Original antigenic sin (OAS) or immune imprinting, immune fixation or prejudice; Fujita et al. proves the "impact of imprinted immunity induced by mRNA vaccination in an experimental animal model"

by Paul Alexander

showed experimental data suggesting the existence of imprinted immunity by vaccination in hamsters




‘The concept of "imprinted immunity" suggests that individuals vaccinated with ancestral virus-based vaccines may not develop effective immunity against newly emerging Omicron subvariants, such as BQ.1.1 and XBB.1. Here, we investigated this possibility using hamsters. While natural infection induced effective antiviral immunity, breakthrough infections in hamsters with BQ.1.1 and XBB.1 Omicron subvariants after receiving the 3-dose mRNA-LNP vaccine resulted in only faintly induced humoral immunity, supporting the possibility of imprinted immunity.’

‘These observations raise a possible concept called “imprinted immunity”—prior exposure to a primary antigen (e.g., ancestral SARS-CoV-2 in this case) can attenuate the induction magnitude of immunity against certain secondary antigens (e.g., Omicron subvariants) [9, 11-13].’

Christof Plothe shared this with me.