It's not "people traveling" as this phrase is commonly understood, that is the issue; it's "relocation of 5% of a small country's population (Nicaragua for example) into the USA".
>Most tuberculosis (TB) cases in the US are diagnosed in foreign-born persons, and undocumented foreign-born may face particular barriers to timely access to health services.
When leaving the USA, getting TB vaccine is highly recommended and (at least in my experience) free and easy. I think it's fairly clear GP meant folks coming into the USA, and not for short periods, from areas that are not able to supply vaccines regularly.
This very well might be an issue. UNICEF and other aid organizations work dilligently to eradicate TB and other poverty-adjacent diseases, so perhaps individuals and the US Gov should increase their aid to other nations.
Unless you plan to lockdown the country entirely, preventing people traveling is not an effective approach.