Ja znalazłem takie info na stronie ambasady Austrii w USA:
REGULATIONS FOR MINORS (under 18)
Accompanied minors under the age of 12 are subject to the same entry requirements and conditions as the adult under whose supervision they are traveling with exception the testing requirement (eg. quarantine if traveling with adult who does not have a certificate of vaccination or recovery).
All minors traveling alone and accompanied minors 12 years of age and older are subject to the same entry requirements and conditions as adults. When entering Austria from a country or territory not listed in Annex 1 or 2 (this applies to travelers from the United States), minors between the age of 12 and 18 accompanied by a person who is in possession of a valid certificate of vaccination or recovery are exempt from registration and quarantine requirements. Such minors must however present a negative COVID-19 test (see requirements in chapter A above) upon entry.