Bacillus Calmette-Guerin (BCG): the adroit vaccine
Background: The Bacillus Calmette-Guerin (BCG) vaccine has been in use for 99 years, and is regarded as one of the oldest human vaccines known today. It is recommended primarily due to its effect in preventing the most severe forms of tuberculosis, including disseminated tuberculosis and meningeal...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
AIMS Press
2021-02-01
|
| Series: | AIMS Microbiology |
| Subjects: | |
| Online Access: | http://www.aimspress.com/article/doi/10.3934/microbiol.2021007?viewType=HTML |
| _version_ | 1818945938543083520 |
|---|---|
| author | Oluwafolajimi A. Adesanya Christabel I. Uche-Orji Yeshua A. Adedeji John I. Joshua Adeniyi A. Adesola Chibuike J. Chukwudike |
| author_facet | Oluwafolajimi A. Adesanya Christabel I. Uche-Orji Yeshua A. Adedeji John I. Joshua Adeniyi A. Adesola Chibuike J. Chukwudike |
| author_sort | Oluwafolajimi A. Adesanya |
| collection | DOAJ |
| description | Background:
The Bacillus Calmette-Guerin (BCG) vaccine has been in use for 99 years, and is regarded as one of the oldest human vaccines known today. It is recommended primarily due to its effect in preventing the most severe forms of tuberculosis, including disseminated tuberculosis and meningeal tuberculosis in children; however, its efficacy in preventing pulmonary tuberculosis and TB reactivation in adults has been questioned. Several studies however have found that asides from its role in tuberculosis prevention, the BCG vaccine also has protective effects against a host of other viral infections in humans, an effect which has been termed: heterologous, non-specific or off-target.
Objectives:
As we approach 100 years since the discovery of the BCG vaccine, we review the evidence of the non-specific protection offered by the vaccine against viral infections, discuss the possible mechanisms of action of these effects, highlight the implications these effects could have on vaccinology and summarize the recent epidemiological correlation between the vaccine and the on-going COVID-19 pandemic.
Results:
Several epidemiological studies have established that BCG does reduce all-cause mortality in infants, and also the time of vaccination influences this effect significantly. This effect has been attributed to the protective effect of the vaccine in preventing unrelated viral infections during the neonatal period. Some of such viral infections that have been investigated include: herpes simplex virus (HSV), human Papilloma virus (HPV), yellow fever virus (YFV), respiratory syncytial virus (RSV) and influenza virus type A (H1N1). These effects are thought to be mediated via induction of innate immune memory as well as heterologous lymphocytic activation. While epidemiological studies have suggested a correlation, the potential protection of the BCG vaccine against COVID-19 transmission and mortality rates is currently unclear. Ongoing clinical trials and further research may shed more light on the subject in the future.
Conclusion:
BCG is a multifaceted vaccine, with many numerous potential applications to vaccination strategies being employed for current and future viral infections. There however is a need for further studies into the immunologic mechanisms behind these non-specific effects, for these potentials to become reality, as we usher in the beginning of the second century since the vaccine's discovery. |
| first_indexed | 2024-12-20T08:07:04Z |
| format | Article |
| id | doaj.art-58ca30c143a444fab8acee5ea2fb3fa1 |
| institution | Directory Open Access Journal |
| issn | 2471-1888 |
| language | English |
| last_indexed | 2024-12-20T08:07:04Z |
| publishDate | 2021-02-01 |
| publisher | AIMS Press |
| record_format | Article |
| series | AIMS Microbiology |
| spelling | doaj.art-58ca30c143a444fab8acee5ea2fb3fa12022-12-21T19:47:22ZengAIMS PressAIMS Microbiology2471-18882021-02-01719611310.3934/microbiol.2021007Bacillus Calmette-Guerin (BCG): the adroit vaccineOluwafolajimi A. Adesanya0Christabel I. Uche-Orji1Yeshua A. Adedeji 2John I. Joshua3Adeniyi A. Adesola4Chibuike J. Chukwudike51. Institute for Advanced Medical Research and Training (IAMRAT), College of Medicine, University of Ibadan, Ibadan, Nigeria 2. Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria2. Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria2. Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria2. Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria2. Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria. Department of Medicine, College of Medicine, University of Ibadan, Ibadan, NigeriaBackground: The Bacillus Calmette-Guerin (BCG) vaccine has been in use for 99 years, and is regarded as one of the oldest human vaccines known today. It is recommended primarily due to its effect in preventing the most severe forms of tuberculosis, including disseminated tuberculosis and meningeal tuberculosis in children; however, its efficacy in preventing pulmonary tuberculosis and TB reactivation in adults has been questioned. Several studies however have found that asides from its role in tuberculosis prevention, the BCG vaccine also has protective effects against a host of other viral infections in humans, an effect which has been termed: heterologous, non-specific or off-target. Objectives: As we approach 100 years since the discovery of the BCG vaccine, we review the evidence of the non-specific protection offered by the vaccine against viral infections, discuss the possible mechanisms of action of these effects, highlight the implications these effects could have on vaccinology and summarize the recent epidemiological correlation between the vaccine and the on-going COVID-19 pandemic. Results: Several epidemiological studies have established that BCG does reduce all-cause mortality in infants, and also the time of vaccination influences this effect significantly. This effect has been attributed to the protective effect of the vaccine in preventing unrelated viral infections during the neonatal period. Some of such viral infections that have been investigated include: herpes simplex virus (HSV), human Papilloma virus (HPV), yellow fever virus (YFV), respiratory syncytial virus (RSV) and influenza virus type A (H1N1). These effects are thought to be mediated via induction of innate immune memory as well as heterologous lymphocytic activation. While epidemiological studies have suggested a correlation, the potential protection of the BCG vaccine against COVID-19 transmission and mortality rates is currently unclear. Ongoing clinical trials and further research may shed more light on the subject in the future. Conclusion: BCG is a multifaceted vaccine, with many numerous potential applications to vaccination strategies being employed for current and future viral infections. There however is a need for further studies into the immunologic mechanisms behind these non-specific effects, for these potentials to become reality, as we usher in the beginning of the second century since the vaccine's discovery.http://www.aimspress.com/article/doi/10.3934/microbiol.2021007?viewType=HTMLbcgnon-specific effectsvaccinetuberculosiscovid-19 |
| spellingShingle | Oluwafolajimi A. Adesanya Christabel I. Uche-Orji Yeshua A. Adedeji John I. Joshua Adeniyi A. Adesola Chibuike J. Chukwudike Bacillus Calmette-Guerin (BCG): the adroit vaccine AIMS Microbiology bcg non-specific effects vaccine tuberculosis covid-19 |
| title | Bacillus Calmette-Guerin (BCG): the adroit vaccine |
| title_full | Bacillus Calmette-Guerin (BCG): the adroit vaccine |
| title_fullStr | Bacillus Calmette-Guerin (BCG): the adroit vaccine |
| title_full_unstemmed | Bacillus Calmette-Guerin (BCG): the adroit vaccine |
| title_short | Bacillus Calmette-Guerin (BCG): the adroit vaccine |
| title_sort | bacillus calmette guerin bcg the adroit vaccine |
| topic | bcg non-specific effects vaccine tuberculosis covid-19 |
| url | http://www.aimspress.com/article/doi/10.3934/microbiol.2021007?viewType=HTML |
| work_keys_str_mv | AT oluwafolajimiaadesanya bacilluscalmetteguerinbcgtheadroitvaccine AT christabeliucheorji bacilluscalmetteguerinbcgtheadroitvaccine AT yeshuaaadedeji bacilluscalmetteguerinbcgtheadroitvaccine AT johnijoshua bacilluscalmetteguerinbcgtheadroitvaccine AT adeniyiaadesola bacilluscalmetteguerinbcgtheadroitvaccine AT chibuikejchukwudike bacilluscalmetteguerinbcgtheadroitvaccine |