COVID-19-Contact-Tracing What is Contact Tracing?

What is Contact Tracing?

Updates as of November 28, 2022:

  • Updated to include latest CDPH definition of who is considered a 'close contact' for contact tracing purposes.

What is contact tracing?

Contact tracing is a public health practice that health departments use to identify and notify people who have been exposed to someone with an infectious disease. Public health workers reach out to these exposed people to tell them that they've been in close contact with an infected person and to give them information and support to help them keep themselves and their loved ones safe. Public health departments have used contact tracing for decades to fight the spread of infectious diseases like measles, tuberculosis, syphilis, and HIV/AIDS.

What is a "close contact" for COVID-19?

Someone who has shared the same indoor space that is less than 400,000 cubic feet in size (for example, homes, waiting rooms, airplanes, etc.) with an infectious person for a total of 15 minutes or more within a 24-hour period is considered to be a "close contact" for COVID-19, regardless of how close they were to the infectious person in that indoor space. This may include people living in the infected person's home, caregivers, classmates, and co-workers who were in a shared indoor airspace with the infectious person when they were contagious.

In very large indoor spaces over 400,000 cubic feet in size (for example, warehouses, large retail stores, manufacturing facilities, etc.) someone is only considered to be a close contact if they have been within 6 feet of an infectious person for a total of 15 minutes or more within a 24-hour period.

A person with COVID-19 may release virus into the air when they cough, sneeze, sing, speak, or even just breathe. This may cause virus particles to build up in smaller indoor airspaces over time and infect others who share that indoor space with them, even if they are more than 6 feet away. While someone is more likely to become infected if they were within 6 feet of a person with COVID-19, the longer someone is sharing an enclosed airspace with an infectious person, especially if the room or space is poorly ventilated, the greater the risk that the exposed person will become infected.

What does contact tracing look like for COVID-19?

People who have tested positive for COVID-19 infection may receive a phone call or a short survey by text from their health department, asking them who they may have exposed while they were contagious. Those "close contacts" are then called or sent a text to let them know about their possible exposure to the virus. When contacts are told about their exposure, information about who exposed them is kept strictly confidential by law; public health workers do not share the name of the person who exposed them. There are a few ways that a person might be informed about a possible exposure to COVID-19. They might:

  • Be notified directly by a personal contact who recently tested positive.
  • Be notified by their work or school setting.
  • Receive an anonymous notification from
  • Receive a call from a public health contact tracer.
  • Receive a digital alert or text message from one of California's notification tools, including CA Notify and the Virtual Assistant.

If you are notified that you have tested positive for COVID-19

You may be asked to speak with a case investigator or answer questions in a survey sent to you by text message from your state or local health department. In the phone interview or survey, you may be asked:

  • Who you were near when you were likely infectious, so these people can be anonymously notified (your name will not be used) that they may have been exposed to COVID-19.
  • If you have CA Notify activated on your phone, please use the system as soon as possible to anonymously alert those who you may have exposed. Learn how to notify others.
  • Whether you have symptoms, have been vaccinated, or have had COVID-19 before.
  • If you need support or more information, including when to get medical care if needed.

You will never be asked for information about your finances or payment options, social security number, or immigration status.

Please see What to Do If You Test Positive webpage for more information on what to do after testing positive for COVID-19.

If you are notified that you may have been exposed to someone with COVID-19

You may be asked to speak with a contact tracer or answer questions in a survey sent to you by text message from your state or local health department. Or you may receive information on what you should do if you are exposed, without being asked to speak with anyone or respond to a survey. In the phone interview, survey questions, or information sent, you may be asked about or provided with the following information:

  • What it means to possibly be exposed to COVID-19 and next steps to take, including how to isolate (stay home and away from others) if symptoms develop or you test positive.
  • What COVID-19 symptoms you may be experiencing or should look for over the 10 days following your last contact with someone with COVID-19.
  • When you should get tested to see if you have been infected with the virus that causes COVID-19.
  • What recommendations you should follow to protect yourself and your family, friends, and community from further spread of COVID-19. This includes encouraging you to wear a mask indoors and around others, especially those at higher risk for severe COVID-19, for 10 days after exposure.
  • Whether you have been vaccinated or boosted or have had COVID-19 before. You are encouraged to get vaccinated or boosted if you have not done so, and information on making a vaccination appointment should be provided.
  • How to get support for testing and when to get treatment.

You will never be asked for information about your finances or payment options, social security number, or immigration status.

Please see What to Do If You Have Been Exposed webpage for more information on what to do when you learn you have been near someone with COVID-19.

How you can participate

Contact tracing works when you answer the call or text and follow the recommendations to protect yourself and others.

Contact tracing is an important and confidential way to do your part. The more people answer the call or text and follow the recommendations, the better we can stop this disease from impacting more lives in California. Your participation is critical to making this effort succeed, and your information is always kept confidential.

The sooner we can reach you, the sooner you can get advice, testing, and the support you need. Early awareness helps you protect your community and loved ones from exposure and illness. And early medical care can improve your outcome if you do get sick.

All you have to do is answer the phone call or respond to the text message survey from the number 23393, sent by your local health department, and follow their recommendations for masking, getting tested, watching your symptoms, notifying others who may have been exposed to you, and getting medical care and treatment.

How your information is kept private

Your identity and health information that you provide is always kept confidential. It will not be shared with anyone who may have been exposed.

California's strict privacy laws protect all your information. California Connected, our state's COVID-19 contact tracing program, maintains information with strict privacy and security standards. The information is only collected and stored for use by local and state public health departments.

Please see the California Connected Privacy Policy, CDPH Privacy Policy and Web Use Policy for additional information.

California (CA) Notify

CA Notify is a digital COVID-19 contact tracing tool based on the Google and Apple Exposure Notification system. CA Notify helps to notify participants who have opted into the program that they were recently near another participant who has since tested positive for COVID-19.

The exposure notification system works by using Bluetooth technology to exchange anonymous keys between cell phones that come close to one another. Identities and locations are not shared, so everyone's privacy is protected.

Only people who opt in and activate the system will be able to receive these exposure alerts. CA Notify assists with contact tracing by providing exposure notifications to people who the infected person may not even know. If you want to learn how to activate it on your phone, or if you have received an alert saying you may have been exposed, visit the CA Notify website for more information.

If you had CA Notify activated on your phone and later tested positive for COVID-19, you are encouraged to use the system to anonymously alert those who were also using CA Notify and may have been near you when you were able to spread the disease.

Virtual Assistant

The Virtual Assistant is an automated system from California Connected used to support you as part of your local health department's contact tracing efforts. The Virtual Assistant may ask you to complete a contact tracing survey and can also provide confidential and safe symptom check-ins through text messages.

You may receive a text with a link sent by the Virtual Assistant from the phone number 23393. It is safe to click on the link in this text message to start communicating with the Virtual Assistant. You may receive links for Surveys, FAQs, or the Symptom Monitoring System. You can reply STOP at any time to stop receiving messages. All information collected is protected and will be used exclusively for public health purposes.

So, if you see a message from 23393, answer the text. Click the link. Help stop the spread of COVID-19 in California.

Please see the Virtual Assistant's Legal Policides (Terms and Conditions) at the end of this page and the Virtual Assistant Questions & Answers: Answering the Text from 23393 for additional information.

Other resources

Safe Schools for All Hub

California's Safe Schools for All Hub consolidates key resources and information related to COVID-19 and schools. It includes interactive maps to see school district, charter school, and private school COVID-19 information and resources. New resources are added to the Hub on a regular basis.

Support for workers

If you work, your employer may be required to provide you with paid sick leave and other benefits. Read more about employee and workplace policies on reducing COVID-19 risk and reporting outbreaks.

If you need childcare, find help with licensed childcare near you. Subsidies may be available. Check your local childcare resource and referral agency to see if you qualify.

If you're an immigrant, you can find support on the Help for Immigrants webpage.

Know that you are not alone

Pandemics can be stressful. Fear and anxiety about a new disease and what could happen can be overwhelming and cause strong emotions.

Coping with stress in a healthy way will make you, the people you care about, and your community stronger. If you feel like you need to talk to someone for emotional support, see this list of resources.

California Connected Privacy Policy

California Civil Code section 1798.17 et seq. requires notice to individuals providing information as part of this program. This includes information collected by the Virtual Assistant Case Survey, Virtual Assistant Exposed Contact Survey, Virtual Assistant Symptom Monitoring Service, or by phone calls, email, text messages, and School/Shared Portal for Outbreak Tracking (SPOT). The information is being requested by the Division of Communicable Disease Control,

PO Box 997377, MS 0500,

Sacramento, California, 95899-7377;

(833) 422-4255;

The information requested as part of this program is authorized by California Health and Safety Code section 120130 and 120140, and Title 17 of the California Code of Regulations section 2505. Submission of the information is voluntary. The principal purposes for the collection of this information are: (1) to conduct contact tracing, (2) to evaluate and improve contact tracing in the state, and (3) to do other activities related to monitoring and control of COVID-19 in the community.

According to California law, the information collected shall be confidential and shall be collected in a manner that protects your privacy. However, it could be disclosed when there is a judicial order, judge-signed warrant, or when requested by the California State Auditor.

All individuals have the right to access records containing their personal information, which are maintained by the California Department of Public Health. To get this information, or for more information about this program, please contact the Division Chief of the Division of Communicable Disease Control at the address above.

Virtual Assistant Legal Policies (Terms & Conditions)

Communication with the Virtual Assistant is secure and only accessed through the secure link that is different for each user. All information shared with the Virtual Assistant is kept confidential and protected by California's strict privacy laws. The full privacy policy is also available on this website.

Message and data rates may apply. Message frequency varies. Reply STOP at any time to cancel. Reply HELP at any time for customer support information. Carriers are not liable for delayed or undelivered messages.

The Virtual Assistant is not intended to be a substitute for professional medical advice, diagnosis, or treatment. If you develop symptoms or the status of your health changes, please contact your local health provider. If you have an emergency and need immediate medical care, please dial 9-1-1. The personalized secure link provided to you is intended to be used for your health situation only. Please do not share your link with anyone else or use it to get COVID-19-related information for anyone else.

The Virtual Assistant is only available to individuals who are over the age of 18.

Please be aware that personal health information will be sent to your phone through the Virtual Assistant. There is a risk that others could see this information if you have a shared phone.

For customer support, contact your local public health department. This service is a part of the California Connected program.