Evidence summary: What are the most recent international definitions for a close contact of COVID-19 case, particularly with regard to enclosed settings such as offices or schools?

There appears to be strong consensus on the definition of a close contact as within a 2 metre distance for greater than 15 minutes with the exception of the World Health Organisation who instead specify a distance of 1 metre; and Japan, where the distance has recently been reduced from 2 metres to 1 metre. Documents relating to criteria for schools, offices or other work settings are included. Among the agencies and governments reviewed, only Ireland, Australia and Tasmania have indicated a timeframe of greater than 2 hours as part of the parameters to be considered in risk assessments of closed spaces. Among the additional criteria that should be taken into consideration when designating a close contact are: the correct use of appropriate PPE ; type of activity; room ventilation; face-to-face or side-by-side interaction; direct contact with infectious secretions including aerosol-generating procedures; period of infectivity; cumulative interpretation of time exposures.