Just so there is no ambiguity or confusion, the CDC defines being fully vaccinated as those who have had two weeks or 14 days pass since they received a single dose COVID-19 shot, or the same period of time after their second dose in a two-shot series. Anyone who falls outside of these definitions is required to produce a negative COVID test result, taken no later than 24 hours before a journey. The new travel restrictions apply to all travelers who are arriving in the United States, regardless of whether they are US citizens, immigrants, or non-immigrants.
It is important to note that the CDC has made provisions so that the unvaccinated can travel, but this will mean getting a negative PCR test within 24 hours before you fly. Travelers who have had COVID can also produce what is called a “documentation of recovery” — which proves you have had the illness but are cleared to travel — and this is good for 90 days (via USA Today).