Phylogenetic Cluster Analysis Identifies Virological and Behavioral Drivers of Human Immunodeficiency Virus Transmission in Men Who Have Sex With Men. (17th April 2020)

• Record Type: Journal Article
• Authors: Bachmann, Nadine; Kusejko, Katharina; Nguyen, Huyen; Chaudron, Sandra E; Kadelka, Claus; Turk, Teja; Böni, Jürg; Perreau, Matthieu; Klimkait, Thomas; Yerly, Sabine; Battegay, Manuel; Rauch, Andri; Ramette, Alban; Vernazza, Pietro; Bernasconi, Enos; Cavassini, Matthias; Günthard, Huldrych F; Kouyos, Roger D
• Is Part Of: Clinical infectious diseases. Volume 72:Number 12(2021)
• Page Start: 2175
• Page End: 2183
• Publication Date: 2020-04-17
• Subjects: phylogenetics -- HIV transmission clusters -- MSM -- drivers of transmission; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciaa411
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract: Background: Identifying local outbreaks and their drivers is a key step toward curbing human immunodeficiency virus (HIV) transmission and potentially achieving HIV elimination. Such outbreaks can be identified as transmission clusters extracted from phylogenetic trees constructed of densely sampled viral sequences. In this study, we combined phylogenetic transmission clusters with extensive data on virological suppression and behavioral risk of cluster members to quantify the drivers of ongoing transmission over 10 years. Methods: Using the comprehensive Swiss HIV Cohort Study and its drug-resistance database, we reconstructed phylogenetic trees for each year between 2007 and 2017. We identified HIV transmission clusters dominated by men who have sex with men (MSM) and determined their annual growth. We used Poisson regression to assess if cluster growth was associated with a per-cluster infectivity and behavioral risk score. Results: Both infectivity and behavioral risk scores were significantly higher in growing MSM transmission clusters compared to nongrowing clusters ( P ≤ .01). The fraction of transmission clusters without infectious members acquiring new infections increased significantly over the study period. The infectivity score was significantly associated with per-capita incidence of MSM transmission clusters in 8 years, while the behavioral risk score was significantly associated with per-capita incidence of MSM transmission clusters in 3 years. Conclusions: We present a phylogenetic method to identify hotspots of ongoing transmission among MSM. Our results demonstrate the effectiveness of treatment as prevention at the population level. However, the significantly increasing number of new infections among transmission clusters without infectious members highlights a relative shift from diagnosed to undiagnosed individuals as drivers of HIV transmission in Swiss MSM. Abstract : By developing a quantitative integrative approach combining phylogenetic, virological, behavioral, and sexually transmitted infection data, we identified changing drivers of ongoing HIV transmission among men who have sex with men enrolled in the Swiss HIV Cohort Study over the last decade, indicating an increasing importance of undiagnosed individuals.