"From Original Antigenic Sin (OAS) to the Universal Influenza Virus Vaccine" (Henry et al.); influenza vaccine has taught us a lot and the prospects are frightening if OAS plays out re COVID vaccine

Simple yet important types of considerations for the challenge is that the first prime or exposure or 'imprinting' will prejudice how one will respond post vaccine; a benign coronavirus can be deadly

The OAS or initial antigen ‘fixation’ or ‘imprinting’ or ‘priming’ can come via natural exposure infection or vaccine. It is the vaccine’s sub-optimal immune pressure that is driving the viral immune escape and infectious variants to emerge due to selection pressure on the spike.

1)Henry et al.: From Original Antigenic Sin to the Universal Influenza Virus Vaccine

2)What you need to know about 'original antigenic sin' with fall COVID boosters around the corner

‘Antibody responses are essential for protection against influenza virus infection. Humans are exposed to a multitude of influenza viruses throughout their lifetime and it is clear that immune history influences the magnitude and quality of the antibody response. The 'original antigenic sin' concept refers to the impact of the first influenza virus variant encounter on lifelong immunity. Although this model has been challenged since its discovery, past exposure, and likely one's first exposure, clearly affects the epitopes targeted in subsequent responses.’