a booster. i think if i were a marketing person, i certainly wouldn t have called it that. it sort of implies that you are okay. your car is running okay, but if you want the boost it a little bit, take the their shot or the fourth shot. and that s not the case. to be completely and ma am mumly protected, you should get first of all the third shot, because only 30% of americans have gotten it. and if possible, if it s been over four months, get the fourth shot to be as protected as possible. good advice as always. dr. jorge rodriguez, thank you so much for your time. thank you. shanghai, the engine of china s $18 trillion economy is tightening covid restriction was the city of 25 million people now in day three of the covid lockdown. this is happening as the country fights its worst covid surge since the original outbreak in wuhan two years ago. cnn s christy lou stout is following the story and joins us now from hong kong. good to see you, christy.