Our pandemic of COVID-19 (SARS-CoV-2 or severe acute respiratory syndrome coronavirus 2) has brought a flurry of laboratory investigations about this virus. One of the most recent and most interesting research theories is called “original antigenic sin (OAS).” In my own non-scientific explanation, this means a person’s first response to a virus has a remarkable effect on their response to a similar or variant virus. Our body responds much the same way to a variant as it did to the original ...