The emerging of a novel coronavirus (COVID-19), first detected in Wuhan city, China in December 2019 curried uncertainty over the key epidemiological, clinical and virological characteristics of the novel pathogen and particularly its ability to spread in the human population and its virulence, and that usually affect the detection and the spread of such disease.

The current guideline is based on the current available knowledge and guidelines of COVID-19 and experiences with MERS-CoV. It may change with evolving situation and when we move to higher epidemic phase (level 5).

Closed settings, such as the household, have a defined population that do not mix readily with the larger surrounding community, and therefore such settings provide a strategic way to track emerging respiratory infections and characterize virus transmission patterns because the denominator can be well defined. In addition, exposure is within the setting, and follow-up of household contacts is generally more feasible in this well-defined setting as compared to an undefined one.