its completely safe as long as neither are sick.
Just because you're not showing symptoms doesn't mean you're not infected. Asymptomatic carriers, silent but active vectors, have been understood by medical science for over a century. Immunosuppresed people will carry them more easily because their immune system's diminished response can go undetected. Immunosuppressed people can also lose their vaccine granted immunity simply because their immune system stops generating the required antibodies.
Absolutely no contact.