The team of Matthieu Mahévas and Pascal Chappert have been following up on their recent work on B cell responses in the context of SARS-CoV-2 infection and mRNA vaccination. Studying memory B cells and plasma cells post SARS-CoV-2 Omicron BA.1 breakthrough infection in individuals previously vaccinated with three doses of the COVID-19 mRNA vaccine, they show clear signs of antigen imprinting from the Hu-1 Spike encoded in the vaccine. However, the diversity of the [...]