Public Health Preparedness
ISOLATION AND QUARANTINE
Public health authorities rely on many strategies to contain the spread of a contagious illness. Two of these strategies are isolation and quarantine.
Isolation applies to persons who are known to have an illness, while quarantine applies to those who have been exposed to an illness, but who may or may not become ill.
What does isolation refer to?
Isolation refers to the separation of persons who have a specific infectious illness from those who are healthy. Isolation allows for the treatment of ill persons, 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. In most cases, isolation is voluntary; however, federal, state and local health officials have authority to compel isolation of sick people to protect the public.
What does quarantine refer to?
Quarantine refers to the separation and restriction of movement of persons who, while not yet ill, have been exposed to an infectious agent and therefore may become infectious. Quarantine may be used when:
- A person or a well-defined group of people have been exposed to a highly dangerous and highly contagious disease,
- Resources are available to care for quarantined people and
- Resources are available to implement and maintain the quarantine and deliver essential services.
Quarantine includes a range of disease control strategies that may be used individually or in combination, including:
- Short-term, voluntary home confinement.
- Restrictions on travel by those who may have been exposed.
- Restrictions on passage into and out of an area.
Other measures to control the spread of disease may include:
- Restrictions on the assembly of groups of people (for example, school events).
- Cancellation of public events.
- Suspension of public gatherings and closings of public places (such as theaters).
- Closure of mass transit systems or broad restrictions on travel by air, rail or water.
These measures are used in combination with other public health tools, such as:
- Enhanced disease surveillance and symptom monitoring.
- Rapid diagnosis and treatment for those who become ill.
- Preventive treatment for quarantined individuals, including vaccination or prophylactic treatment, depending on the disease.
Quarantine is more likely to involve limited numbers of exposed persons in small areas than to involve large numbers of persons in whole neighborhoods or cities. The small areas may be though of as “rings” drawn around individual disease cases. Examples of “rings” include:
- People on an airplane or cruise ship on which a passenger is ill with a suspected contagious disease for which quarantine can serve to limit exposure to others.
- People in a stadium, theater or similar setting where an intentional release of a contagious disease has occurred.
- People who have contact with an infected person whose source of disease exposure is unknown—and therefore may be due to a covert release of a contagious disease.
In the event of a large-scale disease outbreak or “pandemic,” there may be dozens of small “rings,” each one including the people exposed to a single case of disease.
The Kalamazoo County Health & Community Services Department has the authority to declare and enforce quarantine within its borders. 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.
What are some examples of the use of isolation and quarantine?
Isolation is a standard procedure used in hospitals today for patients with tuberculosis (TB) and certain other infectious diseases. During the 2003 global SARS outbreak, patients in the United States were isolated until they were no longer infectious. This practice allowed patients to receive appropriate care, and it helped contain the spread of the illness. Seriously ill patients were cared for in hospitals. Persons with mild illness were cared for at home. Persons being cared for at home were asked to avoid contact with other people and to remain at home until ten days after the resolution of fever, provided respiratory symptoms were absent or improving. The CDC advised persons who were exposed but not symptomatic to quarantine themselves (i.e. stay at home), monitor themselves for symptoms and seek medical evaluation if symptoms appeared. This was effective in controlling the spread of the disease.