2024-12-21

Principles for the investigation of individual cases and clusters of COVID-19 disease

This document contains the updated Interim Guidelines published in the Principles for Investigating Individual Cases and Clusters of COVID-19. With the update, this release includes additional information on contact tracing, including a revised figure1 with options for tracing community and healthcare contacts. It also includes the revised isolation rejection criteria. This version has been updated taking into account the current evidence on the spread of SARS-CoV-2, which is the causative agent of COVID-19, as well as virology data. The World Health Organization (WHO) will continue to update these guidelines as new information becomes available. This document provides guidance for local, regional and national health authorities for the rapid investigation of selected suspected cases and clusters of COVID-19.

It is not intended to serve as a comprehensive guide to outbreak investigation, but rather is intended to provide an overview of the key principles for investigating individual cases or clusters of COVID-19. To date, detailed guidelines have been developed for investigating outbreaks of other respiratory pathogens, including MERS-CoV2 and non-seasonal influenza virus3. These guidelines are intended to apply in all countries, but may need to be adjusted during implementation to reflect available resources and COVID-19 transmission rates. For this reason, they should be read in conjunction with WHO’s Interim COVID-19 Preparedness, Preparedness and Response Guidelines.