Reaction to COVID-19 vaccine at prior BCG site. My fiancee received the Bacille Calmette-Guérin (BCG) vaccine as an infant in Mexico, which protects against tuberculosis and leaves a scar as shown. 1/4

The day after receiving the Moderna vaccine she developed a circular redness and itching at the BCG scar (representative photo shown) which self resolved in a couple of hours. Of note it was in the same arm as the vaccine but not at the injection site. 2/4

Interestingly 6 days later the localized circular redness and itching RETURNED at the site of the BCG scar. There were NO concerning features such as difficulty breathing. I gave her Benadryl and the symptoms resolved. I found one similar case online. 3/4 https://www.aaaai.org/ask-the-expert/delayreac">https://www.aaaai.org/ask-the-e...

In sum, if you have a BCG scar then redness & itching at the site of the BCG scar is a possible rare HARMLESS side effect from the Moderna vaccine. We& #39;re thankful to be vaccinated. Get your vaccine as soon as possible. https://abs.twimg.com/emoji/v2/... draggable="false" alt="🙏🏽" title="Gefaltete Hände (mittlerer Hautton)" aria-label="Emoji: Gefaltete Hände (mittlerer Hautton)">4/4

Of note, some people are having this same delayed hypersensitivity reaction in the arm that received the COVID vaccine, who do NOT have the BCG vaccine. It& #39;s harmless and improves with antihistamines. It& #39;s possible the BCG scar has no relevance.