A Nation's Duty to Protect Itself from Contagious Diseases (by Steve C. Halbrook)

A nation must also protect itself from diseases. In Israel, those with leprosy were quarantined (Leviticus 13:45, 46). Protecting others from disease is part of the Sixth Commandment. The outbreak of a deadly contagious disease can easily wipe out thousands. (This is not to be taken as an endorsement of state-imposed vaccinations, as vaccinations themselves can be deadly.) 

Those with dangerous contagious diseases then must be isolated from the general population. When it comes to immigration, border control can help prevent immigrants with diseases from infecting the nation's inhabitants. A legalization process allows immigrants to be screened for diseases before making contact with the general population. 

However, we are not necessarily opposed to citizens of a nation providing medical assistance to those on the border with infectious diseases—so long as measures are carefully taken (e.g., quarantine) to protect the general population.

From Border Meltdown: Biblical Principles to Address our Immigration Crisis by Steve C. Halbrook