Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 18 1 2026 02 14 Immunological and virological response in HIV-1 infected patients receiving active antiretroviral therapy at a tertiary care center in Northern India 102 111 Arti Agrawal Department of Microbiology, SN Medical College, Agra, India Anshika Chawla Department of Microbiology, SN Medical College, Agra, India Astha . Department of Microbiology, F.H. Medical College, Agra, India Jitendra Doneria Department of Medicine, SN Medical College, Agra, India Nitu Chauhan Department of Transfusion Medicine, SN Medical College, Agra, India Ayushi Gupta Department of Liberal Arts and Humanities, Jindal School, Sonipat, Haryana, Agra, India Gargi Tyagi Department of Administrative, SN Medical College, Agra, India Parul Garg Department of Microbiology, SN Medical College, Agra, India 2025 07 09 2025 11 06 Background and Objectives: Human Immunodeficiency Virus (HIV) remains a major global health challenge, with limited Indian data on factors influencing treatment outcomes. This study assessed immunological and virological responses and survival determinants among treatment-naïve HIV-1–positive adults. Materials and Methods: A retrospective observational study was conducted at a tertiary care centre from May 2022 to April 2023. Adults (≥18 years) who initiated first-line ART (TDF + 3TC + DTG) between January 2019 and December 2020 with 24-month follow-up were included. Baseline demographics, CD4 count, viral load, and adherence were analysed using descriptive statistics and logistic regression. Results: Of 452 screened patients, 355 were eligible. Mortality at 6, 12, and 24 months was 22%, 26.8%, and 29.9%, respectively, with overall survival of 70.1%. Baseline CD4 count, viral load, adherence, and ART initiation timing significantly influenced outcomes (p < 0.05). Patients with baseline between 200 to 350 had almost 7 times the odds of survival compared to those with <200 cells/µL. Early ART initiation (≤7 days) improved survival (3-fold) and viral suppression (2.4-fold), while adherence >95% was the strongest predictor of success. Older age and high viral load predicted poorer outcomes. Conclusion: Early ART initiation, strict adherence, and favourable baseline markers significantly improved survival and suppression, supporting the “test-and-treat” approach and the UNAIDS 95-95-95 targets. https://ijm.tums.ac.ir/index.php/ijm/article/view/5609 https://ijm.tums.ac.ir/index.php/ijm/article/download/5609/1867