variant of covid-19 may not show any symptoms and thus don t even know to take a test. in china, covid cases are on the rise. and now nearly 400 million people across 45 cities in china are under full or partial lockdown as part of china s strict zero covid policy. and this could end up having a major economic impact all around the world. let me bring in cnn reporter matt is here with us, matt egan. what s that risk here? what is the big risk? you are trying to ease the world s manufacturing powerhouse. when something breaks there, we feel it everywhere. and stuff is definitely breaking there because of these lockdowns in china. we ve already seen all these different impacts. freight traffic frozen. cargo flights canceled. 90% of the trucks that deal with imports or exports out of traffic. it s essentially at a standstill. all of that has to do with the flow of supplies. we ve also seen the production of new supplies get impacted.