In 1920s France, doctor Albert Calmette and veterinarian Camille Guérin discovered a cure for bovine tuberculosis - called the Bacille Calmette-Guérin (BCG) vaccine - and thereby ended up saving millions of lives. Now it looks like a promising new weapon in the fight against Alzheimer’s.
Calmette and Guérin could have never imagined that their research would inspire scientists investigating an entirely different kind of disease a century later. Yet that's what is happening, with several studies suggesting that BCG can protect people from developing Alzheimer’s disease.
If these preliminary results bear out in clinical trials, it could be one of the cheapest and most effective weapons in our fight against dementia. And a wonderfully positive example of the law of unintended consequences.
A pilot study by Coad Thomas Dow of the University of Wisconsin-Madison and his colleagues suggests that BCG injections can effectively reduce plasma amyloid levels, particularly among those carrying the gene variants associated with a higher risk of Alzheimer’s. Although the sample size was small, it has bolstered hopes that immune training will be an effective strategy for fighting the disease.
“The BCG vaccine is safe and globally accessible,” says Marc Weinberg, who researches Alzheimer’s at Massachusetts general hospital in Boston. It is also incredibly cheap compared with the other options, costing just a few pence a dose. Even if it confers just a tiny bit of protection, he says: “It wins the cost-effectiveness contest hands down.”