It's not mRNA-based, but if they included a tiny trace amount of a sugar molecule called alpha-gal:
Alpha-gal syndrome is a recently identified type of food allergy to red meat and other products made from mammals. In the United States, the condition is most often caused by a Lone Star tick bite. The bite transmits a sugar molecule called alpha-gal into the person's body. In some people, this triggers an immune system reaction that later produces mild to severe allergic reactions to red meat, such as beef, pork or lamb, or other mammal products.
It's not mRNA-based, but if they included a tiny trace amount of a sugar molecule called alpha-gal:
Alpha-gal syndrome https://www.mayoclinic.org/diseases-conditions/alpha-gal-syndrome/symptoms-causes/syc-20428608