Overview
- A year-long, single-center pilot published in Communications Medicine reported that BCG vaccination produced persistent ‘trained immunity’ changes in cerebrospinal fluid, showing the vaccine can remodel immune activity around the brain.
- In people without Alzheimer’s pathology the study found decreased amyloid‑beta in CSF and increased amyloid in blood, a compartmental shift that could reflect altered transport or clearance of the protein.
- BCG also made immune cells in CSF and blood more responsive to challenges without raising markers of chronic inflammation, which researchers say is important because sustained inflammation can harm brain tissue.
- The results come from two open‑label 12‑month trials that enrolled 23 adults aged 55 and older who received two intradermal BCG doses, and the study was small, nonrandomized, and not designed to prove prevention.
- Investigators have applied to the NIH for funding of a large pragmatic, placebo‑controlled prevention trial to test whether BCG‑driven immune training reduces cognitive decline; if funded, the study will measure clinical outcomes and the safety of broader use in older adults.