BCG Vaccine Does Not Reduce COVID-19 Risk for Health Care Workers

THURSDAY, April 27, 2023 (HealthDay News) -- The bacille Calmette-Guérin (BCG) vaccine does not result in lower risk for COVID-19 for health care workers, according to a study published in the April 27 issue of the New England Journal of Medicine.

Laure F. Pittet, Ph.D., from the Murdoch Children's Research Institute at the University of Melbourne in Australia, and colleagues randomly assigned health care workers to receive the BCG-Denmark vaccine or saline placebo and followed them for 12 months. The primary outcomes were symptomatic COVID-19 and severe COVID-19, assessed at six months. A total of 3,988 participants underwent randomization; owing to the availability of COVID-19 vaccines, recruitment ceased before the planned sample size was reached.

The researchers found that the estimated risk for symptomatic COVID-19 was 14.7 and 12.3 percent by six months in the BCG and placebo groups, respectively (risk difference, 2.4 percentage points; 95 percent confidence interval, −0.7 to 5.5; P = 0.13). The risk for severe COVID-19 by six months was 7.6 and 6.5 percent in the BCG and placebo groups, respectively (risk difference, 1.1 percentage points; 95 percent confidence interval, −1.2 to 3.5; P = 0.34). Most participants who met the trial definition of severe COVID-19 were not hospitalized. The risk differences were similar, but confidence intervals narrower, in supplementary and sensitivity analyses using less conservative censoring rules.

"BCG-Denmark vaccination did not reduce the risk of COVID-19 in health care workers, and the results did not exclude the possibility of an increased risk," the authors write.

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