the greek alphabet. delta, then lamda, mu. there are some that look a little more concerning than others just based on the characteristics of the virus. when i talk to these virologists and i have talked to some arountd world they're not as worried about those as delta. delta was a bad one. we know that. very contagious the way that particular virus rearranged itself. it was a problem. right now there's others that are always going to be on the horizon but not of huge concern. what we do see is the immunity that you have right now from the vaccinations or natural immunity should offer at least some protection against what is coming down the pike. >> we saw the studies at israel and somewhere else that it is waning but still 90% against hospitalizations and deaths. pretty good. to the book. "world war c." catchy. now, why did you want to write this book especially with the