14 CFR Part 382 Nondiscrimination on the Basis of Disability in Air Travel (Air Carrier Access Act) (with amendments issued through May 2016)

(c)

(1) You may also require a medical certificate for a passenger if he or she has a communicable disease or condition that could pose a direct threat to the health or safety of others on the flight.

(2) For purposes of this paragraph, a medical certificate is a written statement from the passenger's physician saying that the disease or infection would not, under the present conditions in the particular passenger's case, be communicable to other persons during the normal course of a flight. The medical certificate must state any conditions or precautions that would have to be observed to prevent the transmission of the disease or infection to other persons in the normal course of a flight. A medical certificate under this paragraph must be dated within 10 days of the date of the flight for which it is presented.