the dominant variant. we've seen that in south africa. we are seeing it in the uk. i'm absolutely certain that is what we're going to be seeing here relatively soon. >> reporter: no need at this point for an omicron specific booster vaccine, says dr. fauci, but this variant is now the most complete escapee say researchers in a new preprint study although the vaccines are still highly effective at preventing severe disease or death. >> it is reassuring these infections seem less severe but that is really only true probably if you are a healthy person who has been immunized ideally with three shots. if we have enough of these infections which it looks like we are going to our health care system has again the potential to be really overwhelmed. >> reporter: those cdc advisers who just voted to say the mrna vaccine should be preferred over johnson & johnson spent hours going through studies that show