Quarantine is an idea that stirs a mix of emotions and opinions. It is a tool in the toolbox of public health to combat emerging infectious diseases, and it attracts heightened interest during episodes of perceived or real epidemics. However, it is not an intuitive concept to most. Many people have a hard time wrapping their heads around quarantine, and it is often misunderstood.

A quarantine is an isolation of a person or group to prevent the spread of an illness. Isolation can be done at home, in hospital, or in designated healthcare facilities. Quarantine is used only for certain serious illnesses, including cholera, diphtheria, infectious tuberculosis, plague, smallpox, yellow fever, and viral hemorrhagic fevers such as SARS. Other illnesses are not deemed to be of concern, such as chicken pox and cancer, because they are usually not highly contagious and have effective treatment.

Quarantine is not the only response to an emerging infectious disease, but it has proven one of the most important tools in controlling outbreaks. The effectiveness of a quarantine depends on the circumstances of each exposure, including how much the infectious agent spreads in a community, how long the incubation period is, and whether the vaccine can be administered to reduce transmission rates. Quarantine should be imposed only if the scientific evidence supports it, and public health officials must be transparent in explaining the justification for their actions. Individuals placed under quarantine have a duty to comply with the order and must be assisted in their discharge of this obligation, which includes providing food and shelter, accommodating them at work or school, and not penalizing them for discharging their duties.