Molecular Typing of HIV-1 Subtypes Circulating Among Antiretroviral Naive Patients in Anambra State

HIV-1 exhibits extraordinary genetic diversity, with distinct subtypes and circulating recombinant forms (CRFs) dominating different geographic regions. Molecular surveillance of HIV-1 subtypes is important for understanding local transmission dynamics, vaccine design, and the performance of diagnostic assays. This study determined the HIV-1 subtype distribution among antiretroviral therapy (ART)-naive patients attending HIV clinics in Anambra State, South East Nigeria. Blood samples from 100 confirmed HIV-1-positive patients were collected, and viral RNA was extracted. The gag and env gene regions were reverse-transcribed, amplified by nested PCR, and subjected to direct Sanger sequencing. Phylogenetic analysis was performed to classify subtypes and CRFs. Subtype G was the predominant subtype identified, consistent with reports from South East Nigeria. Subtype CRF02_AG, a predominant West African CRF, was the second most common classification. A small proportion of sequences clustered with unique recombinant forms, reflecting ongoing recombination. These molecular epidemiology data will inform regional HIV surveillance programmes and support diagnostic kit evaluation in Anambra State. Keywords: HIV-1 subtypes, molecular epidemiology, antiretroviral naive, phylogenetic analysis, Anambra State