B1 vaccines have been tested in humans, the B4 and 5 only on mice/animals, so that may be why Canada is pushing this one? The USA seems okay with the lack of human trials.Why would we use a vaccine against BÀ.1 if we have a vaccine against 4 and 5? Are you thinking that because the first vaccine is available and ready to go, we should take it now and just wait till the newer vaccine becomes available? Excuse my ignorance, but I got distracted during my August hospital stay and stopped following Covid news.
mRna technology itself has been tested on millions.