Infectious disease specialist, Dr. Sandra Bliss Nelson, weighs in on finding that show the Pfizer vaccine is performing well; MIKE SIMPSON: It's holding its effectiveness, basically 90-ish percent, 91%, six months later. So I guess there's two ways to look at it. First is, yeah, six months. That's great. But then another crowd maybe goes, oh, well, maybe it's only six months. Well, it doesn't drop off to 10% the Tuesday after the six-month clock rolls around, right? So it's going to be maybe a sliding scale. We just have to see how far it goes. SANDRA BLISS NELSON: I...