FAA medical certificate requirements are:
Medical certificates are designated as first-class, second-class, or
- First-class is designed for the airline transport pilot
- Second-class for the commercial pilot
- Third-class for the student, recreational and private pilot
Coming to your question, this site states (my highlighting):
... the ICAO naming structure for the various classes of medicals does not
fit with that of the U.S. Under the ICAO definition, a second class
medical applies only to holders of private pilot licenses.
In most States, outside of the U.S. and Canada, it is easier to simply
carry a valid first class medical rather than trying to explain to a
foreign inspector that a FAA second class medical equals an ICAO class
For more information, please read this PDF.