It is important to clarify the usage of several terms as relevant for the current COVID-19 pandemic. In this document:
A contact is defined as someone who had any contact with an infected person (probable or confirmed COVID-19 case) while they were infectious – starting from 2 days before illness onset (or, for asymptomatic clients, 2 days prior to positive specimen collection) until the time the patient is isolated.
Close contact is defined by CDC as someone who was within 6 feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period starting from 2 days before illness onset (or, for asymptomatic patients, 2 days prior to test specimen collection) until the time the patient is isolated. The World Health Organization (WHO) additionally includes persons with direct physical contact with a probable or confirmed case, direct care for a patient with probable or confirmed COVID-19 disease without using proper personal, and other situations as indicated by local risk assessments.
Isolation refers to a strategy used to separate people infected with the SARS-CoV-2 virus (those with and without symptoms) from people who are not infected. The term is used here to refer to people who are isolated at home, a community care center (i.e., isolation shelter), or a health facility. In the home, anyone with COVID-19 symptoms or who has been diagnosed with the disease should separate themselves from otherspdf icon in the home to reduce the risk of transmission to others in the household and should stay home until it is safe for them to be around others. This also includes people who have signs and symptoms consistent with COVID-19, for whom test results are not yet or will not be available.
Quarantine refers to a strategy used to keep someone who might have been exposed to COVID-19, but does not know if he or she is infected, away from others. Quarantine helps prevent spread of disease that can occur before a person knows that he or she is infected. People in quarantine should stay home, separate themselves from others, monitor their health, and follow directions from their local public health authorities.
Case Investigator refers to someone who will interview the case, elicit names and contact information of the contacts to be monitored, and provide guidance and resources to support people who are in isolation. They may also be the person who initially notifies a patient of a positive test result.
Contact Tracer refers to someone who will notify contacts of their exposure and monitor them for 14 days. They will describe quarantine to the contacts, help connect contacts with social services and other support as needed, and commonly be the primary public health person for contacts to answer questions and address concerns.
For the purpose of this document, these two distinct roles are referenced. However, the roles and responsibilities of case investigator and contact tracer may overlap in some settings, and may change over the course of the response. For example, in some contexts, case investigators may be the ones who initially notify contacts of their exposure; this is commonly the case for household members of the case. In addition, these roles may have different titles in different places.