sirens sounded overnight as a line of thunderstorms left thousands of people without power. moderna is now seeking emergency use authorization for an additional covid booster shot. the news comes as doctors warn a new covid subvariant, which is emerging overseas, could show up in the u.s. in the next few weeks. joining us right now is emergency physician dr. jeremy faust. dr. faust, good to see you. so moderna wants approval for all adults to get a fourth shot, unlike pfizer and biontech, which are only seeking another dose for people over 65. so, what do you think about all this? >> thank you for having me. i think fourth doses will be necessary in some people. we'll need a very clear data readout on what exactly is the protection that we are getting from these doses and for how long does it last. some people need third and fourth doses clearly, and others, maybe won't feel so