Mexico-U.S. Border closed for migrants, non-essential travel

42 USC 265 authorizes the Surgeon General of the United States to designate countries as a source of dangerous "communicable disease" and "prohibit the introduction of persons and property" from such countries.  The Trump administration has announced such a ban.  Those who "illegally" cross the border will not be held for "processing" but rather will be immediately returned to Mexico or their country of origin "to the extent feasible".  The Administration will doubtless claim that this public health measure overrides the treaty and statutory duty to consider applications for asylum, or to avoid removal for fear of torture. - gwc

Detention Facilities

Customs and Border Protection is the first line of defense of our nation’s borders. To help prevent the introduction of COVID-19 into our border facilities and into our country, aliens subject to the order will not be held in congregate areas for processing by CBP and instead will immediately be turned away from ports of entry.
Those encountered between ports of entry after illegally crossing the border similarly will not be held in congregate areas for processing and instead, to the maximum extent feasible, will immediately be returned to their country of last transit. These aliens are processed in stations designed for short-term processing, where distancing is not a viable option, creating a serious danger of an outbreak.  
The Centers for Disease Control and Prevention (CDC) has determined that these conditions present a serious infection control challenge and are a risk to public health. Should an outbreak occur at these facilities, local medical facilities would be forced to devote extensive resources and may become overwhelmed.   

This action will also protect the health of our country’s dedicated border agents and other law enforcement personnel, who are vital to the security of our Nation.

Apprehension of illegal immigrants along both borders between POEs:

• Migrants from Coronavirus Impacted Areas: Since the beginning of the FY20 fiscal year in October 2019 through the end of February 2020 (over the period of October 1, 2019 to February 29, 2020), foreign nationals from 122 separate countries have been apprehended or denied entry (inadmissible) at the U.S. Southwest border, for a total of over 190,000 apprehended or inadmissible migrants from countries currently with confirmed COVID cases.
• Size and Scale: Every week, CBP apprehends between 7,000 – 9,000 individuals between ports of entry —the equivalent of 2.5 Diamond Princess cruise ships per week.
• Human-to-human Spread: The spread of coronavirus is exacerbated by human-to-human transmission and the need for detention. CBP law enforcement facilities are for short-term holding and do not provide for needed large-scale isolation, diagnosis, or treatment of such a novel disease.
• CBP Facilities: CBP facilities are not structured or equipped to effectively quarantine an infected population. CBP would be forced to rely on state and local hospitals to provide longer-term medical care for individuals who fall ill, further burdening our strained healthcare system and depriving Americans of key medical resources.

Although CBP has policies and procedures in place to handle transmittable diseases, COVID-19 will impact already strained holding capacities and place an extreme burden on what is forecasted to be a stretched healthcare system and the nation’s critical medical professionals who are needed to attend to U.S. citizens and legal residents.  

Migrants should shelter-in-place in their homes and communities, rather than attempting a long and dangerous journey to the United States borders at the hands of traffickers and smugglers.

U.S. Citizens:

U.S. citizens, lawful permanent residents and certain other travelers are exempt from this action. They will receive the same processing, evaluation and potential CDC medical screening that all entrants undergo at U.S. Ports of Entry.

Authority:

Effective at March 21, 2020 at 12:00 a.m. EDT, CBP will, as authorized, implement CDC authority under 42 U.S.C. § 265 to prohibit entry of certain persons into the United States. CBP will assist the Department of Health and Human Services’ (HHS) and U.S. Centers for Disease Control and Prevention (CDC) to protect against the spread of the novel coronavirus (COVID-19) by implementing the emergency authorities under 42 U.S.C. § 265 at the nation’s land borders to prohibit the introduction of certain persons in the interest of public health.