BCG Vaccination at Birth and COVID-19: A Case-Control Study in US Military Veterans

This article was originally published here

Hum Vaccine Immunother. October 13, 2021: 1-8. doi: 10.1080 / 21645515.2021.1981084. Online ahead of print.


In the early stages of the global COVID-19 pandemic, caused by the SARS-CoV-2 virus, low- and middle-income countries (LMICs) appeared to experience lower morbidity and mortality rates than high-income countries, especially the United States. States. Various suggestions put forward to explain this included the possibility that LMICs might gain untargeted benefits from BCG vaccination of infants, intended primarily to protect against tuberculosis. A number of ecological epidemiological studies that examined COVID-19-related morbidity and mortality rates in all countries appeared to support this suggestion. Ecological studies, however, are primarily hypotheses, given their well-known limitations in extrapolation to the individual level. The present study, which used anonymized records of U.S. military veterans treated by the Department of Veterans Affairs, was primarily a case-control study of COVID-19 infections with a retrospective cohort study of nested mortality. infections. The witnesses were a random sample of veterans not recorded as having had COVID-19. There have been 263,039 witnesses and 167,664 cases of COVID-19, of which 5,016 have died. The combination of country and year of birth has been used as a surrogate for BCG vaccination of infants. The study did not support the hypothesis that BCG in early childhood was protective against COVID-19. The odds ratio for infection was 1.07 (95% confidence interval [CI]: 1.03, 1.11) and the relative risk of death among COVID-19 cases was 0.86 (95% CI: 0.63, 1.18). The potential for misclassification of nondifferential exposure was a concern, potentially biasing the association measures toward zero.

IDPM: 34643480 | DOI: 10.1080 / 21645515.2021.1981084

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