On the relationship between BCG coverage and national COVID-19 outcome: could 'heterologous' herd immunity explain why some countries are better off?
J Intern Med
; 288(6): 682-688, 2020 12.
Article
in English
| MEDLINE | ID: covidwho-892271
ABSTRACT
The COVID-19 pandemic has affected most parts of the global society since its emergence, and the scientific community has been challenged with questions urgently demanding answers. One of the early hypotheses on COVID-19 outcome was that some protection could be offered by the tuberculosis vaccine (BCG), and several clinical studies were initiated along with the emergence of numerous observational studies on the relationship between BCG and COVID-19 severity. In the present work, I demonstrate a strong correlation between the number of years that countries implemented BCG vaccination plans and age-standardized mortality rates during the first months of the pandemic in Europe. Further analyses of age groups in two European countries with comparably few confounding factors and easily identifiable groups of BCG-vaccinated and non-vaccinated subgroups suggest a population-level effect of BCG on national outcomes of COVID-19. This phenomenon of 'heterologous herd immunity' deserves further investigation, both in epidemiological and experimental studies.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
BCG Vaccine
/
Immunization Programs
/
Immunity, Herd
/
COVID-19
Type of study:
Experimental Studies
/
Observational study
/
Prognostic study
/
Randomized controlled trials
Topics:
Vaccines
Limits:
Humans
Country/Region as subject:
Europa
Language:
English
Journal:
J Intern Med
Journal subject:
Internal Medicine
Year:
2020
Document Type:
Article
Affiliation country:
Joim.13198
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