This is good news, and rare that a CDC director breaks with advisors (it’s more common for FDA to break with their advisory committees).
Basically one could interpret this recommendation to include just about anyone because one just needs (at most) to provide a self-attestation that they qualify. Anyone who can’t stay at home who doesn’t have underlying conditions or is 65+ can probably qualify…for example, those who work with groups of students (outside of a school setting…e.g., coaches, tutors, counselors), take a train/subway to work, live in a congregant setting (eg., college students), eat in institutional cafeterias, etc.
The term ‘underlying conditions’ is also interesting, because what the media has often reported is ‘immunocompromised’ (and that’s what the initial August booster recommendation stated for both Pfizer and Moderna).
But, those with ‘underlying conditions’ that put them at risk for severe covid is much broader than ‘immunocompromised’. For example, overweight (BMI 25-29) and obesity (BMI 30+) are included in this group and nearly 74% of Americans are in one of these groups.