Objectives Subtypes A1 and B are the most prevalent HIV-1 clades in Greece. Subtype A1 epidemic is highly monophyletic and corresponds to transmissions that occurred locally. Our aim in this molecular epidemiology analysis was to investigate the role of early treatment in preventing new HIV-1 transmissions.
Methods Our analysis focused on 791 subtype A1 sequences from treatment-naïve individuals in Greece. Estimation of infection dates was performed by molecular clock calculations using Bayesian methods. We estimated the time interval between (1) the infection and sampling dates (linkage to care window), (2) the sampling dates and antiretroviral therapy (ART) initiation (treatment window), and (3) the infection dates and ART initiation (transmissibility window) for the study population. We also inferred the putative source of HIV infections between individuals of different groups divided according to the length of treatment, linkage to care or transmissibility window.
Results A significant decline was detected for the treatment window during 2014–2015 versus the 2 previous years (p=0.0273), while the linkage to care interval remained unchanged during the study period. Inference of the putative source of HIV infections suggested that individuals with a recent diagnosis or narrow transmissibility window (time period between HIV infection and ART initiation) were not sources of HIV infections to other groups. Contrarily, a significant number of HIV infections originated from individuals with longer transmissibility window interval.
Conclusions Our findings showed that the treatment window is decreasing over time, presumably due to the updated treatment guidelines. Our study also demonstrates that people treated earlier after infection do not transmit at high rates, thus documenting the benefits of early ART initiation in preventing ongoing HIV-1 transmission.
- molecular epidemiology
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Handling editor Anna Maria Geretti
Contributors EGK organised the data, did the analysis, and prepared the figures and the manuscript. GA, GX, ML, MC, NM, AS, VP, AA, AP, KP, MP, DB, GC, DimitraP, VP, SK, HS, NVS, ML, PP and EM participated in the study design, performed the data collection and provided critical comments on the manuscript. IH-M, GM, GN and AH contributed to the study design and provided critical comments on the manuscript. DimitriosP (corresponding author) performed the study design and supervision, and contributed to manuscript writing and editing.
Funding This study was supported by Gilead Sciences (IN-GR-292-1874).
Disclaimer This abstract has been translated and adapted from the original English-language content. Translated content is provided on an "as is" basis. Translation accuracy or reliability is not guaranteed or implied. BMJ is not responsible for any errors and omissions arising from translation to the fullest extent permitted by law, BMJ shall not incur any liability, including without limitation, liability for damages, arising from the translated text.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval This research project has been approved by the Ethics Committee of the Medical School, National and Kapodistrian University of Athens (number/ID of the approval: 1516003876).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The whole data set corresponds to a dense sampling of PLHIV in Greece. Therefore, to avoid the risk of PLHIV identification, we may share our data upon reasonable request.
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