Quarantine and Isolation
The Centers for Disease Control and Prevention (CDC) is the U.S. government agency responsible for identifying, tracking and controlling the spread of disease. With the help of the CDC, state and local health departments have created emergency preparedness and response plans. In addition to early detection, rapid diagnosis and treatment with antibiotics or anti-virals, these plans use two main traditional strategies — quarantine and isolation — to contain the spread of illness. These are common health care practices to control the spread of a contagious disease by limiting people’s exposure to it.
The difference between quarantine and isolation can be summed up like this:
- Quarantine applies to those who have been exposed to a contagious disease but who may or may not become ill.
- Isolation applies to persons who are known to be ill with a contagious disease.
When someone is known to be ill with a contagious disease, he or she is placed in isolation and receives special care with precautions taken to protect uninfected people from exposure to the disease. When someone has been exposed to a contagious disease and it is not yet known if he or she has caught it, the person may be quarantined or separated from others who have not been exposed to the disease. For example, he may be asked to remain at home to prevent further potential spread of the illness. He also receives special care and observation for any early signs of the illness.
Modern quarantine lasts only as long as necessary to protect the public by (1) providing public health care (such as immunization or drug treatment, as required) and by (2) ensuring that quarantined persons do not infect others if they have been exposed to a contagious disease.
Modern 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 duration and scope of quarantine measures would vary, depending on their purpose and what is known about the incubation period (how long it takes for symptoms to develop after exposure) of the disease-causing agent. Examples include:
- A few hours for assessment. Passengers on airplanes, trains or boats believed to be infected with or exposed to a dangerous contagious disease might be delayed for a few hours while health authorities determine the risk they pose to public health. Some passengers may be asked to provide contact information and then released while others who are ill are transported to where they can receive medical attention. There have been a few instances where state and local public health authorities have imposed a brief quarantine at a public gathering, such as a shelter, while investigating if one or more people may be ill.
- Enough time to provide preventive treatment or other intervention. If public health authorities determine that a passenger or passengers on airplanes, trains or boats are sick with a dangerous contagious disease, the other passengers may be quarantined in a designated facility where they may receive preventive treatment and have their health monitored.
- For the duration of the incubation period. If public health officials determine that one or more passenger on airplanes, trains or boats are infected with a contagious disease and that passengers sitting nearby may have had close contact with the infected passenger(s), those at risk might be quarantined in a designated facility, observed for signs of illness and cared for under isolation conditions if they become ill.
Isolation would last for the period of communicability of the illness, which varies by disease and the availability of specific treatment. Usually it occurs at a hospital or other health care facility or in the person’s home. Typically, the ill person will have his or her own room and those who care for him or her will wear protective clothing and take other precautions, depending on the level of personal protection needed for the specific illness.
In most cases, isolation is voluntary; however, federal, state and local governments have the authority to require isolation of sick people to protect the public.