Bacillus Calmette-Guérin scar flare after an mRNA SARS-CoV-2 vaccine.

A 34-year-old woman presented to our outpatient clinic with swelling and erythema over the site of her childhood Bacillus Calmette–Guerin (BCG) vaccination scar, 7 days after receiving her first dose of the BNT162b2 (Pfizer-BioNTech) messenger ribonucleic acid (mRNA) vaccine against SARS-CoV-2 on