A quarantine is a system of rules and practices that prevents the spread of disease by physically segregating people who have been exposed to a contagious disease but have not yet developed symptoms. It is an ethically justifiable method of controlling the spread of a disease, but it also imposes restrictions on human liberty and rights that should be weighed against its expected benefits. Public health emergency preparedness and response (PHEPR) practitioners often have questions about when and whom to implement quarantine, where and how long it should be, and what support strategies might increase its effectiveness and reduce its harms.
In general, quarantine is most likely to be effective when the basic reproductive number (R0) of a pathogen is low and when it has already produced durable immunity in the population. It is also more likely to be effective if it can reliably separate identified individuals from the general population for durations that are consistent with their expected incubation periods.
Quarantine can have significant negative psychological and social consequences for those subjected to it, especially if they are placed in isolation without access to care. The use of public health information and risk communication and the provision of social and emotional support should be priorities in order to mitigate these effects. Likewise, efforts should be made to ensure that those subjected to quarantine have an understanding of the importance of their role in protecting others and controlling the epidemic.