This study only looked at seropositives, either vaccine or natural immunity. That exposure to covid or even its spike (ie vaccine) increases cross reactivity pr

This study only looked at seropositives, either vaccine or natural immunity. That exposure to covid or even its spike (ie vaccine) increases cross reactivity protection isn’t new (this is why we are still using WT based vaccines for revaccination). I still haven’t seen any study on naive omicron infected cross reactivity to other variants, specially over the RBD.