but here's thing, we don't know how much of a threat this variant really is to us. we know it's got a lot of mutations, but we don't know how rapidly it spreads. it would have to outcompete the delta variant. viruses are trying to find a home. they're trying to find a host. the delta variant has a huge advantage because it's so highly transmissable. there's signs of trouble with this, but we don't know clinically whether it will spread to the extent that delta is or even more. griff: c. siegel, we're hearing across the country that this new omicron is a variant of concern, as you mentioned it, but what does that mean? >> well, it means two things. first -- it means three things. first of all, is it going to be more severe than the other variants of the virus in terms of the disease it causes. that hasn't happened yet. looking back at pandemic histories, viruses tend to get with milder over time because they want to survive.