Impacts of HIV-1 and HIV-2 on the occurrence of opportunistic infections among HIV patients using HIV-1 anti-retroviral therapy in Njombe and Dar es Salaam, Tanzania: a retrospective cross sectional study

Introduction:HIV-1 and HIV-2 are globally known human immunodeficiency virus (HIV) types with 55% genetic difference.Partly dominated HIV-2 type is shown to spread to other countries due to immigration and socio-economic interactions.This study aimed to determine sero-prevalence of HIV-1, HIV-2, and HIV-1/2 dual infection, and their impacts on the occurrence of opportunistic infections (OIs) among HIV-positive patients on antiretroviral therapy (ART) in Njombe and Dar es Salaam, Tanzania. Material and methods:A retrospective cross-sectional study was conducted at eight health facilities.A total of 300 participants were recruited.Patients' history of OIs were obtained from patients' files and interviews.SPSS version 26.0 were used for analysis.Ethical clearance was sought from KNCHRE.All participants provided signed informed consent. Results:The mean age of participants was 35 (SD 0.24) years.The general prevalence of HIV-1 was 69%, HIV-2 was 15%, and HIV 1/2 dual infection was 16%.Tuberculosis, Pneumocystis pneumonia, and esophageal candidiasis were common OIs in HIV-1/2 dual infection type (p < 0.001, p = 0.02, p = 0.02, respectively).HIV-2 and HIV-1/2 had two times higher risks of OIs (RR: 1.69, 95% CI: 1.39-2.07%,p < 0.001; and RR: 1.78, 95% CI: 1.51-2.10%,p < 0.001, respectively). Conclusions:The study confirmed the presence of HIV-2 and HIV-1/2 dual infection in Tanzania.Additionally, it showed high-risk of OIs occurrence among HIV-2 and HIV-1/2 people living with HIV (PLHIV).Therefore, the initiation of HIV-2 ART regimen in Tanzania should be established to reduce poor treatment outcomes among HIV-2 and HIV-1/2 PLHIV.