Isolation / Quarantine

To contain the spread of a contagious illness, public health authorities rely on many strategies. Two of these strategies are isolation and quarantine. Both are common practices in public health, and both aim to control exposure to infected or potentially infected persons. Both may be undertaken voluntarily or compelled by public health authorities. The two strategies differ in that isolation applies to persons who are known to have an illness, and quarantine applies to those who have been exposed to an illness but who may or may not become ill.

Isolation: For People Who Are Ill

Isolation refers to the separation of persons who have a specific infectious illness from those who are healthy and the restriction of their movement to stop the spread of that illness. Isolation allows for the focused delivery of specialized health care to people who are ill, and it protects healthy people from getting sick. People in isolation may be cared for in their homes, in hospitals, or in designated healthcare facilities. Isolation is a standard procedure used in hospitals today for patients with tuberculosis (TB) and certain other infectious diseases. In most cases, isolation is voluntary; however, many levels of government (federal, state, and local) have basic authority to compel isolation of sick people to protect the public.

During an infectious outbreak, patients in the United States may be asked to isolate themselves until they are no longer infectious. This practice will allow patients to receive appropriate care, and help contain the spread of the illness. Seriously ill patients will be cared for in hospitals or designated facilities. Persons with mild illness may be cared for at home. Persons being cared for at home may be asked to avoid contact with other people and to remain at home until their public health department or healthcare provider authorize release from voluntary isolation.

Quarantine: For People Who Have Been Exposed But Are Not Ill

Quarantine refers to the separation and restriction of movement of persons who, while not yet ill, have been exposed to an infectious disease and therefore may transmit the disease to others. Quarantine of exposed persons is a public health strategy, like isolation, that is intended to stop the spread of infectious disease. Quarantine is medically very effective in protecting the public from disease.

States generally have authority to declare and enforce quarantine within their borders. The provisions cited under the Michigan Emergency Management Act (Act 390) and the Public Health Code (Act 368) provide broad authorities to take actions to control epidemics and prevent the spread of disease. Public health officials can limit public gatherings, prohibit the presence of individuals in specific locations, and require the detention and/or treatment of individuals with communicable diseases. This law may be used to detain individuals within a circumscribed area and to exclude healthy persons from entering the area. Warning notices will be issued to individuals believed to be a carrier of the disease and they will be required to cooperate with public health infection control measures.

The Centers for Disease Control and Prevention (CDC), through its Division of Global Migration and Quarantine, also is empowered to detain, medically examine, or conditionally release persons suspected of carrying certain communicable diseases. This authority derives from section 361 of the Public Health Service Act (42 U.S.C. 264), as amended.

Quarantine can be enacted with different disease-causing agents or diseases in mind. In recent years, CDC advised persons who were exposed to SARS, but not symptomatic, to monitor themselves for symptoms and advised home isolation and medical evaluation if symptoms appeared. Individual quarantine was an integral part of the control measures used in countries severely affected by the 2003 SARS outbreak. Quarantine of large groups was used only in selected settings where extensive transmission was occurring.

:: back to the top ::