air travel – Is there any physician at SFO who issues fit-to-fly certificates?

As a result of the COVID-19 pandemic, to be authorized to board the plane, some countries require a COVID-19 RT-PCR test done than 48 or 72 hours prior to the departure of the flight, followed by a fit-to-fly certificate that must be signed by a physician. This makes it a bit tight to obtain a fit-to-fly certificate in time, especially if the COVID-19 RT-PCR test results take a while to be sent to the passenger. Is there any physician at SFO who issues fit-to-fly certificates?