Human cellular machinery and metabolic capacity impose physical constraints on viral replication, limiting peak transmissibility.

“So, our own cellular machinery, the ability of our cells to assemble viral proteins, the ability of ourselves metabolically to do it quick enough, like there's a limit to that. Like we can only do that so quickly. So once that happens, then, you know, a virus has sort of reached its peak transmissibility in a way because our cells physically can't do it quicker than it's already doing it, if that makes sense.”