Primary Navigation for the CDC Website
CDC en Español


Global Migration and Quarantine

Facts about Isolation and Quarantine

  • By Executive Order of the President, federal isolation and quarantine are authorized for these communicable diseases:

  • Cholera
  • Diphtheria
  • Infectious tuberculosis
  • Plague
  • Smallpox
  • Yellow fever
  • Viral hemorrhagic fevers
  • SARS
  • Flu that can cause a pandemic

  • The President can revise this list by Executive Order.

PDF version of this Fact Sheet
(PDF Icon PDF 118 KB/2 pages)

Isolation and quarantine

Isolation and quarantine are public health practices used to stop or limit the spread of disease.

Isolation is used to separate ill persons who have a communicable disease from those who are healthy. Isolation restricts the movement of ill persons to help stop the spread of certain diseases. For example, hospitals use isolation for patients with infectious tuberculosis.

Quarantine is used to separate and restrict the movement of well persons who may have been exposed to a communicable disease to see if they become ill. These people may have been exposed to a disease and do not know it, or they may have the disease but do not show symptoms. Quarantine can also help limit the spread of communicable disease.

Isolation and quarantine are used to protect the public by preventing exposure to infected persons or to persons who may be infected.

 In addition to serving as medical functions, isolation and quarantine also are “police power” functions, derived from the right of the state to take action affecting individuals for the benefit of society.

Federal law

The federal government derives its authority for isolation and quarantine from the Commerce Clause of the U.S. Constitution.

Under section 361 of the Public Health Service Act (42 U.S. Code § 264), the U.S. Secretary of Health and Human Services is authorized to take measures to prevent the entry and spread of communicable diseases from foreign countries into the United States and between states.

The authority for carrying out these functions on a daily basis has been delegated to the Centers for Disease Control and Prevention (CDC).

CDC’s role

Under 42 Code of Federal Regulations parts 70 and 71, CDC is authorized to detain, medically examine, and release persons arriving into the United States and traveling between states who are suspected of carrying these communicable diseases.

As part of its federal authority, CDC routinely monitors persons arriving at U.S. land border crossings and passengers and crew arriving at U.S. ports of entry for signs or symptoms of  communicable diseases.

When alerted about an ill passenger or crew  member by the pilot of a plane or captain of a ship, CDC may detain passengers and crew as  necessary to investigate whether the cause of the illness on board is a communicable disease.

State, local, and tribal law

States have police power functions to protect the health, safety, and welfare of persons within their borders. To control the spread of disease within their borders, states have laws to enforce the use of isolation and quarantine.

These laws can vary from state to state and can be  specific or broad. In some states, local health authorities implement state law. In most states, breaking a quarantine order is a criminal misdemeanor.

Tribes also have police power authority to take actions that promote the health, safety, and welfare of their own tribal members. Tribal health authorities may enforce their own isolation and quarantine laws within tribal lands, if such laws exist.

Who is in charge

The federal government

State, local, and tribal authorities

It is possible for federal, state, local, and tribal health authorities to have and use all at the same time separate but coexisting legal quarantine power in certain events. In the event of a conflict, federal law is supreme.

Enforcement

If a quarantinable disease is suspected or identified, CDC may issue a federal isolation or quarantine order.

Public health authorities at the federal, state, local, and tribal levels may sometimes seek help from police or other law enforcement officers to enforce a public health order.  

U.S. Customs and Border Protection and U.S. Coast Guard officers are authorized to help enforce federal quarantine orders.

Breaking a federal quarantine order is punishable by fines and imprisonment.

Federal law allows the conditional release of persons from quarantine if they comply with medical monitoring and surveillance.

Federal quarantine rarely used

Large-scale isolation and quarantine was last enforced during the influenza (“Spanish Flu”) pandemic in 1918–1919.

In recent history, only a few public health events have prompted federal isolation or quarantine orders:

During the 2003 outbreak of SARS, CDC did not issue isolation or quarantine orders. However, CDC did conduct active surveillance, visual screening of passengers, and handed out Travel Health Alert Notices.

Page last modified: January 22, 2008

Navigation for the DGMQ Website

• Topic Contents