BCG Vaccine-Induced Trained Immunity and COVID-19: Protective or Bystander?
Gopala KoneruGaber El-Saber BatihaAbdelazeem M AlgammalMahmoud MabrokSara MagdyShrouk SayedMai E AbuElmagdReham ElnemrMahmoud M SaadNoura H Abd EllahAmal HosniKhalid MuhammadHelal F HettaPublished in: Infection and drug resistance (2021)
In late 2019, a new virulent coronavirus (CoV) emerged in Wuhan, China and was named as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This virus spread rapidly, causing the coronavirus disease-2019 (COVID-19) pandemic. Bacillus Calmette-Guérin (BCG) is a live attenuated tuberculosis (TB) vaccine, associated with induction of non-specific cross-protection against unrelated infections. This protection is a memory-like response in innate immune cells (trained immunity), which is caused by epigenetic reprogramming via histone modification in the regulatory elements of specific genes in monocytes. COVID-19 related epidemiological studies showed an inverse relationship between national BCG vaccination policies and COVID-19 incidence and death, suggesting that BCG may induce trained immunity that could confer some protection against SARS-CoV-2. As this pandemic has put most of Earth's population under quarantine, repurposing of the old, well-characterized BCG may ensure some protection against COVID-19. This review focuses on BCG-related cross-protection and acquisition of trained immunity, as well as the correlation between BCG vaccination and COVID-19 incidence and mortality.
Keyphrases
- sars cov
- respiratory syndrome coronavirus
- coronavirus disease
- resistance training
- risk factors
- dna methylation
- mycobacterium tuberculosis
- immune response
- gene expression
- transcription factor
- type diabetes
- oxidative stress
- drug induced
- quality improvement
- diabetic rats
- coronary artery disease
- cardiovascular disease
- hiv aids
- pulmonary tuberculosis
- endothelial cells
- human immunodeficiency virus
- body composition
- adverse drug