence in response to imperfect therapy and prophylaxis

Modelling the evolution of HIV‐1 virulence in response to imperfect therapy and prophylaxis

HIV treatment as prevention among men who have sex with men in the UK: is transmission controlled by universal access to HIV treatment and care?

An assessment of sex work in Swaziland: barriers to and opportunities for HIV prevention among sex workers

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