Childhood BCG vaccination: no association with SARS-CoV-2 protection in adulthood

  • Hamiel U & al.
  • JAMA
  • 13 May 2020

  • curated by Miriam Davis, PhD
  • Clinical Essentials
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Takeaway

  • Presumed bacille Calmette-Guerin (BCG) vaccination in childhood is not associated with a lower rate of SARS-CoV-2 infection in adults, according to a nationwide cohort study in Israel.

Why this matters

  • The results do not support the proposition that BCG vaccination should be introduced as a preventive intervention against COVID-19.

Study design

  • Nationwide retrospective cohort study comparing infection rates and proportion with SARS-CoV-2 positivity in 2 populations of adults who showed symptoms of COVID-19:
    • 3064 presumed vaccinated adults born 1979-1981, when BCG was "routinely administered" to newborns and before Israel ended its BCG vaccination program in 1983.
    • 2869 presumed unvaccinated adults born 1983-1985, after the program had ended.
  • Funding: None disclosed.

Key results

  • The birth cohorts did not differ in proportions of laboratory-confirmed positive SARS-CoV-2 test results:
    • 11.7% in presumed vaccinated vs 10.4% among presumed unvaccinated.
      • Difference: 1.3% (P=.09).
  • The cohorts also did not differ in the number of positive test results per 100,000 population:
    • 121 among presumed vaccinated vs 100 among presumed unvaccinated (P=.15).

Limitations

  • Observational.
  • Limited number of severe cases.
  • True BCG vaccination exposure unknown.