BCG to Protect against Covid-19 in Health Care Workers

To the Editor: Pittet et al. (April 27 issue) 1 report the results of the BCG Vaccination to Reduce the Impact of Covid-19 in Healthcare Workers (BRACE) clinical trial, which assessed the protective effect of bacille Calmette–Guérin (BCG) vaccine against Covid-19. Early in the pandemic, many articles and preprints were published suggesting this association. Although some of these studies directly examined the biologic properties of the BCG vaccine, many other analyses 2,3 used incomplete data sets and occasionally lacked methodologic rigor, resulting in misleading connections between BCG and SARS-CoV-2. 4 Three years after the world came to a standstill and an unprecedented number . . .