mi fido più del sito CDC: https://www.cdc.gov/coronavirus/2019-ncov/travelers/proof-of-vaccination.html
Noncitizens, Nonimmigrants (Covered Individuals)
Noncitizens who are nonimmigrants and seeking to enter the United States by air are required to show proof of being fully vaccinated against COVID-19 before boarding a flight to the United States from a foreign country.
If you are not fully vaccinated against COVID-19, you will NOT be allowed to board a flight to the United States, unless you meet the criteria for an exception under the Proclamation and CDC’s Amended Order. A booster dose is not needed to meet this requirement.
Categories of noncitizen nonimmigrants that meet the criteria for an exception under the Proclamation and CDC’s Amended Order include:
Persons on diplomatic or official foreign government travel
Children under 18 years of age
Persons with documented medical contraindications to receiving a COVID-19 vaccine
Participants in certain COVID-19 vaccine trials
Persons issued a humanitarian or emergency exception
Persons with valid visas [excluding B-1 (business) or B-2 (tourism) visas] who are citizens of a foreign country with limited COVID-19 vaccine availability (See list for updates effective June 28, 2022)
Members of the U.S. Armed Forces or their spouses or children (under 18 years of age)
Sea crew members traveling with to a C-1 and D nonimmigrant visa
Persons whose entry would be in the national interest, as determined by the Secretary of State, Secretary of Transportation, or Secretary of Homeland Security (or their designees)
If you travel by air to the United States under one of these exceptions, you will be required to attest that you are excepted from the requirement to present Proof of Being Fully Vaccinated Against COVID-19 based on one of the exceptions listed above. Based on the category of the exception, you may further be required to attest that:
You will be tested with a COVID-19 viral test 3–5 days after arrival in the United States, unless you have documentation of having recovered from COVID-19 in the past 90 days;
You will self-quarantine for a full 5 days, even if the test result to the post-arrival viral test is negative, unless you have documentation of having recovered from COVID-19 in the past 90 days; and
You will self-isolate if the result of the post-arrival test is positive or if you develop COVID-19 symptoms.
Da quanto capisco, potrebbe essere una richiesta e non un obbligo, ma non mi sono documentato abbastanza per darti una risposta certa...