The Delta variant now accounts for the vast majority of new COVID-19 infections in the United States. New models suggest the variant is driving a stark increase in daily case counts. Already, hospitals in some communities in Florida have matched their peaks from the days before the vaccines. The CDC has revised its guidelines about who needs to wear a mask and why. In this hour, we talk about what a Delta wave looks like, who is most at risk, and what’s different now as we mark 450 days of the pandemic.