Publications by Year: 2025

2025
Kostaki EG, Papadimitriou E, Chatzopoulou F, Roussos S, Tsirogianni E, Psichogiou M, Goulis I, Kalamitsis G, Kefala AM, Skoura L, et al. Molecular investigation of a new HIV-1 outbreak among people who inject drugs in Greece: evidence for a dense network of HIV-1 transmission. Sex Transm InfectSex Transm InfectSex Transm Infect. 2025.Abstract
OBJECTIVES: Αn HIV-1 outbreak was identified among people who inject drugs (PWID) in Thessaloniki, Greece, during 2019-2021. We aimed to investigate the characteristics of this outbreak by means of molecular epidemiology. METHODS: We analysed 57 sequences from PWID sampled in Thessaloniki during 2019-2023. Phylogenetic trees were inferred using all subtype A sequences from PWID sampled since 1999 in Greece and reference sequences (n=4824). Phylodynamic analysis was performed using the Bayesian birth-death skyline serial model. RESULTS: Most of the 57 study sequences belonged to sub-subtypes A6 (49, 86%) and A1 (4, 7%). Phylogenetic analysis revealed that two (50%) A1 sequences clustered together and 47 (95.9%) A6 sequences fell within three PWID-specific phylogenetic clusters. The 99.6% and 77.9% of pairwise genetic distances within the largest and second largest PWID clusters were lower than 0.015 substitutions/site. Using a more stringent threshold (0.0015 substitutions/site), we identified five networks of sequences from PWID infected within 1 year. The effective reproduction number (R(e)) started to increase at the beginning of 2019 and remained high almost until the end of 2021. The estimated time from HIV-1 infection to diagnosis showed an increasing trend during 2020-2023 (p<0.001). CONCLUSIONS: The regional clustering of the PWID sequences and their low genetic divergence confirm its local spreading and the recent nature of the outbreak. Using a stringent genetic distance threshold, we showed that HIV-1 transmission occurred among large groups of PWID. The time of epidemic growth coincided with the time of the initial identification, and HIV-1 transmission continued at high rates until 2021.
Sperle I, Seyler T, Pericoli F, Duffel E, Hutchinson S, Jauffret-Roustide M, Kåberg M, Ķīvīte-Urtāne A, Seguin-Devaux C, Sypsa V, et al. Standardising monitoring data on drug-related infectious diseases among people who inject drugs in Europe – an update of the European Union Drugs Agency technical protocol, 2024. Euro Surveill. [Internet]. 2025;30(30)::pii=2500007. Publisher's Version
Polaris Observatory Collaborators. Number of people treated for hepatitis C virus infection in 2014-2023 and applicable lessons for new HBV and HDV therapies. J Hepatol. 2025.Abstract
BACKGROUND & AIMS: The year 2023 marked the 10-year anniversary of the launch of direct-acting antivirals (DAAs) for the treatment of hepatitis C virus (HCV). Monitoring HCV treatment trends by country, region, and globally is important to assess progress toward the World Health Organization's 2030 elimination targets. Additionally, the historical patterns can help predict the treatment uptake for future therapies for other liver diseases. METHODS: The number of people living with HCV (PLHCV) treated between 2014-2023 across 119 countries was estimated using national HCV registries, reported DAA sales data, pharmaceutical companies' reports, and estimates provided by national experts. For the countries with no available data, the average estimate of the corresponding Global Burden of Disease region was used. RESULTS: An estimated 13,816,000 (95% uncertainty intervals: 13,221,000-16,415,000) PLHCV were treated, of whom 12,748,000 (12,226,000-15,231,000) were treated with DAAs, of which 11,081,000 (10,542,000-13,338,000) were sofosbuvir-based DAA regimens. Country-level data accounted for 97% of these estimates. In high-income countries, there was a 41% drop in treatment from its peak, and reimbursement was a large predictor of treatment. In low- and middle-income countries, price played an important role in expanding treatment access through the public and private markets, and treatment continues to increase slowly after a sharp drop at the end of the Egyptian national program. CONCLUSIONS: In the last 10 years, 21% of all HCV infections were treated with DAAs. Regional and temporal variations highlight the importance of active screening strategies. Without program enhancements, the number of treated PLHCV stalled in every country/region, which may not reflect a lower prevalence but may instead reflect the diminishing returns of existing strategies. IMPACT AND IMPLICATIONS: Long-term hepatitis C virus (HCV) infection can lead to cirrhosis and liver cancer. Since 2014, these infections can be effectively treated with 8-12 weeks of oral therapies. In 2015, the World Health Organization established targets to eliminate HCV by 2030, which included treatment targets for member countries. The current study examines HCV treatment patterns across 119 countries and regions from 2014 to 2023 to assess the impact of national programs. This study can assist physicians and policymakers in understanding treatment patterns within similar regions or income groups and in utilizing historical data to refine their strategies in the future.
Papalamprakopoulou Z, Roussos S, Ntagianta E, Triantafyllou V, Kalamitsis G, Dharia A, Sypsa V, Hatzakis A, Talal AH. Considerations for equitable distribution of digital healthcare for people who use drugs. BMC Health Services Research. 2025;25:531.Abstract
Telehealth holds the potential to expand healthcare access for people who use drugs (PWUD). However, limited data exist on their digital infrastructure access, a prerequisite for telehealth participation. We studied digital healthcare accessibility among PWUD.
Engeli V, Roussos S, Demiris N, Hatzakis A, Sypsa V. Social Contact Patterns and Age Mixing before and during COVID-19 Pandemic, Greece, January 2020-October 2021. Emerg Infect Dis [Internet]. 2025;31:75-85. Website