报道里面说是

The tests can be either a PCR test or an antigen self-test administered through a telehealth service.

如果是10天以前阳性的，有医生证明已经好了的，也可以。另外，包括从汉城，多伦多，温哥华来的

The requirement will apply both to passengers flying directly to the United States from China as well to passengers flying through popular third-country gateways, including Seoul, Toronto and Vancouver.

Passengers who test positive more than 10 days before their flight can provide documentation of their recovery in lieu of a negative test result.