Incremental role of male circumcision on a generalised HIV epidemic through its protective effect against other sexually transmitted infections: from efficacy to effectiveness to population-level impact

Infant Circumcision for Sexually Transmitted Infection Risk Reduction Globally

Population-based studies in high-income countries have failed to find that male circumcision protects against sexually transmitted infections. Using evidence from several sources, we show that male circumcision does protect against HIV during insertive intercourse for men who have sex with men.

Evidence-based circumcision policy for Australia

The aim was (1) to perform an up-to-date systematic review of the male circumcision (MC) literature and (2) to determine the number of adverse medical conditions prevented by early MC in Australia. Searches of PubMed using "circumcision" with 39 keywords and bibliography searches yielded 278 publications meeting our inclusion criteria. Early MC provides immediate and lifetime benefits, including protection against: urinary tract infections, phimosis, inflammatory skin conditions, inferior penile hygiene, candidiasis, various STIs, and penile and prostate cancer. In female partners MC reduces risk of STIs and cervical cancer. A risk-benefit analysis found benefits exceeded procedural risks, which are predominantly minor, by approximately 200 to 1. It was estimated that more than 1 in 2 uncircumcised males will experience an adverse foreskin-related medical condition over their lifetime. An increase in early MC in Australia to mid-1950s prevalence of 85% from the current level of 18.75% would avoid 77,000 cases of infections and other adverse medical conditions over the lifetime for each annual birth cohort. Survey data, physiological measurements, and the anatomical location of penile sensory receptors responsible for sexual sensation indicate that MC has no detrimental effect on sexual function, sensitivity or pleasure. US studies found that early infant MC is cost saving. Evidence-based reviews by the AAP and CDC support early MC as a desirable public health measure. Although MC can be performed at any age, early MC maximizes benefits and minimises procedural risks. Parents should routinely be provided with accurate, up-to-date evidence-based information in an unbiased manner early in a pregnancy so that they have time to weigh benefits and risks of early MC and make an informed decision should they have a son. Parental choice should be respected. A well-trained competent practitioner is essential and local anaesthesia should be routinely used. Third party coverage of costs is advocated.

Critical evaluation of arguments opposing male circumcision: A systematic review

OBJECTIVE

To systematically evaluate evidence against male circumcision (MC).

METHODS

We searched PubMed, Google Scholar, EMBASE and Cochrane databases.

RESULTS

Database searches retrieved 297 publications for inclusion. Bibliographies of these yielded 101 more. After evaluation we found: Claims that MC carries high risk were contradicted by low frequency of adverse events that were virtually all minor and easily treated with complete resolution. Claims that MC causes psychological harm were contradicted by studies finding no such harm. Claims that MC impairs sexual function and pleasure were contradicted by high-quality studies finding no adverse effect. Claims disputing the medical benefits of MC were contradicted by a large body of high-quality evidence indicating protection against a wide range of infections, dermatological conditions, and genital cancers in males and the female sexual partners of men. Risk-benefit analyses reported that benefits exceed risks by 100-200 to 1. To maximize benefits and minimize risks, the evidence supported early infant MC rather than arguments that the procedure should be delayed until males are old enough to decide for themselves. Claims that MC of minors is unethical were contradicted by balanced evaluations of ethical issues supporting the rights of children to be provided with low-risk, high-benefit interventions such as MC for better health. Expert evaluations of case-law supported the legality of MC of minors. Other data demonstrated that early infant MC is cost-saving to health systems.

CONCLUSIONS

Arguments opposing MC are supported mostly by low-quality evidence and opinion, and are contradicted by strong scientific evidence.

Predicting the long-term impact of voluntary medical male circumcision on HIV incidence among men who have sex with men in Beijing, China

Using a deterministic compartmental modeling procedure to fit prevalence from 2005-2015, we projected new HIV cases during 2016-2026 under different coverage rates ranging from 0.0001 (at baseline) to 0.15 (an optimistic assumption) with simulations on varying transmission rates, model calibration to match historical data, and sensitivity analyses for different assumptions. Compared with the baseline (λ = 0.0001), we found the new HIV cases would reduce with the increase of coverage rates of the voluntary medical male circumcision (VMMC) among men who have sex wtih men (MSM). The higher the coverage rate, the lower the new HIV incidence would be. As one of the first studies to model the potential impact of VMMC among MSM in China, our model suggested a modest to the significant public health impact of VMMC. Even at just 15% VMMC annual uptake rate, the reduction in new infections is substantial. Therefore, there is a strong need to determine the efficacy of VMMC among MSM, to improve the evidence base for its potential use among MSM in low circumcision settings. Only then can policymakers decide whether to incorporate VMMC into a package of HIV prevention interventions targeting MSM.

Penile coital injuries in men decline after circumcision: Results from a prospective study of recently circumcised and uncircumcised men in western Kenya

Background

Penile coital injuries are one of the suggested mechanisms behind the increased risk of HIV among uncircumcised men. We evaluated the prevalence and correlates of self-reported penile coital injuries in a longitudinal community-based cohort of young (18–24 years old), newly circumcised and uncircumcised men in Western Kenya.

Methods

Self-reported penile coital injuries were assessed at baseline, 6, 12, 18 and 24 months of follow-up, and were defined as scratches, cuts or abrasions during sex, penile soreness during sex, and skin of the penis bleeding during sex. Associations between penile coital injuries, circumcision, sexual satisfaction, and other covariates were estimated with mixed effect models.

Results

Between November 2008 and April 2010 3,186 participants were enrolled (1,588 into circumcision group and 1,598 as age-matched controls). Among 2,106 (66%) participants sexually active at baseline, 53% reported any penile injury, including 44% scratches, cuts or abrasions; 32% penile pain/soreness; and 22% penile bleeding. In multivariable modeling, risk was lower for circumcised men than uncircumcised men for scratches, cuts and abrasions (aOR = 0.39; 95% CI 0.34–0.44); penile pain/soreness (aOR = 0.58; 95% CI 0.51–0.65), penile bleeding (aOR = 0.53; 95% CI 0.46–0.62), and any penile coital injuries (aOR = 0.47; 95%CI 0.42–0.53). Other significant risk factors included increasing age, history of STIs and genital sores, and multiple sex partners, while condom use was protective. Coital injuries were significantly associated with lower levels of sexual satisfaction in longitudinal analyses (scratches, cuts or abrasions: aOR = 0.87, 95% CI: 0.76–0.98; penile pain/soreness: aOR = 0.82, 95% CI: 0.72–0.93; and penile bleeding: aOR = 0.65, 95% CI: 0.55–0.76).

Conclusions

Self-reported penile coital injuries were common and decreased significantly following circumcision. Improving sexual experience through the removal of a potential source of sexual discomfort may resonate with many men targeted for circumcision services. The role of penile coital injuries in sexual satisfaction, HIV, HSV-2, and as a motivator for seeking circumcision services should be explored further.

Potential impact of multiple interventions on HIV incidence in a hyperendemic region in Western Kenya: a modelling study

BACKGROUND

Multiple prevention interventions, including early antiretroviral therapy initiation, may reduce HIV incidence in hyperendemic settings. Our aim was to predict the short-term impact of various single and combined interventions on HIV spreading in the adult population of Ndhiwa subcounty (Nyanza Province, Kenya).

METHODS

A mathematical model was used with data on adults (15-59 years) from the Ndhiwa HIV Impact in Population Survey to compare the impacts on HIV prevalence, HIV incidence rate, and population viral load suppression of various interventions. These interventions included: improving the cascade of care (use of three guidelines), increasing voluntary medical male circumcision (VMMC), and implementing pre-exposure prophylaxis (PrEP) use among HIV-uninfected women.

RESULTS

After four years, improving separately the cascade of care under the WHO 2013 guidelines and under the treat-all strategy would reduce the overall HIV incidence rate by 46 and 58 %, respectively, vs. the baseline rate, and by 35 and 49 %, respectively, vs. the implementation of the current Kenyan guidelines. With conservative and optimistic scenarios, VMMC and PrEP would reduce the HIV incidence rate by 15-25 % and 22-28 % vs. the baseline, respectively. Combining the WHO 2013 guidelines with VMMC would reduce the HIV incidence rate by 35-56 % and combining the treat-all strategy with VMMC would reduce it by 49-65 %. Combining the WHO 2013 guidelines, VMMC, and PrEP would reduce the HIV incidence rate by 46-67 %.

CONCLUSIONS

The impacts of the WHO 2013 guidelines and the treat-all strategy were relatively close; their implementation is desirable to reduce HIV spread. Combining several strategies is promising in adult populations of hyperendemic areas but requires regular, reliable, and costly monitoring.

Translation of biomedical prevention strategies for HIV: prospects and pitfalls

Early achievements in biomedical approaches for HIV prevention included physical barriers (condoms), clean injection equipment (both for medical use and for injection drug users), blood and blood product safety, and prevention of mother-to-child transmission. In recent years, antiretroviral drugs to reduce the risk of transmission (when the infected person takes the medicines; treatment as prevention) or reduce the risk of acquisition (when the seronegative person takes them; preexposure prophylaxis) have proven to be efficacious. Circumcision of men has also been a major tool relevant for higher prevalence regions such as sub-Saharan Africa. Well-established prevention strategies in the control of sexually transmitted diseases and tuberculosis are highly relevant for HIV (ie, screening, linkage to care, early treatment, and contact tracing). Unfortunately, only slow progress is being made in some available HIV-prevention strategies such as family planning for HIV-infected women who do not want more children and prevention of mother-to-child HIV transmission. Current studies seek to integrate strategies into approaches that combine biomedical, behavioral, and structural methods to achieve prevention synergies. This review identifies the major biomedical approaches demonstrated to be efficacious that are now available. We also highlight the need for behavioral risk reduction and adherence as essential components of any biomedical approach.

Biological basis for the protective effect conferred by male circumcision against HIV infection

Here we provide an up-to-date review of research that explains why uncircumcised men are at higher risk of HIV infection. The inner foreskin is a mucosal epithelium deficient in protective keratin, yet rich in HIV target cells. Soon after sexual exposure to infected mucosal secretions of a HIV-positive partner, infected T-cells from the latter form viral synapses with keratinocytes and transfer HIV to Langerhans cells via dendrites that extend to just under the surface of the inner foreskin. The Langerhans cells with internalized HIV migrate to the basal epidermis and then pass HIV on to T-cells, thus leading to the systemic infection that ensues. Infection is exacerbated in inflammatory states associated with balanoposthitis, the presence of smegma and ulceration - including that caused by infection with herpes simplex virus type 2 and some other sexually transmitted infections (STIs). A high foreskin surface area and tearing of the foreskin or associated frenulum during sexual intercourse also facilitate HIV entry. Thus, by various means, the foreskin is the primary biological weak point that permits HIV infection during heterosexual intercourse. The biological findings could explain why male circumcision protects against HIV infection.

HIV treatment as prevention: considerations in the design, conduct, and analysis of cluster randomized controlled trials of combination HIV prevention

The rigorous evaluation of the impact of combination HIV prevention packages at the population level will be critical for the future of HIV prevention. In this review, we discuss important considerations for the design and interpretation of cluster randomized controlled trials (C-RCTs) of combination prevention interventions. We focus on three large C-RCTs that will start soon and are designed to test the hypothesis that combination prevention packages, including expanded access to antiretroviral therapy, can substantially reduce HIV incidence. Using a general framework to integrate mathematical modelling analysis into the design, conduct, and analysis of C-RCTs will complement traditional statistical analyses and strengthen the evaluation of the interventions. Importantly, even with combination interventions, it may be challenging to substantially reduce HIV incidence over the 2- to 3-y duration of a C-RCT, unless interventions are scaled up rapidly and key populations are reached. Thus, we propose the innovative use of mathematical modelling to conduct interim analyses, when interim HIV incidence data are not available, to allow the ongoing trials to be modified or adapted to reduce the likelihood of inconclusive outcomes. The preplanned, interactive use of mathematical models during C-RCTs will also provide a valuable opportunity to validate and refine model projections.

The future role of rectal and vaginal microbicides to prevent HIV infection in heterosexual populations: implications for product development and prevention

OBJECTIVES

To compare the potential impact of rectal (RMB), vaginal (VMB) and bi-compartment (RVMB) (applied vaginally and protective during vaginal and anal intercourse) microbicides to prevent HIV in various heterosexual populations. To understand when a RMB is as useful than a VMB for women practicing anal intercourse (AI).

METHODS

Mathematical model was used to assess the population-level impact (cumulative fraction of new HIV infections prevented (CFP)) of the three different microbicides in various intervention scenarios and prevalence settings. We derived the break-even RMB efficacy required to reduce a female's cumulative risk of HIV infection by the same amount than a VMB.

RESULTS

Under optimistic coverage (fast roll-out, 100% uptake), a 50% efficacious VMB used in 75% of sex acts in population without AI may prevent ∼33% (27, 42%) new total (men and women combined) HIV infections over 25 years. The 25-year CFP reduces to ∼25% (20, 32%) and 17% (13, 23%) if uptake decreases to 75% and 50%, respectively. Similar loss of impact (by 25%-50%) is observed if the same VMB is introduced in populations with 5%-10% AI and for RR(RAI)=4-20. A RMB is as useful as a VMB (ie, break-even) in populations with 5% AI if RR(RAI)=20 and in populations with 15%-20% AI if RR(RAI)=4, independently of adherence as long as it is the same with both products. The 10-year CFP with a RVMB is twofold larger than for a VMB or RMB when AI=10% and RR(RAI)=10.

CONCLUSIONS

Even low AI frequency can compromise the impact of VMB interventions. RMB and RVMB will be important prevention tools for heterosexual populations.

Will circumcision provide even more protection from HIV to women and men? New estimates of the population impact of circumcision interventions

BACKGROUND

Mathematical modelling has indicated that expansion of male circumcision services in high HIV prevalence settings can substantially reduce population-level HIV transmission. However, these projections need revision to incorporate new data on the effect of male circumcision on the risk of acquiring and transmitting HIV.

METHODS

Recent data on the effect of male circumcision during wound healing and the risk of HIV transmission to women were synthesised based on four trials of circumcision among adults and new observational data of HIV transmission rates in stable partnerships from men circumcised at younger ages. New estimates were generated for the impact of circumcision interventions in two mathematical models, representing the HIV epidemics in Zimbabwe and Kisumu, Kenya. The models did not capture the interaction between circumcision, HIV and other sexually transmitted infections.

RESULTS

An increase in the risk of HIV acquisition and transmission during wound healing is unlikely to have a major impact of circumcision interventions. However, it was estimated that circumcision confers a 46% reduction in the rate of male-to-female HIV transmission. If this reduction begins 2 years after the procedure, the impact of circumcision is substantially enhanced and accelerated compared with previous projections with no such effect-increasing by 40% the infections averted by the intervention overall and doubling the number of infections averted among women.

CONCLUSIONS

Communities, and especially women, may benefit much more from circumcision interventions than had previously been predicted, and these results provide an even greater imperative to increase scale-up of safe male circumcision services.

Male circumcision for HIV prevention in high HIV prevalence settings: what can mathematical modelling contribute to informed decision making?

Experts from UNAIDS, WHO, and the South African Centre for Epidemiological Modelling report their review of mathematical models estimating the impact of male circumcision on HIV incidence in high HIV prevalence settings.