Gut Bacteria Linked to Latent HIV Levels

Research from the Karolinska Institutet has identified a connection between the composition of gut bacteria and the amount of latent HIV that remains in the blood of individuals receiving antiretroviral therapy. The findings, published in the journal Gut Pathogens on April 9, 2026, suggest that the gut microbiome may influence the size of the viral reservoir.

While antiretroviral treatment is effective at managing the virus, HIV persists in the body in a dormant state known as the viral reservoir. This reservoir is the primary reason a cure for HIV is not currently possible, as the dormant virus remains hidden from the immune system and standard medications.

Study Methodology and Findings

The study involved 30 participants living with HIV who had been on long-term antiretroviral treatment. To understand the relationship between the microbiome and the virus, researchers analyzed blood samples to measure levels of intact HIV DNA.

These measurements were combined with detailed profiling of the participants’ gut microbiota using whole-metagenomic sequencing. This process allowed researchers to map the specific bacterial species and metabolic processes present in the gut.

The results indicated that specific patterns in the gut microbiota were associated with differences in the size of the HIV reservoir. The researchers found that certain bacterial species and metabolic activities differed significantly between individuals with larger and smaller reservoirs.

Specific Bacterial Associations

The research highlighted specific bacterial species that correlated with the size of the latent HIV reservoir:

• Smaller Reservoirs: The presence of species such as Faecalibacterium prausnitzii and Lachnospira sp000437735 was linked to a smaller viral reservoir.
• Larger Reservoirs: The species Prevotella copri, which is frequently associated with inflammation, was more common in individuals who had a larger reservoir.

Beyond specific species, the study identified metabolic processes that differed based on reservoir size. Heightened metabolic processes related to amino acid formation and sugar breakdown were linked to larger viral reservoirs.

We observed that specific patterns in the gut microbiota were associated with differences in the size of the HIV reservoir. This suggests that interactions between the body and the microbiome may influence how much virus remains in a dormant state

Oscar Kieri, doctoral student at the Department of Medicine, Huddinge

Implications for Future Treatment

The discovery that the microbiome is linked to the latent HIV reservoir opens potential new avenues for research into HIV cures. Because standard antiretroviral drugs cannot eliminate the dormant reservoir, targeting the gut microbiome may provide a different approach to reducing the amount of virus persisting in the body.

Researchers suggest that future strategies could involve therapeutically manipulating the gut microbiota. Potential methods for this manipulation include the use of targeted probiotics, specialized diets, or new therapies designed to shrink or eliminate the persistent viral reservoir.

By understanding how specific bacterial species and metabolic pathways influence the dormant state of the virus, medical professionals may eventually develop interventions that complement existing antiretroviral therapies to move closer to a cure.