Don't lie and don't carry these things. Don't add to the illusion of "everyone's vaxxing". If asked about it, ask an embrassing medical question in response. "How many STDs have you had?" , "what were the results of your last prostate exam?" , "How cold was the speculum at the gyno's office?". Then state you can't believe people think it's okay to ask for private medical information.

But please, please don't make the vaxxed population appear larger. You just may push a fence sitter onto the vaxxed side.