There are 19th century legal cases backing up travel restrictions to prevent disease spread. It’s not something we’re used to after the mid-20th-century eradication of most major diseases from the USA but there is ample precedent in our constitution and laws for it.
For instance, https://supreme.justia.com/cases/federal/us/186/380/ “ That from an early day the power of the states to enact and enforce quarantine laws for the safety and the protection of the health of their inhabitants has been recognized by Congress is beyond question. That until Congress has exercised its power on the subject, such state quarantine laws and state laws for the purpose of preventing, eradicating, or controlling the spread of contagious or infectious diseases, are not repugnant to the Constitution of the United States although their operation affects interstate or foreign commerce is not an open question. The doctrine was elaborately examined and stated in Morgan Steamship Company v. Louisiana Board of Health, 118 U. S. 455”
For instance, https://supreme.justia.com/cases/federal/us/186/380/ “ That from an early day the power of the states to enact and enforce quarantine laws for the safety and the protection of the health of their inhabitants has been recognized by Congress is beyond question. That until Congress has exercised its power on the subject, such state quarantine laws and state laws for the purpose of preventing, eradicating, or controlling the spread of contagious or infectious diseases, are not repugnant to the Constitution of the United States although their operation affects interstate or foreign commerce is not an open question. The doctrine was elaborately examined and stated in Morgan Steamship Company v. Louisiana Board of Health, 118 U. S. 455”