Contact tracing is the process of identifying, assessing, and managing people who have been exposed to a disease to prevent onward transmission. These people are called contacts.
Contact tracing for Covid-19 requires identifying people who may have been exposed to SARS-CoV-2, the virus that causes Covid-19, and following them daily for 14 days. The goal is to stop transmission of the virus by reducing the number of people who are circulating with the virus.
How does contact tracing work?
Contact tracing is a process that includes several steps:
Defining contacts: a contact is a person who has been exposed to someone else infected with the virus that causes Covid-19, from two days before to 14 days after the person started to show symptoms.
Identifying contacts: this is done through an interview with the person infected with the virus that causes Covid-19 to find out who they have been in contact with.
Informing contacts: each contact should be contacted by phone or in person to determine if they meet the definition and then be monitored. Each person confirmed as a contact should be informed about the goal of contact tracing, the process (including how their personal data will be protected) and who to contact with any concerns or questions. Additional essential information should be provided on how and when to quarantine, symptoms to look for, and what to do if the person becomes unwell.
Managing and monitoring contacts daily: the contact person identified should be encouraged and supported to stay in quarantine, which means to separate from others in order to limit the possibility of exposing other people to infection should they become ill. During the quarantine period, daily monitoring should be implemented to monitor their health for any sign of illness. The monitoring ends 14 days after the person was last in contact with the person infected with the virus that causes Covid-19.
Data processes and analysis: The information on each contact person is gathered in a database and updated daily monitoring on the person’s health status. These processes vary from country to country.
Who is defined as a contact?
A contact is defined as anyone who had direct contact or was within 1 metre for at least 15 minutes with a person infected with the virus that causes Covid-19, even if the person with the confirmed infection did not have symptoms. Contacts should remain in self-quarantine during the 14-day monitoring period to limit the possibility of exposing other people to infection should they become ill.
Can contact tracing help in controlling the spread of the virus?
Yes, when systematically applied, contact tracing will break the chains of transmission, meaning that the virus transmission can be stopped. Contact tracing is thus an essential public health tool for controlling infectious diseases.
When should contact tracing be implemented?
Comprehensive contact tracing should be implemented as soon as cases or clusters are identified. During intense transmission, contact tracing may be difficult but should be carried out as much as possible, focusing on vulnerable and household contacts, healthcare workers and high-risk closed settings (e.g., dormitories, institutions, long-term care homes and other long-term facilities).
When countries have passed a peak in transmission and the numbers of sick people are decreasing, particularly when stringent public health and social measures are being adjusted, it is critical to maintain rapid identification of sick people and contact tracing. This identification and investigation breaks new transmission chains of diseases such as Covid-19.
What happens if you are a contact?
If you are a possible contact, you should first be contacted by phone or in person by health authorities to determine if you meet the contact definition, which is anyone who has had direct contact or was within 1 metre for at least 15 minutes with a person infected with Covid-19.
If you are confirmed as a contact, you will then be encouraged and supported to be in quarantine, which means to separate yourself from others, and to monitor your health for any signs of illness.
The monitoring ends 14 days you were last into contact with the person infected with Covid-19.
By participating in contact tracing, you are contributing to controlling the spread of the virus that causes Covid-19 in your area.
Vulnerable people will be protected and more restrictive measures, such as general stay-at-home orders, might be avoided or minimized.
This is an act of solidarity for your community. —WHO.