From the Background: "This document summarises current WHO [World Health Organization] guidance on global surveillance for COVID-19 [coronavirus disease] in humans, caused by infection with COVID-19 virus. This guidance should be read in conjunction with WHO's guidance on preparedness, readiness and response activities, which strongly recommends active case finding and testing as well as contact tracing in all transmission scenarios. Aggregate reporting should be considered a temporary stop-gap measure only when individual case reporting is not possible. WHO will continue to update this guidance as new information about COVID-19 becomes available. [...] What is new:  Updated case definition for a probable case;  Definition of transmission pattern;  Revision of the definition of a contact;  Update on global surveillance with aggregated data reporting."
WHO reference number: WHO/2019-nCoV/SurveillanceGuidance/2020.6
2020 World Health Organization. Posted here with permission. Document is under a Creative Commons license and requires proper attribution and noncommercial use to be shared: [https://creativecommons.org/licenses/by-nc-sa/3.0/igo/]
World Health Organization: https://www.who.int/