According to the CDC announcement, travelers from China, Hong Kong, and Macau to the United States must present a negative PCR or rapid antigen test administered by a healthcare provider no more than 2 days before departure. The requirement applies to air travelers 2 years of age or older regardless of nationality or vaccination status. The requirement also applies to passengers traveling through Incheon International Airport, Toronto Pearson International Airport, and Vancouver International Airport on their way to the United States if they have been in China, Hong Kong, or Macau within the past 10 days, as well as to passengers who are merely transiting through the United States en route to another destination.
Passengers who tested positive more than 10 days before the flight can provide documentation of recovery from COVID-19 in lieu of a negative test result. Airlines will be required to confirm the negative COVID-19 test result or documentation of recovery for all passengers before they board or deny boarding to the passenger.
https://wwwnc.cdc.gov/travel/destinations/traveler/none/china