SUMMARY: Original Antigenic Sin (OAS) is a well researched concept dating back to the 1950’s.  When a vaccine is mismatched with the virus it is supposed to target there can be 3 possible outcomes: Neutral (No Impact); Good (Limited Protection); or BAD (Original Antigenic Sin).  OAS can trigger a situation in which the body is tricked into delaying it’s defense mechanism, resulting in much more severe infection, increased risk for hospitalization & death.