BCG Vaccine-The Road Not Taken.

Area of Science:

• Immunology
• Infectious Diseases
• Neurology

Background:

• The Bacillus Calmette-Guérin (BCG) vaccine is a cornerstone in tuberculosis prevention, administered globally to billions.
• Routine BCG vaccination was not adopted by some countries, like the US, and has been discontinued in others, including Western Europe and Australia.
• Recent research explores BCG's potential beyond tuberculosis, focusing on its immunomodulatory properties.

Purpose of the Study:

• To review the impacts of BCG vaccination policies, particularly the consequences of its discontinuation in Western nations.
• To explore the potential role of Mycobacterium avium ss. paratuberculosis (MAP) as an unrecognized NTM pathogen in various diseases.
• To highlight the renewed interest in BCG for novel applications in infectious, autoimmune, and neurodegenerative diseases.

Main Methods:

• Literature review of BCG vaccination policies and their epidemiological consequences.
• Analysis of studies investigating non-tuberculous mycobacteria (NTM), including MAP, in relation to human diseases.
• Examination of current clinical trials evaluating BCG for non-tuberculosis related conditions.

Main Results:

• Discontinuation of BCG may correlate with increased rates of tuberculosis, NTM infections, autoimmune diseases (diabetes, multiple sclerosis), and neurodegenerative diseases (Parkinson's, Alzheimer's).
• Mycobacterium avium ss. paratuberculosis (MAP) is proposed as a potential NTM pathogen implicated in these conditions.
• BCG's immunomodulatory capacity is being investigated for treating diverse diseases, suggesting potential for broader application.

Conclusions:

• Decisions to discontinue BCG vaccination may have unforeseen public health consequences, potentially increasing susceptibility to various infectious and chronic diseases.
• Further research into NTM, particularly MAP, is warranted to understand their role in autoimmune and neurodegenerative disorders.
• BCG's established safety profile and immunomodulatory effects position it as a promising candidate for expanded therapeutic uses, potentially reversing trends seen in regions that ceased its use.