Two studies published in the Journal of Alzheimer’s Disease (Feb. 19-20, 2024) report that a 100-year-old TB vaccination may reduce the likelihood of developing dementia. Have you ever heard of Bacillus Calmette-Guérin? I didn’t think so. Most people in the US are unfamiliar with BCG. But this very old vaccine could change the future of Alzheimer’s research.
Two French scientists, Albert Calmette and Camile Guérin were performing bacteriologic research around the turn of the 20th century. Together they helped develop a live attenuated vaccine against tuberculosis that was named after them: Bacillus Calmette-Guérin or BCG for short.
The first BCG jab was administered more than 100 years ago in 1921. It worked quite well to ward off TB infections caused by the germ Myocobacterium tuberculosis.
BCG Remains Popular Around the World:
Because tuberculosis has mostly been eliminated from the US and western Europe, people rarely get BCG shots there anymore. But it is still widely administered to infants and children in countries where TB is still a potential problem.
That makes BCG one of the most commonly administered vaccines in the world. Public health authorities administer BCG shots in countries like Albania, Algeria, Angola, Bangladesh, Bulgaria, Cambodia, Gambia, Ghana, Hong Kong, Malaysia, South Korea, Singapore and Thailand, to name just a few.
BCG: The First Cancer Immunotherapy:
Decades ago researchers at the National Cancer Institute reported that BCG could be used to treat bladder cancer (Science, Dec. 11, 1970). This very first immunotherapy is still a mainstay in the treatment of this kind of malignancy (Current Opinion in Urology, May, 2019).
Researchers admit that they don’t exactly understand how BCG works to control bladder cancer:
“Despite the use of BCG in the clinic for a significantly long time, the mechanism behind its therapeutic efficacy still lacks clarity. Urothelial cells and cells of the immune system including CD4+ and CD8+ T cells, natural killer cells, granulocytes, macrophages, and dendritic cells have been previously shown to be critically involved in the therapeutic effect of BCG. Evidence show[s] that attachment and internalization of BCG results in the secretion of cytokines and presentation of BCG and/or cancer cell antigens to the immune cells for the activation of the tumor protective immune response.”
There is also evidence that BCG works against metastatic melanoma (Journal of Internal Medicine, Dec. 2020). And a study published in the journal Vaccine (Feb. 19, 2024) reported that having a BCG scar was associated with less chronic illness, including chronic respiratory and allergic diseases.
Infections and Dementia:
There is growing evidence that brain infections are involved in the development of dementia. The Alzheimer’s Society states it this way:
“There is an increasing amount of research into the link between certain infections and dementia, including herpes, pneumonia, syphilis, Lyme disease and gum disease. Research shows that dementia is more common in people who have these infections.”
Research published in JAMA Network Open, Jan. 3, 2023 concludes:
“This cohort study investigated the association between HWI [hospitalization with infection] and incident dementia over 32 years of follow-up in the ARIC [Atherosclerosis Risk in Communities] study. Participants with any HWI had an approximately 70% increased risk of dementia. Greater measures of association were found for urinary tract, blood and circulatory system, and hospital-acquired infections.”
“These findings bolster support for the hypothesis that infections contribute to the causes of dementia. Furthermore, they highlight that the risk of dementia differs by infection type, suggesting that specific pathophysiological aspects of an infection might affect dementia risk.”
Vaccines Against Alzheimer’s Disease?
We have written about the possibility that both the shingles vaccines and antiviral medications might be beneficial against Alzheimer’s disease at this link (“Shingles Vaccines Against Dementia & Flu Shots vs. Heart Attacks“) and this link (“Do Cold Sores Increase the Risk for Alzheimer’s Disease?“).
We have also asked “Will Flu Shots Protect You from Alzheimer Disease?” And we provide some data to support this possibility.
Can the BCG Vaccine Protect Against Alzheimer’s Disease?
Two articles “in press” were published as abstracts in the Journal of Alzheimer’s Disease on Feb. 19 and Feb. 20, 2024.
Here is the essence of Part I in the words of the authors:
“Vaccines such as Bacille Calmette-Guérin (BCG) can apparently defer dementia onset with an efficacy better than all drugs known to date, as initially reported by Gofrit et al. (PLoS One14, e0224433), now confirmed by other studies. Understanding how and why is of immense importance because it could represent a sea-change in how we manage patients with mild cognitive impairment through to dementia.”
The reference by Gofrit (PLoS One, Nov. 7, 2017) was titled “…BCG Therapy Lowers the Incidence of Alzheimer’s Disease in Bladder Cancer Patients”
The authors of that research report that:
“Bladder cancer patients treated with BCG were significantly less likely to develop AD [Alzheimer’s disease] at any age than patients who were not so treated. This finding of a retrospective study suggests that BCG treatment might also reduce the incidence of AD in the general population.”
Part 2 of the article in the Journal of Alzheimer’s Disease (Feb. 19, 2024) notes that:
“There is growing awareness that infections may contribute to the development of senile dementia including Alzheimer’s disease (AD), and that immunopotentiation is therefore a legitimate target in the management of diseases of the elderly including AD… Five studies to date have determined that intravesicular BCG administration, the standard of care for bladder cancer, is followed by a mean ∼45% reduction in subsequent AD development in these patients. Although this could potentially be ascribed to confounding factors, the finding that other routine vaccines such as against shingles (herpes zoster virus) and influenza (influenza A virus), among others, also offer a degree of protection against AD (mean 29% over multiple studies) underlines the plausibility that the protective effects are real… We conclude that BCG and similar agents merit far wider consideration as prophylactic agents against dementia.”
Final Words:
The Food and Drug Administration has approved new anti-amyloid drugs to treat Alzheimer’s disease. Although the company that made aducanumab (Aduhelm) has abandoned this drug, it is forging ahead with a similar medication called lecanemab (Leqembi). Read our perspective at this link: The Aduhelm Boondoggle Against Alzheimer’s Goes Belly Up.
We anticipate that the FDA will soon approve a similar medication called donanemab. None of these drugs prevent or reverse the symptoms of AD. They will cost tens of thousands of dollars annually, not including ancillary expenses such as brain scans or hospitalizations.
Could BCG Be Better Than Mabs?
Compared to new AD drugs, BCG and the other vaccines discussed above are incredibly affordable. If they do indeed prevent dementia in a portion of the population they will be a valuable investment.
We wish the big funders of research such as the Alzheimer’s Association and the NIH would think more creatively. Billions of dollars have been wasted developing anti-amyloid drugs that neither prevent Alzheimer’s disease nor reverse its devastating decline. Maybe it’s time to look for other solutions to what is rapidly becoming the health crisis of the 21st century.
A Few More Words:
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