HIV Cluster and Outbreak Detection and Response: The Science and Experience

Analysis of HIV transmission characteristics and intervention effects in Guangxi based on molecular networks

OBJECTIVE

This study evaluates changes in HIV transmission and the effectiveness of interventions after two rounds of the Guangxi AIDS Conquering Project (GACP) in Guangxi, China.

METHODS

Samples and epidemiological data from newly diagnosed people with HIV (PWH) between 2014 and 2020 were analyzed. Molecular networks were constructed using nested PCR amplification and sequencing of the pol region, and multivariable logistic regression identified factors associated with clustering and high-degree nodes.

RESULTS

A total of 4227 valid sequences (73.12% inclusion rate) were analyzed. Demographic changes included an increasing proportion of individuals aged at least 50 years (49.66%), with lower education (50.51%), peasants (76.82%), and heterosexual transmission (90.29%). The overall clustering rate was 86.89%, with higher clustering among individuals aged at least 50 years (92.57%), those with primary school or below (89.09%), peasants (88.11%), and CRF08_BC infections (91.48%). Annual declines in cluster growth rate and clustering rates were observed, particularly among individuals aged less than 30 years, college graduates, MSM, and people who inject drugs (PWID). Key transmission hotspots were identified in Lingshan, particularly among older, less-educated individuals, and peasants. Factors associated with clustering included being male (aOR: 1.27), aged at least 50 years (aOR: 3.84), and infected with CRF08_BC (aOR: 2.12). From 2017 to 2020, the risk of clustering and high-degree nodes was lower compared to 2014-2016, suggesting the effectiveness of interventions.

CONCLUSION

Interventions in Guangxi effectively reduced HIV transmission among younger, high-degree populations. However, older, less-educated individuals remain at high risk, necessitating targeted strategies to address their specific needs and achieve better HIV control.

Impact of Disclosing to Patients the Use of Antiretroviral Resistance Testing Results for Molecular HIV Surveillance: A Randomized Experiment in 2 National Surveys

Background

Molecular HIV surveillance (MHS) can be used to help identify and respond to emerging clusters of rapidly spreading HIV transmissions, a practice known as cluster detection and response (CDR). In the United States, MHS relies on HIV gene sequences obtained from routine clinical antiretroviral resistance testing (ARVRT). By law, ARVRT results are reported to public health agencies for MHS and individuals are not asked for their specific consent to do so. This practice has raised ethical concerns, including the lack of consent for, and transparency surrounding, public health uses of these clinical data. Such concerns have spurred debate and could have a chilling effect on the willingness of people living with HIV to agree to ARVRT when recommended clinically and jeopardize the utility of MHS-informed HIV prevention efforts. In response to the lack of routine disclosure of use of ARVRT results for MHS, in 2022, the Presidential Advisory Council on HIV/AIDS (PACHA) issued a resolution calling on the US Centers for Disease Control to "require that providers explain MHS/CDR and the laboratory test results that are collected and used in these surveillance activities to their patients."

Objective

This study aimed to examine the effect of clinician disclosure of the public health uses of ARVRT results for MHS versus clinician nondisclosure on patient willingness to undergo recommended ARVRT.

Methods

We conducted a randomized survey experiment examining the effect of clinician disclosure of the public health uses of ARVRT results for MHS versus clinician nondisclosure (the current standard of care) and subsequent discovery of such uses through a "trusted media source" on patient willingness to undergo recommended ARVRT. Study participants were respondents to 1 of 2 national web-based surveys conducted annually in the United States: the American Men's Internet Survey (AMIS) and the Transgender Women's Internet Survey and Testing (TWIST).

Results

Overall, 4348 AMIS participants (n=2151 disclosure; n=2197 nondisclosure) and 3314 TWIST participants (n=1670 disclosure; n=1644 nondisclosure) completed survey items regarding the randomly assigned vignettes. The majority were willing to undergo ARVRT regardless of which vignette they saw (1670/2151, 82.7% [AMIS] and 1326/1670, 80.8% [TWIST] in the disclosure group; and 1399/2197, 68% [AMIS] and 1101/1674, 68.45% [TWIST] in the nondisclosure group) after later learning about public health uses of ARVRT results.

Conclusions

The majority of respondents expressed willingness to undergo ARVRT even with disclosure of public health uses of these data, but willingness markedly decreased when learning about these uses after the fact, highlighting the importance of transparency in MHS programs. Accordingly, in line with the ethical principle of respect for autonomy and the likelihood that the potential public health benefits of MHS programs will not be compromised, consideration should be given to encouraging clinicians to disclose public health uses of ARVRT at the time ARVRT is recommended.

Minimal Reduction in HIV Transmission Needed for HIV Cluster Detection and Response to be Cost Saving

HIV cluster detection and response (CDR) provides a framework for identifying rapid HIV transmission and guiding implementation of proven HIV prevention and care strategies. Characterizing the relative benefits of CDR is important for guiding policy makers in resource allocation for HIV prevention. We sought to understand how many HIV infections would need to be averted by CDR activities to achieve various return-on-investment (ROI) thresholds. We conducted an ROI analysis of CDR in 2022, incorporating costs and benefits across US jurisdictions funded for HIV surveillance and prevention. Setting ROI thresholds between 1 and 5, we estimated the number of HIV infections that would need to be averted annually by CDR activities to reach ROI thresholds. A scenario was considered cost saving if the ROI > 1. Based on the number of people in national priority molecular clusters and estimated transmission in these clusters, we determined the percent reduction in transmission within these clusters that would be required to achieve the threshold number of HIV infections averted. The number of HIV infections needing to be averted annually ranged from 19 infections (ROI = 1) to 94 infections (ROI = 5). Among 657 HIV transmissions within national priority molecular clusters, the percent reduction in HIV transmission needed to meet ROI thresholds ranged from 2.9% (ROI = 1) to 14.3% (ROI = 5). In conclusion, CDR activities would need to avert a minimal number of HIV infections nationally to achieve cost savings.

Molecular HIV Surveillance: Beyond Cluster Detection and Response

There has been significant controversy surrounding the use of HIV sequence data to identify outbreaks of HIV transmission since the initiation of molecular HIV surveillance (MHS) in the US. The current approach to MHS is comprehensive cluster detection and response (CDR), in which clusters of related infections are identified and used as the basis for cluster-based or population-based interventions. With CDR, there are ethical and stigma concerns around the impingement of individual privacy, as well as legal concerns around the inference of transmission in regions where HIV criminalization laws and statutes exist. Here we propose an alternative approach to the analysis of HIV sequence and public health data that focuses on regions and populations rather than clusters, and still provides useful data for public health agencies.

Phylodynamics for Human Immunodeficiency Virus Prevention: A Miami-Dade County Case Study

BACKGROUND

To date, human immunodeficiency virus (HIV) molecular epidemiology has been primarily used to identify clusters of related infections (cluster detection and response) and then address interventions to these clusters. Community groups have raised concern regarding cluster detection and response related to privacy and ethical concerns. Here we demonstrate how an alternative approach to HIV molecular epidemiology can provide public health benefit.

METHODS

A limited data set for Miami-Dade County provided by the Florida Department of Health was curated and annotated by neighborhood health district (NBHD) and genetic linkage (using a genetic distance threshold of ≤0.5%) and phylodynamic analyses were performed. Phylodynamic analyses were used to infer viral transmissions into Miami-Dade County and between NBHDs within the county.

RESULTS

A total of 7274 HIV sequences from unique persons collected between 1 January 2015 and 31 December 2021 were analyzed, including 50% of the 7894 new diagnoses during this period. The proportion of sequences in local clusters increased over time. Higher ratios of local introductions, compared to viral egress (ie, source of local clusters in other NBHDs) were observed in 3 NBHDs in North Miami (range, 1.9-2.5), suggesting earlier diagnosis, but high numbers of susceptible persons not receiving preexposure prophylaxis. South Dade/Homestead had a low ratio (0.3) of local introductions compared with egress, suggesting later diagnosis and less durable suppression.

CONCLUSIONS

Phylodynamic and genetic linkage analyses can highlight populations and geographic regions that might benefit more from particular types of HIV prevention interventions. These findings will need to be explored by evaluating the impact of scaling up interventions informed by these analyses.

Determinants of HIV-1 transmission clusters and transmitted drug resistance in men who have sex with men: A multicenter study in Portugal (2014-2019)

INTRODUCTION

In the EU/EEA, men who have sex with men (MSM) is a priority group for the prevention and control of HIV-1 infection. In Portugal, the 2023 HIV incidence rate was 8.2 per 100,000 inhabitants, with 876 new infections, 41.7% in MSM. We aim to characterize HIV-1 transmission clusters (TC) and transmitted drug resistance (TDR) and its sociodemographic, behavioral, clinical, and viral genomic determinants in MSM newly diagnosed in Portugal between 2014 and 2019.

METHODS

A total of 340 MSM newly diagnosed with HIV-1 infection at 17 hospitals in Portugal were included. TC was identified with branch support ≥90% and 1.5% genetic distance. Logistic regression models were used to examine factors associated with TC and TDR.

RESULTS

We identified 38 TC with 104 MSM, which includes 81 (26.6%) of the 305 MSM from our sample included in cluster analysis. The overall prevalence of TDR was 8.2%. Only HIV-1 subtype C was significantly associated with TDR. Overall, 10.5% of the clusters had at least 1 surveillance drug resistance mutation. There was no significant difference in the prevalence of TDR or the proportion of Portuguese and migrant MSM inside and outside clusters. Age at diagnosis, district of residence, unprotected sex with a woman, HIV testing, presenter status, and HIV-1 subtype were significantly associated with TC.

CONCLUSION

Specific subgroups of MSM are contributing to HIV-1 clustered transmission in Portugal. However, no association was found between TDR and sociodemographic or behavioral factors. Directed prevention measures should focus on those subgroups.

Perceptions of Molecular HIV Surveillance Among Men Who Have Sex with Men in the United States

Expanding HIV cluster detection using molecular HIV surveillance (MHS) raises ethical and social concerns, which may impede HIV outbreak detection and response as well as deter people living with HIV from seeking care. This underscores the need for effective communication strategies. We examined two methods for explaining MHS among men who have sex with men (MSM) living with HIV and at-risk without HIV in the United States. Participants recruited during the 2021 American Men's Internet Survey (AMIS) were randomized to view a brief video (N = 822) or text (N = 1701) explaining MHS. Respondents with high video engagement were less likely to be concerned about MHS. In the text group, discomfort with MHS decreased as awareness of different public health activities increased. Overall, information about MHS and increased awareness of it improved its acceptability. Effective communication is an essential prerequisite for meaningfully engaging stakeholders regarding MHS implementation in HIV prevention and control efforts.

Benefits of HIV-1 transmission cluster surveillance: a French retrospective observational study of the molecular and epidemiological co-evolution of recent circulating recombinant forms 94 and 132

INTRODUCTION

Molecular surveillance is an important tool for detecting chains of transmission and controlling the HIV epidemic. This can also improve our knowledge of molecular and epidemiological factors for the optimization of prevention. Our objective was to illustrate this by studying the molecular and epidemiological evolution of the cluster including the new circulating recombinant form (CRF) 94_cpx of HIV-1, detected in 2017 and targeted by preventive actions in 2018.

METHODS

In June 2022, 32 HIV-1 sequence databases from French laboratories were screened to identify all individuals who had acquired CRF94_cpx or a similar strain, whatever the date of diagnosis. Phylogenetic analyses were performed with the sequences identified, and biological parameters were collected at the time of diagnosis and after the start of treatment to analyse the evolution of the cluster. Full genomes were sequenced to characterize the new strains.

RESULTS

We analysed 98 HIV-1 isolates: 63 were CRF94, three were unclassifiable, and the other 32 formed a new cluster containing a new recombinant, CRF132_94B, derived from CRF94 and a subtype B strain. At least 95% of the individuals in both the CRF94 and CRF132 clusters were men who have sex with men (MSM), most of whom had acquired HIV less than 12 months before diagnosis. The number of CRF94 diagnoses declined drastically after 2018, but CRF132 strains spread widely between 2020 and 2022, into a different area of Ile-de-France region and within a younger population nevertheless aware of pre-exposure prophylaxis. Higher viraemia, lower CD4 cell counts and delayed treatment efficacy suggested that CRF94 was more virulent than CRF132, possibly due to the F subtype fragment of the vif gene.

CONCLUSIONS

These findings highlight the role of the MSM transmission cluster in spreading HIV and new variants. They show also the benefits of cluster surveillance for improving the targeting of preventive interventions, detecting the emergence of new strains and enriching our knowledge on virulence mechanisms. However, these investigations require support with sufficient resources dedicated to a regional or national programme to be responsive and effective.

Longitudinal Viral Load Clustering for People With HIV Using Functional Principal Component Analysis

Background: Longitudinal measures of viral load (VL) are critical in monitoring the HIV status. While multiple lab indicators exist for monitoring measures of VL, research on clustering historical/longitudinal VL measures is limited. Analyzing longitudinal VL patterns rather than aggregated measures offers deeper insights into HIV status. This study uses functional data clustering to classify longitudinal VL patterns and characterize each cluster by demographics, comorbidities, social behaviors, and CD4 count. Methods: Adult PWH diagnosed from 2005 to 2015 in South Carolina with a 5-year minimum follow-up were included. We compared functional principal component analysis (FPCA), K-means, hierarchical clustering, and Gaussian mixture models for classification and found FPCA yielded the best results. ANOVA was used to compare VL characteristics, demographics, comorbidities, substance uses, and longitudinal CD4 count across clusters. Results: Results obtained from FPCA could best distinguish the characteristics and patterns into four clusters. A total of 5916 PWH were grouped into long-term VS group (Cluster 1, 17.3%), short-term VS group (Cluster 2, 29.8%), suboptimal VS group (Cluster 3, 28.3%), and viral failure group (Cluster 4, 24.9%). In the long-term VS group with an average of 11-year follow-up, PWH displayed sustained VS (95.3%) and lower mean CD4 count (95.3%) than other clusters. The short-term VS group had shorter follow-up (6 years), more comorbidities (31.4%), and lower percentage of time with low CD4 count (79.9%). In suboptimal VS group, PWH were mostly under 30 years old (44.8%) and Black (77.2%), with relatively lower mean VL (92.9%) and lower VR history (18.4%). In the viral failure group, PWH had higher mean VL (40.6%) and lower mean CD4 count (34.7%). Discussion: The findings highlight the impact of continuous clustering in understanding the distinct viral profiles of PWH and emphasize the importance of tailored treatment and insights to target interventions for all PWH.

Profile of Persons Recently Infected with HIV-1 in Belgium: New Insights to Tailor Prevention Efforts

Despite wide availability of prevention and treatment services, including the ongoing roll-out of pre-exposure prophylaxis (PrEP), the HIV epidemic is not under control in Belgium. Hence, there is a recognized need to improve case finding and early diagnosis to curb the further spread of HIV more effectively. The objective of the present study was to improve insight into the profiles of persons recently infected with HIV-1 and on their prevention trajectory. Between May 2018 and December 2022, we selected persons diagnosed in Belgium within three months of the presumed infection date. We then analyzed information collected using a questionnaire covering topics on HIV testing, sexually transmitted infections (STIs), PrEP use, sexual behavior, partner notification and substance use. The data obtained were analyzed alongside information derived from phylogenetic cluster analysis of the viral source of infection. A total of 93 persons with a recent HIV-1 infection completed the questionnaire, the majority (74%) being MSM, 14% were heterosexual women and 12% were heterosexual men. Nearly one-third of participants engaged in sexual activity with an average of 2 to 5 casual partners around the presumed time of infection. A significant percentage reported frequent substance use during sexual activity (65%), being previously diagnosed with STI (65%) and using condoms infrequently (44%). 63% reported a testing frequency of at least one HIV test per year before being diagnosed and 46% notified their previous sex partner(s) after being diagnosed. Over 20% of respondents (including 11 MSM, 4 heterosexual men and 5 heterosexual women) reported exclusive sexual activity with their steady partner. Eight participants (9%, all MSM, 75% born outside of Belgium) reported PrEP use in the past. No significant differences in behavioral characteristics were found between persons who were part of a local transmission cluster (48%) and persons that were not part of a cluster (47%). The study results revealed that the majority of persons diagnosed early with HIV-1 infection in Belgium exhibited characteristics corresponding to a high-at-risk population and were aware of this risk, as evidenced by a high testing frequency. However, partner notification rates were low and use and awareness of PrEP limited. A notable group of persons not corresponding to the high-risk profiles was also identified. This information may help to expose missed opportunities for prevention and contribute to enhancing the implementation of future prevention measures.

Next-Generation Sequencing Methods for Near-Real-Time Molecular Epidemiology of HIV and HCV

The World Health Organisation has set targets of reducing the transmission of new hepatitis C (HCV) infections by 90%, and ending human immunodeficiency virus-1 (HIV) as a public health threat, by 2030. To achieve this, efficient and timely viral surveillance, and effective public health interventions, are required. Traditional epidemiological methods are largely dependent on the recognition of incident cases with symptomatic illness; acute HIV and HCV infections are commonly asymptomatic, which may lead to delays in the recognition of such new infections. Instead, for these viruses, molecular epidemiology may improve the detection of, and response to, clusters of viral transmission. Molecular epidemiology using historical datasets has highlighted key populations that may have benefitted from a timely intervention. Similar analyses performed on contemporary samples are needed to underpin the 2030 targets, but this requires the generation of a cohesive dataset of viral genome sequences in near-real-time. To generate such data, methodologies harnessing next-generation sequencing (NGS) should be utilised. Here we discuss the opportunity presented by NGS for public health surveillance of HIV and HCV, and discuss three methods that can generate sequences for such analysis. These include full-length genome amplification, utilised for analysis of HCV in the research space; tiling PCR, which was the method of choice for many diagnostic laboratories in the SARS-CoV-2 pandemic; and bait-capture hybridisation, which has been utilised in local HIV outbreaks. These techniques could be applied for near-real-time HIV and HCV surveillance, informing public health strategies that will be key to achieving 2030 targets.

Evolving molecular HIV clusters revealed genotype-specific dynamics in Guangzhou, China (2008-2020)

OBJECTIVES

This study investigated the genotype-specific dynamics of molecular HIV clusters (MHCs) in Guangzhou, China, aiming to enhance HIV control.

METHODS

HIV pol sequences from people with HIV (PWH) in Guangzhou (2008-2020) were obtained for genotyping and molecular network creation. MHCs were identified and categorized into three types: emerging, growing, or stable. Clustering rates, proportions of cluster types, and members within each type were calculated and their trends were assessed using joinpoint regression.

RESULTS

Among 8395 PWH, the most prevalent HIV-1 genotypes were CRF07_BC (39.7%) and CRF01_AE (32.6%). The genotype composition has been stable since 2012 (Ps > 0.05). The overall clustering rate was 43.3%, with significant variations across genotypes (P < 0.001), indicating genotype-specific transmission fitness. Significant declines in overall and genotype-specific clustering rates toward the end of 2020 (Ps < 0.05), potentially offer support for HIV control efforts in reducing local infections. The continuously increasing proportions of stable clusters and the gradually decreasing proportions of emerging and growing clusters (either Ps < 0.05 or Ps > 0.05) suggest a trend toward stable molecular network structure. However, growing clusters exhibited CRF55_01B, CRF07_BC, and CRF59_01B dominance that indicate their priority for interventions.

CONCLUSION

The evolving MHCs highlight the genotype-specific cluster dynamics, providing fresh insights for enhanced prevention and control strategies.

User experience with HIV molecular epidemiology in research, surveillance, and cluster detection and response: a needs assessment

OBJECTIVE

HIV molecular epidemiology (HIV ME) is a tool that aims to improve HIV research, surveillance, and cluster detection and response. HIV ME is a core pillar of the U.S. initiative to End the HIV Epidemic but faces some challenges and criticisms from stakeholders. We sought to assess user experience to identify the current needs for HIV ME.

METHODS

Users of HIV ME, including researchers and public health practitioners, were engaged via a structured survey. Needs were assessed via open-ended questions about HIV ME. Data were analyzed using reflexive thematic analysis; the concordance of results was assessed semi-quantitatively.

RESULTS

Of 90 possible HIV-ME end-users, 57 completed the survey (response rate = 63%), which included users engaged in research (n = 29) and public health (n = 28). Respondents identified current imperatives, challenges, and strategies to improve HIV ME. Imperatives included characterization of the virus, identification of HIV hotspots, and tailoring of HIV interventions. Challenges encompassed technological issues, ethical concerns, and implementation difficulties. Strategies to improve HIV ME involved improving data access and analysis, enhancing implementation guidance and resources, and fostering community engagement and support. Researchers and public health practitioners prioritized different imperatives, but similarly emphasized the ethical concerns with HIV ME.

CONCLUSION

The imperatives identified by users underscore the necessity of HIV ME, while the challenges highlight the hurdles to be overcome, including ethical concerns which emerged as a shared emphasis across user groups. The strategies outlined offer a roadmap for overcoming these challenges. These insights, drawn from user experience, present a valuable opportunity to inform the development of guidelines for the ethical application of HIV ME in research, surveillance, and cluster detection and response.

Enhancements to the National HIV Surveillance System, United States, 2013-2023

HIV infection is monitored through the National HIV Surveillance System (NHSS) to help improve the health of people with HIV and reduce transmission. NHSS data are routinely used at federal, state, and local levels to monitor the distribution and transmission of HIV, plan and evaluate prevention and care programs, allocate resources, inform policy development, and identify and respond to rapid transmission in the United States. We describe the expanded use of HIV surveillance data since the 2013 NHSS status update, during which time the Centers for Disease Control and Prevention (CDC) coordinated to revise the HIV surveillance case definition to support the detection of early infection and reporting of laboratory data, expanded data collection to include information on sexual orientation and gender identity, enhanced data deduplication processes to improve quality, and expanded reporting to include social determinants of health and health equity measures. CDC maximized the effects of federal funding by integrating funding for HIV prevention and surveillance into a single program; the integration of program funding has expanded the use of HIV surveillance data and strengthened surveillance, resulting in enhanced cluster response capacity and intensified data-to-care activities to ensure sustained viral suppression. NHSS data serve as the primary source for monitoring HIV trends and progress toward achieving national initiatives, including the US Department of Health and Human Services' Ending the HIV Epidemic in the United States initiative, the White House's National HIV/AIDS Strategy (2022-2025), and Healthy People 2030. The NHSS will continue to modernize, adapt, and broaden its scope as the need for high-quality HIV surveillance data remains.

Integrating HIV Cluster Analysis in Everyday Public Health Practice: Lessons Learned From a Public Health--Academic Partnership

BACKGROUND

The use of molecular HIV cluster analysis to supplement public health contact tracing has shown promise in addressing HIV outbreaks. However, the potential of HIV cluster analysis as an adjunct to daily, person-by-person HIV prevention efforts remains unknown. We documented lessons learned within a unique public health-academic partnership while guiding workaday HIV prevention efforts with near-real-time molecular cluster analysis.

SETTING

A public health-academic partnership in the State of Rhode Island, the United States.

METHODS

We recorded perceptions of our team of academicians and public health practitioners that were encountered in an 18-month study evaluating the integration of molecular cluster analysis with HIV contact tracing for public health benefit. The focus was on monthly conferences where molecular clustering of each new statewide diagnosis was discussed to facilitate targeted interventions and on attempted reinterviews of all newly HIV-diagnosed persons statewide whose HIV sequences clustered to increase partner naming.

RESULTS

Three main themes emerged: First, multidisciplinary conferences are substantially beneficial for gleaning actionable inferences from integrating molecular cluster analysis and public health data. Second, universal reinterviews were perceived to potentially have negative consequences but may be selectively beneficial. Third, the translation of cluster analysis into public health action is hampered by jurisdictional surveillance boundaries and within-jurisdictional data silos, across which data sharing is problematic.

CONCLUSIONS

Insights from a statewide public health-academic partnership support integration of molecular HIV cluster analyses with public health efforts, which can guide public health activities to prevent transmission while identifying substantial barriers to integration, informing continued research.

AUTO-TUNE: selecting the distance threshold for inferring HIV transmission clusters

Molecular surveillance of viral pathogens and inference of transmission networks from genomic data play an increasingly important role in public health efforts, especially for HIV-1. For many methods, the genetic distance threshold used to connect sequences in the transmission network is a key parameter informing the properties of inferred networks. Using a distance threshold that is too high can result in a network with many spurious links, making it difficult to interpret. Conversely, a distance threshold that is too low can result in a network with too few links, which may not capture key insights into clusters of public health concern. Published research using the HIV-TRACE software package frequently uses the default threshold of 0.015 substitutions/site for HIV pol gene sequences, but in many cases, investigators heuristically select other threshold parameters to better capture the underlying dynamics of the epidemic they are studying. Here, we present a general heuristic scoring approach for tuning a distance threshold adaptively, which seeks to prevent the formation of giant clusters. We prioritize the ratio of the sizes of the largest and the second largest cluster, maximizing the number of clusters present in the network. We apply our scoring heuristic to outbreaks with different characteristics, such as regional or temporal variability, and demonstrate the utility of using the scoring mechanism's suggested distance threshold to identify clusters exhibiting risk factors that would have otherwise been more difficult to identify. For example, while we found that a 0.015 substitutions/site distance threshold is typical for US-like epidemics, recent outbreaks like the CRF07_BC subtype among men who have sex with men (MSM) in China have been found to have a lower optimal threshold of 0.005 to better capture the transition from injected drug use (IDU) to MSM as the primary risk factor. Alternatively, in communities surrounding Lake Victoria in Uganda, where there has been sustained heterosexual transmission for many years, we found that a larger distance threshold is necessary to capture a more risk factor-diverse population with sparse sampling over a longer period of time. Such identification may allow for more informed intervention action by respective public health officials.

Health policy counterpublics: Enacting collective resistances to US molecular HIV surveillance and cluster detection and response programs

Health policies and the problems they constitute are deeply shaped by multiple publics. In this article we conceptualize health policy counterpublics: temporally bounded socio-political forms that aim to cultivate particular modes of conduct, generally to resist trajectories set by arms of the state. These counterpublics often emerge from existing social movements and involve varied forms of activism and advocacy. We examine a health policy counterpublic that has arisen in response to new forms of HIV public health surveillance by drawing on public documents and interview data from 2021 with 26 stakeholders who were critical of key policy developments. Since 2018, the national rollout of molecular HIV surveillance (MHS) and cluster detection and response (CDR) programs in the United States has produced sustained controversies among HIV stakeholders, including among organized networks of people living with HIV. This article focuses on how a health policy counterpublic formed around MHS/CDR and how constituents problematized the policy agenda set in motion by federal health agencies, including in relation to data ethics, the meaningful involvement of affected communities, informed consent, the digitization of health systems, and HIV criminalization. Although familiar problems in HIV policymaking, concerns about these issues have been reconfigured in response to the new sociotechnical milieu proffered by MHS/CDR, generating new critical positions aiming to remake public health. Critical attention to the scenes within which health policy controversies play out ought to consider how (counter)publics are made, how problems are constituted, and the broader social movement dynamics and activist resources drawn upon to contest and reimagine policymaking in public life.

Prioritization of ethical concerns regarding HIV molecular epidemiology by public health practitioners and researchers

BACKGROUND

HIV molecular epidemiology (HIV ME) can support the early detection of emerging clusters of new HIV infections by combining HIV sequence data routinely obtained during the clinical treatment of people living with HIV with behavioral, geographic, and sociodemographic information. While information about emerging clusters promises to facilitate HIV prevention and treatment efforts, the use of this data also raises several ethical concerns. We sought to assess how those working on the frontlines of HIV ME, specifically public health practitioners (PHPs) and researchers, prioritized these issues.

METHODS

Ethical issues were identified through literature review, qualitative in-depth interviews, and stakeholder engagement. PHPs and researchers using HIV ME prioritized the issues using best-worst scaling (BWS). A balanced incomplete block design was used to generate 11 choice tasks each consisting of a sub-set of 5 ethical concerns. In each task, respondents were asked to assess the most and least concerning issue. Data were analyzed using conditional logit, with a Swait-Louviere test of poolability. Latent class analysis was then used to explore preference heterogeneity.

RESULTS

In total, 57 respondents completed the BWS experiment May-June 2023 with the Swait-Louviere test indicating that researchers and PHPs could be pooled (p = 0.512). Latent class analysis identified two classes, those highlighting "Harms" (n = 29) (prioritizing concerns about potential risk of legal prosecution, individual harm, and group stigma) and those highlighting "Utility" (n = 28) (prioritizing concerns about limited evidence, resource allocation, non-disclosure of data use for HIV ME, and the potential to infer the directionality of HIV transmission). There were no differences in the characteristics of members across classes.

CONCLUSIONS

The ethical issues of HIV ME vary in importance among stakeholders, reflecting different perspectives on the potential impact and usefulness of the data. Knowing these differences exist can directly inform the focus of future deliberations about the policies and practices of HIV ME in the United States.

Simulation of Full HIV Cluster Networks in a Nationally Representative Model Indicates Intervention Opportunities

BACKGROUND

Clusters of rapid HIV transmission in the United States are increasingly recognized through analysis of HIV molecular sequence data reported to the National HIV Surveillance System. Understanding the full extent of cluster networks is important to assess intervention opportunities. However, full cluster networks include undiagnosed and other infections that cannot be systematically observed in real life.

METHODS

We replicated HIV molecular cluster networks during 2015-2017 in the United States using a stochastic dynamic network simulation model of sexual transmission of HIV. Clusters were defined at the 0.5% genetic distance threshold. Ongoing priority clusters had growth of ≥3 diagnoses/year in multiple years; new priority clusters first had ≥3 diagnoses/year in 2017. We assessed the full extent, composition, and transmission rates of new and ongoing priority clusters.

RESULTS

Full clusters were 3-9 times larger than detected clusters, with median detected cluster sizes in new and ongoing priority clusters of 4 (range 3-9) and 11 (range 3-33), respectively, corresponding to full cluster sizes with a median of 14 (3-74) and 94 (7-318), respectively. A median of 36.3% (range 11.1%-72.6%) of infections in the full new priority clusters were undiagnosed. HIV transmission rates in these clusters were >4 times the overall rate observed in the entire simulation.

CONCLUSIONS

Priority clusters reflect networks with rapid HIV transmission. The substantially larger full extent of these clusters, high proportion of undiagnosed infections, and high transmission rates indicate opportunities for public health intervention and impact.

AUTO-TUNE: SELECTING THE DISTANCE THRESHOLD FOR INFERRING HIV TRANSMISSION CLUSTERS

Molecular surveillance of viral pathogens and inference of transmission networks from genomic data play an increasingly important role in public health efforts, especially for HIV-1. For many methods, the genetic distance threshold used to connect sequences in the transmission network is a key parameter informing the properties of inferred networks. Using a distance threshold that is too high can result in a network with many spurious links, making it difficult to interpret. Conversely, a distance threshold that is too low can result in a network with too few links, which may not capture key insights into clusters of public health concern. Published research using the HIV-TRACE software package frequently uses the default threshold of 0.015 substitutions/site for HIV pol gene sequences, but in many cases, investigators heuristically select other threshold parameters to better capture the underlying dynamics of the epidemic they are studying. Here, we present a general heuristic scoring approach for tuning a distance threshold adaptively, which seeks to prevent the formation of giant clusters. We prioritize the ratio of the sizes of the largest and the second largest cluster, maximizing the number of clusters present in the network. We apply our scoring heuristic to outbreaks with different characteristics, such as regional or temporal variability, and demonstrate the utility of using the scoring mechanism's suggested distance threshold to identify clusters exhibiting risk factors that would have otherwise been more difficult to identify. For example, while we found that a 0.015 substitutions/site distance threshold is typical for US-like epidemics, recent outbreaks like the CRF07_BC subtype among men who have sex with men (MSM) in China have been found to have a lower optimal threshold of 0.005 to better capture the transition from injected drug use (IDU) to MSM as the primary risk factor. Alternatively, in communities surrounding Lake Victoria in Uganda, where there has been sustained hetero-sexual transmission for many years, we found that a larger distance threshold is necessary to capture a more risk factor-diverse population with sparse sampling over a longer period of time. Such identification may allow for more informed intervention action by respective public health officials.

Molecular epidemiology to aid virtual elimination of HIV transmission in Australia

The Global UNAIDS 95/95/95 targets aim to increase the percentage of persons who know their HIV status, receive antiretroviral therapy, and have achieved viral suppression. Achieving these targets requires efforts to improve the public health response to increase access to care for those living with HIV, identify those yet undiagnosed with HIV early, and increase access to prevention for those most at risk of HIV acquisition. HIV infections in Australia are among the lowest globally having recorded significant declines in new diagnoses in the last decade. However, the HIV epidemic has changed with an increasing proportion of newly diagnosed infections among those born outside Australia observed in the last five years. Thus, the current prevention efforts are not enough to achieve the UNAIDS targets and virtual elimination across all population groups. We believe both are possible by including molecular epidemiology in the public health response. Molecular epidemiology methods have been crucial in the field of HIV prevention, particularly in demonstrating the efficacy of treatment as prevention. Cluster detection using molecular epidemiology can provide opportunities for the real-time detection of new outbreaks before they grow, and cluster detection programs are now part of the public health response in the USA and Canada. Here, we review what molecular epidemiology has taught us about HIV evolution and spread. We summarize how we can use this knowledge to improve public health measures by presenting case studies from the USA and Canada. We discuss the successes and challenges of current public health programs in Australia, and how we could use cluster detection as an add-on to identify gaps in current prevention measures easier and respond quicker to growing clusters. Lastly, we raise important ethical and legal challenges that need to be addressed when HIV genotypic data is used in combination with personal data.

Toward Consent in Molecular HIV Surveillance?: Perspectives of Critical Stakeholders

BACKGROUND

The emergence of molecular HIV surveillance (MHS) and cluster detection and response (CDR) programs as key features of the United States (US) HIV strategy since 2018 has caused major controversies. HIV surveillance programs that re-use individuals' routinely collected clinical HIV data do not require consent on the basis that the public benefit of these programs outweighs individuals' rights to opt out. However, criticisms of MHS/CDR have questioned whether expanded uses of HIV genetic sequence data for prevention reach beyond traditional public health ethics frameworks. This study aimed to explore views on consent within MHS/CDR among critical stakeholders.

METHODS

In 2021 we interviewed 26 US HIV stakeholders who identified as being critical or concerned about the rollout of MHS/CDR. Stakeholders included participants belonging to networks of people living with HIV, other advocates, academics, and public health professionals. This analysis focused on identifying the range of positions among critical and concerned stakeholders on consent affordances, opt-outs, how to best inform people living with HIV about how data about them are used in public health programs, and related ethical issues.

RESULTS

Participants were broadly supportive of introducing some forms of consent into MHS/CDR. However, they differed on the specifics of implementing consent. While some participants did not support introducing consent affordances, all supported the idea that people living with HIV should be informed about how HIV surveillance and prevention is conducted and how individuals' data are used.

CONCLUSIONS

MHS/CDR has caused sustained controversy. Among critical stakeholders, consent is generally desirable but contested, although the right for people living with HIV to be informed was centrally supported. In an era of big data-driven public health interventions and routine uses of HIV genetic sequence data in surveillance and prevention, CDC and other agencies should revisit public health ethics frameworks and consider the possibility of consent processes.

Advancing Dialogue About Consent and Molecular HIV Surveillance in the United States: Four Proposals Following a Federal Advisory Panel's Call for Major Reforms

Policy Points Molecular HIV surveillance and cluster detection and response (MHS/CDR) programs have been a core public health activity in the United States since 2018 and are the "fourth pillar" of the Ending the HIV Epidemic initiative launched in 2019. MHS/CDR has caused controversy, including calls for a moratorium from networks of people living with HIV. In October 2022, the Presidential Advisory Council on HIV/AIDS (PACHA) adopted a resolution calling for major reforms. We analyze the policy landscape and present four proposals to federal stakeholders pertaining to PACHA's recommendations about incorporating opt-outs and plain-language notifications into MHS/CDR programs.

Using molecular network analysis to understand current HIV-1 transmission characteristics in an inland area of Yunnan, China

HIV-1 molecular surveillance provides a new approach to explore transmission risks and targeted interventions. From January to June 2021, 663 newly reported HIV-1 cases were recruited in Zhaotong City, Yunnan Province, China. The distribution characteristics of HIV-1 subtypes and HIV-1 molecular network were analysed. Of 542 successfully subtyped samples, 12 HIV-1 strains were identified. The main strains were CRF08_BC (47.0%, 255/542), CRF01_AE (17.0%, 92/542), CRF07_BC (17.0%, 92/542), URFs (8.7%, 47/542), and CRF85_BC (6.5%, 35/542). CRF08_BC was commonly detected among Zhaotong natives, illiterates, and non-farmers and was mostly detected in Zhaoyang County. CRF01_AE was frequently detected among married and homosexual individuals and mostly detected in Weixin and Zhenxiong counties. Among the 516 pol sequences, 187 (36.2%) were clustered. Zhaotong natives, individuals aged ≥60 years, and illiterate individuals were more likely to be found in the network. Assortativity analysis showed that individuals were more likely to be genetically associated when stratified by age, education level, occupation, and reporting area. The genetic diversity of HIV-1 reflects the complexity of local HIV epidemics. Molecular network analyses revealed the subpopulations to focus on and the characteristics of the risk networks. The results will help optimise local prevention and control strategies.

Public Health Response to Clusters of Rapid HIV Transmission Among Hispanic or Latino Gay, Bisexual, and Other Men Who Have Sex with Men - Metropolitan Atlanta, Georgia, 2021-2022

During February 2021-June 2022, the Georgia Department of Public Health (GDPH) detected five clusters of rapid HIV transmission concentrated among Hispanic or Latino (Hispanic) gay, bisexual, and other men who have sex with men (MSM) in metropolitan Atlanta. The clusters were detected through routine analysis of HIV-1 nucleotide sequence data obtained through public health surveillance (1,2). Beginning in spring 2021, GDPH partnered with health districts with jurisdiction in four metropolitan Atlanta counties (Cobb, DeKalb, Fulton, and Gwinnett) and CDC to investigate factors contributing to HIV spread, epidemiologic characteristics, and transmission patterns. Activities included review of surveillance and partner services interview data,† medical chart reviews, and qualitative interviews with service providers and Hispanic MSM community members. By June 2022, these clusters included 75 persons, including 56% who identified as Hispanic, 96% who reported male sex at birth, 81% who reported male-to-male sexual contact, and 84% of whom resided in the four metropolitan Atlanta counties. Qualitative interviews identified barriers to accessing HIV prevention and care services, including language barriers, immigration- and deportation-related concerns, and cultural norms regarding sexuality-related stigma. GDPH and the health districts expanded coordination, initiated culturally concordant HIV prevention marketing and educational activities, developed partnerships with organizations serving Hispanic communities to enhance outreach and services, and obtained funding for a bilingual patient navigation program with academic partners to provide staff members to help persons overcome barriers and understand the health care system. HIV molecular cluster detection can identify rapid HIV transmission among sexual networks involving ethnic and sexual minority groups, draw attention to the needs of affected populations, and advance health equity through tailored responses that address those needs.

Ending the HIV Epidemic: Identifying Barriers and Facilitators to Implement Molecular HIV Surveillance to Develop Real-Time Cluster Detection and Response Interventions for Local Communities

The rapid implementation of molecular HIV surveillance (MHS) has resulted in significant challenges for local health departments to develop real-time cluster detection and response (CDR) interventions for priority populations impacted by HIV. This study is among the first to explore professionals' strategies to implement MHS and develop CDR interventions in real-world public health settings. Methods: Semi-structured qualitative interviews were completed by 21 public health stakeholders in the United States' southern and midwestern regions throughout 2020-2022 to identify themes related to the implementation and development of MHS and CDR. Results for the thematic analysis revealed (1) strengths and limitations in utilizing HIV surveillance data for real-time CDR; (2) limitations of MHS data due to medical provider and staff concerns related to CDR; (3) divergent perspectives on the effectiveness of partner services; (4) optimism, but reluctance about the social network strategy; and (5) enhanced partnerships with community stakeholders to address MHS-related concerns. Conclusions: Enhancing MHS and CDR efforts requires a centralized system for staff to access public health data from multiple databases to develop CDR interventions; designating staff dedicated to CDR interventions; and establishing equitable meaningful partnerships with local community stakeholders to address MHS concerns and develop culturally informed CDR interventions.

Insights into HIV-1 Transmission Dynamics Using Routinely Collected Data in the Mid-Atlantic United States

Background: Molecular epidemiological approaches provide opportunities to characterize HIV transmission dynamics. We analyzed HIV sequences and virus load (VL) results obtained during routine clinical care, and individual’s zip-code location to determine utility of this approach. Methods: HIV-1 pol sequences aligned using ClustalW were subtyped using REGA. A maximum likelihood (ML) tree was generated using IQTree. Transmission clusters with ≤3% genetic distance (GD) and ≥90% bootstrap support were identified using ClusterPicker. We conducted Bayesian analysis using BEAST to confirm transmission clusters. The proportion of nucleotides with ambiguity ≤0.5% was considered indicative of early infection. Descriptive statistics were applied to characterize clusters and group comparisons were performed using chi-square or t-test. Results: Among 2775 adults with data from 2014−2015, 2589 (93%) had subtype B HIV-1, mean age was 44 years (SD 12.7), 66.4% were male, and 25% had nucleotide ambiguity ≤0.5. There were 456 individuals in 193 clusters: 149 dyads, 32 triads, and 12 groups with ≥ four individuals per cluster. More commonly in clusters were males than females, 349 (76.5%) vs. 107 (23.5%), p < 0.0001; younger individuals, 35.3 years (SD 12.1) vs. 44.7 (SD 12.3), p < 0.0001; and those with early HIV-1 infection by nucleotide ambiguity, 202/456 (44.3%) vs. 442/2133 (20.7%), p < 0.0001. Members of 43/193 (22.3%) of clusters included individuals in different jurisdictions. Clusters ≥ four individuals were similarly found using BEAST. HIV-1 viral load (VL) ≥3.0 log10 c/mL was most common among individuals in clusters ≥ four, 18/21, (85.7%) compared to 137/208 (65.8%) in clusters sized 2−3, and 927/1169 (79.3%) who were not in a cluster (p < 0.0001). Discussion: HIV sequence data obtained for HIV clinical management provide insights into regional transmission dynamics. Our findings demonstrate the additional utility of HIV-1 VL data in combination with phylogenetic inferences as an enhanced contact tracing tool to direct HIV treatment and prevention services. Trans-jurisdictional approaches are needed to optimize efforts to end the HIV epidemic.

A stakeholder-driven framework for measuring potential change in the health risks of people who inject drugs (PWID) during the COVID-19 pandemic

BACKGROUND

People who inject drugs (PWID) have likely borne disproportionate health consequences of the COVID-19 pandemic. PWID experienced both interruptions and changes to drug supply and delivery modes of harm reduction, treatment, and other medical services, leading to potentially increased risks for HIV, hepatitis C virus (HCV), and overdose. Given surveillance and research disruptions, proximal, indirect indicators of infectious diseases and overdose should be developed for timely measurement of health effects of the pandemic on PWID.

METHODS

We used group concept mapping and a systems thinking approach to produce an expert stakeholder-generated, multi-level framework for monitoring changes in PWID health outcomes potentially attributable to COVID-19 in the U.S. This socio-ecological measurement framework elucidates proximal and distal contributors to infectious disease and overdose outcomes, many of which can be measured using existing data sources.

RESULTS

The framework includes multi-level components including policy considerations, drug supply/distribution systems, the service delivery landscape, network factors, and individual characteristics such as mental and general health status and service utilization. These components are generally mediated by substance use and sexual behavioral factors to cause changes in incidence of HIV, HCV, sexually transmitted infections, wound/skin infections, and overdose.

CONCLUSION

This measurement framework is intended to increase the quality and timeliness of research on the impacts of COVID-19 in the context of the current pandemic and future crises. Next steps include a ranking process to narrow the drivers of change in health risks to a concise set of indicators that adequately represent framework components, can be written as measurable indicators, and are quantifiable using existing data sources, as well as a publicly available web-based platform for summary data contributions.

Impact of molecular sequence data completeness on HIV cluster detection and a network science approach to enhance detection

Detection of viral transmission clusters using molecular epidemiology is critical to the response pillar of the Ending the HIV Epidemic initiative. Here, we studied whether inference with an incomplete dataset would influence the accuracy of the reconstructed molecular transmission network. We analyzed viral sequence data available from ~ 13,000 individuals with diagnosed HIV (2012-2019) from Houston Health Department surveillance data with 53% completeness (n = 6852 individuals with sequences). We extracted random subsamples and compared the resulting reconstructed networks versus the full-size network. Increasing simulated completeness was associated with an increase in the number of detected clusters. We also subsampled based on the network node influence in the transmission of the virus where we measured Expected Force (ExF) for each node in the network. We simulated the removal of nodes with the highest and then lowest ExF from the full dataset and discovered that 4.7% and 60% of priority clusters were detected respectively. These results highlight the non-uniform impact of capturing high influence nodes in identifying transmission clusters. Although increasing sequence reporting completeness is the way to fully detect HIV transmission patterns, reaching high completeness has remained challenging in the real world. Hence, we suggest taking a network science approach to enhance performance of molecular cluster detection, augmented by node influence information.

An outbreak of HIV infection among people who inject drugs in northeastern Massachusetts: findings and lessons learned from a medical record review

BACKGROUND

We conducted a medical record review for healthcare utilization, risk factors, and clinical data among people who inject drugs (PWID) in Massachusetts to aid HIV outbreak response decision-making and strengthen public health practice.

SETTING

Two large community health centers (CHCs) that provide HIV and related services in northeastern Massachusetts.

METHODS

Between May and July 2018, we reviewed medical records for 88 people with HIV (PWH) connected to the outbreak. The review period included care received from May 1, 2016, through the date of review. Surveillance data were used to establish date of HIV diagnosis and assess viral suppression.

RESULTS

Sixty-nine (78%) people had HIV infection diagnosed during the review period, including 10 acute infections. Persons had a median of 3 primary care visits after HIV diagnosis and zero before diagnosis. During the review period, 72% reported active drug or alcohol use, 62% were prescribed medication assisted treatment, and 41% were prescribed antidepressants. The majority (68, 77%) had a documented ART prescription. HIV viral suppression at < 200 copies/mL was more frequent (73%) than the overall across the State (65%); it did not correlate with any of the sociodemographic characteristics studied in our population. Over half (57%) had been hospitalized at least once during the review period, and 36% had a bacterial infection at hospitalization.

CONCLUSIONS

Medical record review with a field investigation of an outbreak provided data about patterns of health care utilization and comorbidities not available from routine HIV surveillance or case interviews. Integration of HIV screening with treatment for HIV and SUD can strengthen prevention and care services for PWID in northeastern Massachusetts.

Forecasting HIV-1 Genetic Cluster Growth in Illinois,United States

BACKGROUND

HIV intervention activities directed toward both those most likely to transmit and their HIV-negative partners have the potential to substantially disrupt HIV transmission. Using HIV sequence data to construct molecular transmission clusters can reveal individuals whose viruses are connected. The utility of various cluster prioritization schemes measuring cluster growth have been demonstrated using surveillance data in New York City and across the United States, by the Centers for Disease Control and Prevention (CDC).

METHODS

We examined clustering and cluster growth prioritization schemes using Illinois HIV sequence data that include cases from Chicago, a large urban center with high HIV prevalence, to compare their ability to predict future cluster growth.

RESULTS

We found that past cluster growth was a far better predictor of future cluster growth than cluster membership alone but found no substantive difference between the schemes used by CDC and the relative cluster growth scheme previously used in New York City (NYC). Focusing on individuals selected simultaneously by both the CDC and the NYC schemes did not provide additional improvements.

CONCLUSION

Growth-based prioritization schemes can easily be automated in HIV surveillance tools and can be used by health departments to identify and respond to clusters where HIV transmission may be actively occurring.