Original Antigenic Sin is a real phenomenon. It seems not only to permanently influence the immune response to the spike protein itself, but also to inhibit the development of antibodies to other SARS-2 proteins. A worst case scenario, would be a future spike mutation that entirely escapes the anti-spike antibodies elicited by our vaccines. In this case, it seems possible that many vaccinated people will be stuck with permanently suboptimal immune responses. If Omicron is indeed circulating primarily among the vaccinated, as some data suggests, this would seem to be one possibly reason why. These concerns are particularly acute in the case of children, who may well be exposed to the risk of very serious illness in the future, if vaccination permanently misdirects their immune system.