Molecular epidemiology identifies HIV transmission networks associated with younger age and heterosexual exposure among Korean individuals

Characterization of HIV-1 Transmission Clusters Inferred from the Brazilian Nationwide Genotyping Service Database

The study of HIV-1 transmission networks inferred from viral genetic data can be used to clarify important factors about the dynamics of HIV-1 transmission, such as network growth rate and demographic composition. In Brazil, HIV transmission has been stable since the early 2000s and the study of transmission clusters can provide valuable data to understand the drivers of virus spread. In this work, we analyzed a nation-wide database of approximately 53,000 HIV-1 nucleotide pol sequences sampled from genotyped patients from 2008-2017. Phylogenetic trees were reconstructed for the HIV-1 subtypes B, C and F1 in Brazil and transmission clusters were inferred by applying genetic distances thresholds of 1.5%, 3.0% and 4.5%, as well as high (>0.9) cluster statistical support. An odds ratio test revealed that young men (15-24 years) and individuals with more years of education presented higher odds to cluster. The assortativity coefficient revealed that individuals with similar demographic features tended to cluster together, with emphasis on features, such as place of residence and age. We also observed that assortativity weakens as the genetic distance threshold increases. Our results indicate that the phylogenetic clusters identified here are likely representative of the contact networks that shape HIV transmission, and this is a valuable tool even in sites with low sampling density, such as Brazil.

Molecular network-based intervention brings us closer to ending the HIV pandemic

Precise identification of HIV transmission among populations is a key step in public health responses. However, the HIV transmission network is usually difficult to determine. HIV molecular networks can be determined by phylogenetic approach, genetic distance-based approach, and a combination of both approaches. These approaches are increasingly used to identify transmission networks among populations, reconstruct the history of HIV spread, monitor the dynamics of HIV transmission, guide targeted intervention on key subpopulations, and assess the effects of interventions. Simulation and retrospective studies have demonstrated that these molecular network-based interventions are more cost-effective than random or traditional interventions. However, we still need to address several challenges to improve the practice of molecular network-guided targeting interventions to finally end the HIV epidemic. The data remain limited or difficult to obtain, and more automatic real-time tools are required. In addition, molecular and social networks must be combined, and technical parameters and ethnic issues warrant further studies.

Comparison of the cobas Human Immunodeficiency Virus 1 (HIV-1) Test Using the cobas 4800 System With COBAS AmpliPrep/COBAS TaqMan HIV-1 Test and Abbott RealTime HIV-1 Assay and Performance Evaluation of cobas HIV-1

OBJECTIVES

To compare quantified human immunodeficiency virus type 1 (HIV-1) viral load quantified using the cobas HIV-1 test with that obtained using the CAP/CTM HIV-1 and Abbott RealTime HIV-1 tests and evaluate the performance of cobas HIV-1 using the cobas 4800 system.

METHODS

Clinical samples (n = 123) were quantitatively analyzed using the CAP/CTM HIV-1, Abbott RealTime HIV-1, and cobas HIV-1 tests, and the precision, linearity, and limit of detection of the cobas HIV-1 test were evaluated.

RESULTS

Comparable results were obtained by both methods: ([log CAP/CTM HIV-1 value] = 0.979 * [log cobas HIV-1 test value] + 0.034) and ([log Abbott RealTime HIV-1 value] = 0.985 * [log cobas HIV-1 test value] + 0.027). cobas HIV-1 test results for 89.4% and 93.5% were within 0.5 log10 IU/mL of the CAP/CTM HIV-1 and Abbott RealTime HIV-1 results, respectively.

CONCLUSIONS

The cobas HIV-1 test showed good performance, and its results correlated well with those of other two tests.

Transmission dynamics among participants initiating antiretroviral therapy upon diagnosis of early acute HIV-1 infection in Thailand

OBJECTIVE

To assess transmission characteristics in a predominantly MSM cohort initiating antiretroviral therapy (ART) immediately following diagnosis of acute HIV-1infection (AHI).

METHODS

A longitudinal study (2009-2017) was performed in participants with AHI (n = 439) attending a single clinic in Bangkok. Plasma samples obtained prior to ART were used to obtain HIV-1 pol sequences and combined with clinical and epidemiologic data to assess transmission dynamics (cluster formation and size) using phylogenetic analysis. Clusters were estimated using maximum likelihood, genetic distance of 1.5% and visual inspection. The potential transmitter(s) in a cluster was determined using time to viral suppression and interview data.

RESULTS

The cohort was predominantly MSM (93%) and infected with HIV-1 CRF01_AE (87%). Medians (ranges) for age and viral load prior to ART were 26 (18-70) years and 5.9 (2.5-8.2) log10 HIV-1 RNA copies/ml. Median time from history of HIV-1 exposure to diagnosis was 19 (3-61) days. Viral suppression was observed in 388 of 412 (94%) participants at a median time of 12 weeks following ART. Twenty-six clusters with median cluster size of 2 (2-5) representing 62 of 439 (14%) participants were observed. Younger age was associated with cluster formation: median 28 versus 30 years for unique infections (P = 0.01). A potential transmitter was identified in 11 of 26 (42%) clusters.

CONCLUSION

Despite high rates of viral suppression following diagnosis and treatment of AHI within a cohort of young Thai MSM, HIV-1 transmission continued, reflecting the need to expand awareness and treatment access to the entire MSM population.

At the Nexus: How HIV-Related Immigration Policies Affect Foreign Nationals and Citizens in South Korea

Effective HIV prevention requires the protection and empowerment of marginalized groups at high risk of infection. However, many policies persist that stigmatize these groups and hinder HIV prevention efforts, including HIV-related travel restrictions. In the Republic of Korea, which requires HIV tests for certain visa categories, these restrictions negatively affect the national HIV response and access to accurate information on effective HIV prevention. In addition, they violate migrants' human rights to confidentiality and informed consent to testing and the rights of persons living with HIV (PLHIV) to privacy, work, medical care, bodily integrity, and freedom from discrimination. Furthermore, the discrimination and misconceptions perpetuated by this policy may be driving South Korea's burgeoning infection rates.

Defining HIV-1 transmission clusters based on sequence data

Understanding HIV-1 transmission dynamics is relevant to both screening and intervention strategies of HIV-1 infection. Commonly, HIV-1 transmission chains are determined based on sequence similarity assessed either directly from a sequence alignment or by inferring a phylogenetic tree. This review is aimed at both nonexperts interested in understanding and interpreting studies of HIV-1 transmission, and experts interested in finding the most appropriate cluster definition for a specific dataset and research question. We start by introducing the concepts and methodologies of how HIV-1 transmission clusters usually have been defined. We then present the results of a systematic review of 105 HIV-1 molecular epidemiology studies summarizing the most common methods and definitions in the literature. Finally, we offer our perspectives on how HIV-1 transmission clusters can be defined and provide some guidance based on examples from real life datasets.

Molecular Epidemiology of Human Immunodeficiency Virus

During the evolution of human immunodeficiency virus (HIV), transmissions between humans and primates resulted in multiple HIV lineages in humans. This evolution has been rapid, giving rise to a complex classification and allowing for worldwide spread and intermixing of subtypes, which has consequently led to dozens of circulating recombinant forms. In the Republic of Korea, 12,522 cases of HIV infection have been reported between 1985, when AIDS was first identified, and 2015. This review focuses on the evolution of HIV infection worldwide and the molecular epidemiologic characteristics of HIV in Korea.