Some Major Differences Between Isolation and Quarantine:

                 Isolation                 Quarantine
Isolation is the separation of infected persons with communicable disease from others in such places/conditions so as to prevent/limit transmission to those susceptible. Quarantine is the restriction of activities of apparently healthy persons who have been exposed to communicable disease during its period of communicability.
In simple words, isolation separates sick/ill people infected with contagious disease from those who are healthy/not sick. In simple words, quarantine separates and restricts the movement of well people who were exposed to a contagious disease to see if they become sick.
It applies to person who are known to be ill with a contagious disease. It applies to those who have been exposed to a contagious disease but who may or may not become ill.
Isolation is done to those who are already infected/diseased. Quarantine is done to those who are apparently healthy.
These people are certainly exposed to the disease. These people may or may not have been exposed to the disease.
E.g.: Hospitals isolate patients with infectious tuberculosis. E.g.: Apparently healthy person travelling from COVID-19 (corona virus disease) affected countries are quarantined for 14 days incubation period.
Isolation is what you do for people who are sick. Quarantine means you recognize that you have been exposed.
The person should be kept in isolation until the point of full recovery from the disease OR up to the period in which disease is considered contagious. The person should be kept in quarantine up to the incubation period of the disease. If any symptoms of disease are seen within the incubation period, he/she should be then kept in isolation until full recovery.
Isolation is mostly preferred in presence or continuous observation of the health worker. Quarantine can be done in home or health care setting with/without continuous observation of the health worker.
Isolated persons must be provided with good medical care and health check-up. Thus, it usually occurs in hospital site. Health condition of a quarantine person should be continuously observed and monitored. He/she should undergo investigative testing.
People in isolation get care for their illness, with safety measures put into place to protect clinicians. E.g. wearing protective outfits etc. Persons in quarantine are moved apart from the person who has not been exposed to illness or disease.
Isolation is effective for all setting to prevent the transmission of disease. Quarantine is a significant defense for limited resource setting, especially for developing countries.