exceptionally transmissible...even for those who have been vaccinated and boosted...fortunately, those folks are rarely seen in hospitals...much less, ICUs. The same cannot be said for those who haven't been vaccinated or survived an infection.
This is not that hard to understand...since the vaccines became available, 95-98% of ICU patients have been unvaccinated...keep trying...you'll eventually "Get It" (either the knowledge...or the virus :-))