South Africa: Study Finds HIV-Specific Immune Activity in Central Nervous System Despite Viral Suppression in Blood

What the report says

AllAfrica reported from Rio de Janeiro that researchers presenting at AIDS 2026 found signs of HIV-specific immune activity in the cerebrospinal fluid of some South African adolescents, even though standard blood testing showed the virus was suppressed. The study involved young people who acquired HIV around birth, began antiretroviral therapy in infancy and have been followed for 16 years in the PAVE-80 cohort.

According to the report, the team examined paired blood and cerebrospinal fluid samples from 79 adolescents. While 75% had viral suppression in the blood, 11 of 59 participants in that suppressed group — about 19% — still showed detectable HIV-specific antibody activity in the fluid surrounding the brain and spinal cord. A prior interruption in treatment was more frequent among those with this cerebrospinal fluid response.

Shalena Naidoo of Stellenbosch University said the results do not indicate that participants are ill, that treatment is failing or that care should change. Rather, the findings suggest immune activity in the central nervous system may differ from what clinicians see in blood. The study used a Western blot test, but researchers said it cannot yet show whether the antibodies reflect immune memory, transfer from blood or antibody production within the central nervous system.

The report said the research was cross-sectional, meaning it captured only one point in time. Researchers said further follow-up is needed to determine whether the signal is linked to viral persistence, neuroinflammation, brain structure or cognitive outcomes. The work matters because HIV cure and remission studies often focus on whether viral suppression in blood fully reflects what is happening elsewhere in the body.