A major challenge in curing HIV-1 is the persistence of latent proviruses in resting CD4+ T cells. These proviruses remain transcriptionally inactive and are not eliminated by antiretroviral therapy (ART). However, recent research has revealed that a significant portion of these proviruses—approximately 11.7%—are replication-competent and have intact genomes and functional long terminal repeats (LTRs). These noninduced proviruses, which were previously thought to be defective, are integrated into active transcription units and have unmethylated promoters, suggesting they could be activated in vivo. This finding indicates that the size of the latent reservoir may be up to 60-fold greater than previously estimated, significantly increasing the barrier to HIV-1 cure. The study analyzed 213 noninduced proviral clones from patients on ART and found that 88.3% had identifiable defects, while 11.7% were intact. These intact proviruses were reconstructed and shown to replicate with kinetics comparable to induced proviruses. The presence of replication-competent noninduced proviruses suggests that the latent reservoir is much larger than previously thought, which has important implications for cure strategies. The study also demonstrated that these proviruses can be induced in vivo, as shown by the ability of repeated PHA stimulation to activate some noninduced proviruses. The findings highlight the challenges in accurately measuring the size of the latent reservoir and the limitations of current assays. The study provides a molecular basis for understanding the discrepancy between PCR and culture assays of LR size and suggests that the true size of the latent reservoir may be significantly larger than previously estimated. This has important implications for the development of cure strategies, including the "shock and kill" approach, which aims to reactivate latent proviruses and then eliminate them. The results indicate that a large, unmeasured population of replication-competent proviruses may exist, making the task of eradicating HIV-1 more challenging. The study also underscores the importance of molecular characterization of noninduced proviruses in understanding the full extent of the challenge posed by the latent reservoir.A major challenge in curing HIV-1 is the persistence of latent proviruses in resting CD4+ T cells. These proviruses remain transcriptionally inactive and are not eliminated by antiretroviral therapy (ART). However, recent research has revealed that a significant portion of these proviruses—approximately 11.7%—are replication-competent and have intact genomes and functional long terminal repeats (LTRs). These noninduced proviruses, which were previously thought to be defective, are integrated into active transcription units and have unmethylated promoters, suggesting they could be activated in vivo. This finding indicates that the size of the latent reservoir may be up to 60-fold greater than previously estimated, significantly increasing the barrier to HIV-1 cure. The study analyzed 213 noninduced proviral clones from patients on ART and found that 88.3% had identifiable defects, while 11.7% were intact. These intact proviruses were reconstructed and shown to replicate with kinetics comparable to induced proviruses. The presence of replication-competent noninduced proviruses suggests that the latent reservoir is much larger than previously thought, which has important implications for cure strategies. The study also demonstrated that these proviruses can be induced in vivo, as shown by the ability of repeated PHA stimulation to activate some noninduced proviruses. The findings highlight the challenges in accurately measuring the size of the latent reservoir and the limitations of current assays. The study provides a molecular basis for understanding the discrepancy between PCR and culture assays of LR size and suggests that the true size of the latent reservoir may be significantly larger than previously estimated. This has important implications for the development of cure strategies, including the "shock and kill" approach, which aims to reactivate latent proviruses and then eliminate them. The results indicate that a large, unmeasured population of replication-competent proviruses may exist, making the task of eradicating HIV-1 more challenging. The study also underscores the importance of molecular characterization of noninduced proviruses in understanding the full extent of the challenge posed by the latent reservoir.