How Does Voluntary Medical Male Circumcision Reduce HIV Risk?

Preventing Behavioral Human Immunodeficiency Virus Infections in Adolescents and Young Adults

HIV prevention in adolescents and young adults (AYA) requires a multi-pronged strategy encompassing behavioral, biologic, and structural approaches. This article reviews the epidemiology of HIV infection in the United States and its pathogenesis and transmission. Prevention approaches are discussed in more detail, with an emphasis on how each approach is relevant to AYA populations. Information is summarized in a resource table with links to references and in-depth discussions of the topics reviewed in this article.

Penile microbiome: decoding its impact on HIV risk

PURPOSE OF REVIEW

The penile microbiome has been linked to local inflammation and increased risk for sexually transmitted infections, including HIV. This review explores recent studies of this emerging area of HIV research.

RECENT FINDINGS

The male urogenital tract supports multiple distinct niches, where their associated microbiome are shaped by abiotic (e.g., oxygen, moisture) and biotic (e.g., host immunity) environmental factors and host behaviors, particularly sexual activity. In addition, male circumcision is a significant drivers of male genital microbiome in both children and adults. Recent sexual partner studies provide new insight into the exchange of genital bacteria and concurrent local immune changes that may impact HIV risk.

SUMMARY

The male genital microbiome is shaped by the local microenvironment and host behaviors including sexual activity. Improving our understanding of the connection between the male genital microbiome, local inflammation, and HIV susceptibility, as well as how pro-inflammatory genital bacteria are transmitted between sexual partners may inform new strategies to prevent HIV transmission.

Effect of cryopreservation on CD4+ T cell subsets in foreskin tissue

Voluntary medical male circumcision (VMMC) reduces HIV acquisition by at least 60%, but the determinants of HIV susceptibility in foreskin tissues are incompletely understood. Flow cytometry is a powerful tool that helps us understand tissue immune defenses in mucosal tissue like the inner foreskin, but foreskin flow cytometry has only been validated using fresh tissue samples. This restricts immune analyses to timepoints immediately after surgical acquisition and hinders research in this area. We compared fresh analysis with whole tissue cryopreservation and later thawing and digestion to analyze CD4+ T cell populations relevant to HIV susceptibility (CCR5, CD25, CD127, CCR4, CXCR3, CCR6, CCR10, HLA-DR, and CD38). Eight foreskin samples from HIV-negative males aged >18 years were collected after VMMC. For each sample, half the foreskin was immediately cryopreserved for later digestion and flow cytometry analysis, while the remaining tissues were analyzed fresh. We demonstrate no significant impact of cryopreservation on CD4+ T cell expression of CD25, CCR4, CCR6, HLA-DR, CCR10, or CD127. Although expression levels of CCR5, CD38, and CXCR3 were increased after cryopreservation, the relative ranking of participants was retained. In conclusion, cryopreserved foreskin tissues may be suitable for subsequent digestion and flow cytometry phenotyping of HIV-susceptible T cell populations.

Male circumcision uptake and misperceived norms about male circumcision: Cross-sectional, population-based study in rural Uganda

Background

Over the past decade, 15 high-priority countries in eastern and southern Africa have promoted voluntary medical male circumcision for human immunodeficiency virus (HIV) and sexually transmitted infection (STI) prevention. The prevalence of male circumcision in Uganda nearly doubled from 26% in 2011 to 43% in 2016, but remains below the 2020 target level. Little is known about how common male circumcision is perceived to be, how accurate such perceptions are, and whether they are associated with men's own circumcision uptake.

Methods

We conducted a cross-sectional study of all adult residents of eight villages in Rwampara District, southwestern Uganda in 2020-2022. We elicited their perceptions of the adult male circumcision prevalence within their village: >50% (most men), 10% to <50% (some), <10%, (few to none), or do not know. We compared their perceived norms to the aggregated prevalence of circumcision reported in these villages. We used a modified multivariable Poisson regression model to estimate the association between perceived norms and personal circumcision uptake among men.

Results

We surveyed 1566 participants (91% response rate): 698 men and 868 women. Among the men, 167 (27%) reported being circumcised, including 167/444 (38%) men <50 years of age. Approximately one-fourth of the population (189 (27%) men and 177 (20%) women) believed that few to no men in their own village had been circumcised. In a multivariable regression model, men who underestimated the prevalence of male circumcision were less likely to be circumcised themselves (adjusted relative risk (aRR) = 0.51; 95% confidence interval (CI) = 0.37-0.83).

Conclusions

In this population-based study in rural Uganda, one-fourth of men underestimated the prevalence of male circumcision. Men who underestimated the extent of circumcision uptake were themselves less likely to be circumcised. If the observed association is causal and underestimates within the population contribute to low uptake, then interventions correcting these misperceived norms could increase uptake of voluntary medical male circumcision.

HIV infection

The AIDS epidemic has been a global public health issue for more than 40 years and has resulted in ~40 million deaths. AIDS is caused by the retrovirus, HIV-1, which is transmitted via body fluids and secretions. After infection, the virus invades host cells by attaching to CD4 receptors and thereafter one of two major chemokine coreceptors, CCR5 or CXCR4, destroying the host cell, most often a T lymphocyte, as it replicates. If unchecked this can lead to an immune-deficient state and demise over a period of ~2-10 years. The discovery and global roll-out of rapid diagnostics and effective antiretroviral therapy led to a large reduction in mortality and morbidity and to an expanding group of individuals requiring lifelong viral suppressive therapy. Viral suppression eliminates sexual transmission of the virus and greatly improves health outcomes. HIV infection, although still stigmatized, is now a chronic and manageable condition. Ultimate epidemic control will require prevention and treatment to be made available, affordable and accessible for all. Furthermore, the focus should be heavily oriented towards long-term well-being, care for multimorbidity and good quality of life. Intense research efforts continue for therapeutic and/or preventive vaccines, novel immunotherapies and a cure.

Voluntary Medical Male Circumcision to Reduce HIV Acquisition and Transmission

PURPOSE OF REVIEW

This commentary introduces the special Global Health Section on the state of voluntary medical male circumcision (VMMC) programs and current knowledge as to role of VMMC prevention of HIV infection acquisition in men and, indirectly, women.

RECENT FINDINGS

Since the first clinical trial of VMMC in Africa was published in 2005, implementation of programs has depended on illuminating best practices and key obstacles in the effort to expand VMMC in areas of high HIV prevalence to reduce HIV acquisition among men, with consequent benefits that uninfected men will not infect others. Global efforts are focused on sub-Saharan Africa, given the favorable expected impact of VMMC deployment where HIV incidence is high and circumcision rates are low. With estimated field effectiveness estimated to exceed 60%, reduced HIV risk for circumcised men in sub-Saharan Africa based on a once-only minor surgical intervention provides extraordinary preventive benefits. Where high VMMC rates have been achieved, declining HIV incidence rates may be partially or substantially attributed to VMMC, but this remains to be investigated. Articles in this special section address achievements, obstacles and risks, and plans for future progress in partnership with affected communities.