Bacillus Calmette-Guerin Site Reaction After COVID-19 mRNA Vaccination

This document discusses a series of 5 cases where individuals experienced Bacillus Calmette-Guerin (BCG) site reactions following COVID-19 mRNA vaccination with Pfizer-BioNTech. The patients, aged between 22 and 49, developed erythematous reactions at their BCG scar sites, which were temporary and resolved spontaneously within a few days to a week. The study suggests that these reactions may be due to immune system activation by the vaccine, potentially involving cross-reaction with mycobacterial proteins. The authors conclude that such reactions are likely under-reported but are generally mild and self-limiting.