Contact Tracing 101

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What is Contact Tracing?
How Does Contact Tracing Work?
Frequently Asked Questions

*Last updated: October 5, 2021

What is Contact Tracing?

The Baltimore City Health Department uses contact tracing to slow the spread of COVID-19 in Baltimore City.

With contact tracing, we

  1. Keep people from getting infected with COVID-19
  2. Reduce the number of people needing to go to the hospital with COVID-19  
  3. Keep people from dying from COVID-19

Contact tracing and isolation (staying home and away from others) are KEY TOOLS. Along with vaccines, mask- wearing and washing your hands, they help slow down the spread of disease, make sure our hospitals do not have more patients with COVID-19 than they can care for, and protect our families and our communities.

Together, we can protect each other. If we call you about COVID-19, you have the power to stop the spread.  By helping us reach others who may be infected, you could help save the lives of friends, family, and others in our communities.

What are the symptoms of COVID-19?

Symptoms may appear 2-14 days after exposure to the virus. People with these symptoms may have COVID-19:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

It can be difficult to tell the difference between COVID-19, a cold, allergies, and the flu just based on symptoms. Testing is needed to tell the difference between these conditions.

What should I do if I develop COVID-19 symptoms? 

  • If you have symptoms of COVID-19 you should get tested. While waiting for test results, you should stay home and away from others, including those living in your home, as much as possible. When it’s not possible to stay away from others, wear a mask.  

Who should get tested for COVID-19?

  • People who have symptoms of COVID-19
  • People who have had close contact with someone with confirmed COVID-19
    • Unvaccinated close contacts: Should get tested as soon as they learn they are a close contact with someone with COVID, and again at 5-7 days after their last exposure to the person who has COVID. If they develop symptoms, they should isolate and get tested immediately.
    • Fully vaccinated close contacts: Should get tested 3-5 days following known exposure to someone with COVID-19 and wear a mask in public indoor settings for 14 days or until they receive a negative test result
    • People who have tested positive for COVID-19 in the past 3 months and recovered do not need to get tested following exposure as long as they do not develop new symptoms
  • Unvaccinated people who have taken part in activities that put them at higher risk for COVID-19 because they cannot physically distance themselves, such as travel, attending large social or mass gatherings, or being in crowded or poorly ventilated settings
  • People who have been referred get tested by their healthcare provider or health department.
  • People who are traveling may also need to get tested 

More information can be found here on the CDC's COVID-19 Testing: What You Need to Know web page.

Where can I get Tested?

Vaccines, Breakthrough Cases, and Indoor Vs. Outdoor Disease Transmission

  • The COVID-19 vaccine is highly effective in preventing severe diseases, including hospitalization and death from COVID.
  •  Individuals that are vaccinated can still contract coronavirus, but are less likely to develop symptoms or have severe disease.
  • No vaccine is 100% effective and vaccinated individuals can get infected with COVID-19, known as a breakthrough case.
  •  Since January 2021 11.5% of COVID cases in Maryland are in fully vaccinated individuals.
  • There is emerging evidence that vaccinated individuals are less infectious and therefore less likely to spread the virus to others compared to unvaccinated individuals.
  • COVID-19 continues to circulate, especially among unvaccinated individuals. To reduce the spread of COVID-19 we continue to recommend that unvaccinated or partially vaccinated individuals wear a mask in all public areas - indoors and outdoors
  •  COVID spreads more easily indoors compared to outdoors. Generally, outside activities have a lower risk of COVID transmission due to increased ventilation and people being more spread out. Therefore, individuals are less likely to be exposed to COVID in outdoor settings.
  • Baltimore City mandates that unvaccinated and partially vaccinated individuals wear a mask in indoor and outdoor public spaces.  Unvaccinated or partially vaccinated individuals are more likely to transmit COVID to others.
  • In the setting of the Delta variant and current high community transmission across the United States, Maryland, and Baltimore City the best defense to reduce the spread of COVID is multi-layered - we must get vaccinated, continue to mask, social distance, and wash our hands frequently.

How Does Contact Tracing Work?

Find more info about Contact Tracing Steps here.

Step 1: The Health Department learns that someone has tested positive for COVID-19.

By Maryland and U.S. law, the Local Health Department must be told when someone tests positive for diseases, such as COVID-19, that spread among people. This law helps the local health department protect the community.

Doctors and medical labs must share COVID-19 test results with the Health Department.

The Health Department keeps all testing information, including results, confidential. The Health Department will not share your test results.

Step 2: The Health Department calls the person with COVID-19.

When a person tests positive for COVID-19, the health department will call them to:

  1. Make sure the person knows they tested positive for COVID-19
  2. Explain staying at home away from others (isolation)
  3. Determine when the person can stop isolation
    • The health department will let the person know when they can end isolation. A person should wait until they cannot spread COVID-19 to stop isolation.
  4. Find out who else might be at risk for COVID-19. These people are called close contacts.

Please make sure we have the RIGHT PHONE NUMBER! At the health department, we call people who have tested positive for COVID-19. We need patients, doctors, hospitals, and clinics to give us the correct phone numbers. Without the right phone number, we cannot reach people who test positive for COVID-19.

Step 3:  The Health Department will call close contacts to:

  • Tell them that they have been exposed to COVID-19 and the date they were exposed
  • Explain they might develop COVID-19 and to watch for symptoms
  • Explain that they should quarantine—stay away from others— to keep from spreading COVID-19
  • Explain how to quarantine and where to get help while in quarantine
  • Let them know where they can get the COVID-19 test

A person can spread COVID-19 for up to TWO DAYS before feeling ill. So, we will ask about close contacts during the time a person had symptoms of COVID-19 and the 48 hours before symptoms started.

Frequently Asked Questions

Who is a Close Contact?

Generally, close contact is anyone who was within 6 feet of an infected person for a total of 15 minutes or more over a 24-hour time period while outside or indoors. The 15-minute time period is cumulative over 24 hours. (For example, close contact for five minutes three times in one day is considered close contact.)

  • There may be different definitions of close contacts for certain settings, such as healthcare settings and schools.   
  • Generally, whether or not you are wearing a mask does not change if you are considered a close contact. It is important to remember that wearing a mask is important to decrease the transmission of COVID-19.
  • An infected person can spread COVID-19 starting from 2 days before they have any symptoms (or, if they are asymptomatic, 2 days before their COVID test was collected) until they meet the criteria for discontinuing home isolation

Close contacts include:

  • People who live in the same home
  • Co-workers who are closer than 6 feet of one another for more than 15 minutes. Examples include working, meeting, or eating together in the same room
  • Friends meeting together at a party or meal in a home or restaurant
  • Family members visiting each other’s homes

Close contacts do not include “casual contacts.” Casual contacts are people who were in the same place, such as grocery stores, but we're not closer than 6 feet to the person for more than 15 minutes. The health department will not ask about casual contacts.

The Health Department will ask a person with COVID-19 to list all their close contacts.

What does the Health Department do with information about my close contacts?

If we have a phone number, we will call the close contact to tell them they were exposed to COVID-19 and what they need to do (see Step 3). We do NOT tell them who gave us their name, at ANY time. That information is PRIVATE and very closely protected.

PLEASE STAY HOME if you are SICK, or have been in CONTACT with those who are sick. As businesses open again, we must stop the spread of COVID-19 to protect our families, friends, and communities.

How are close contacts identified?

Close contacts are identified from people who test positive for COVID and whose test results are reported to the health department. Once someone’s test result is reported to the health department, a contact tracer will call and ask the person who tested positive who their close contacts were during their infectious period until they are able to safely isolate themselves from others. If the person who tests positive names close contacts and provides their phone number to the contact tracer, the health department will reach out to the close contacts to notify them of their exposure. The health department does not share the name of the person who tested positive to close contact.

In order for close contacts to be notified, the following must occur:

  • Someone who has COVID is tested
  • Their test result is reported to the Health Department
  • They pick up the phone and answer the call from the contact tracer
  • They recall close contacts during their infectious period (as aided by the contact tracer)
  • They tell the contact tracer an accurate name and phone number of their close contact
  • The close contact picks up the phone when the contact tracer calls 

How will I be notified that I am a close contact and what should I expect? 

  • Individuals who are identified as close contacts and whose phone number has been provided to the health department will be called by contact tracers at the Maryland Department of Health or the county in which they reside.
    • When a contact tracer calls the caller ID will read “MD COVID” or the phone number (240) 466-4488 will appear on your screen. If you receive a contact tracing call from a different number and you wish to verify this person is calling from the State or local health department you may hang up and call back to the BCHD COVID-19 Call Center at 443-984-8650. 
    • MD COVID Alert: Close contacts can also be notified through MDH’s MD COVID alert.  This system uses exposure notifications technology to notify users who may have been exposed to an infected person, through cell phone applications. This can be helpful in situations when individuals might not know exactly who their close contacts are. Individuals must sign up for MD COVID Alert to receive notifications.
  • During the interview, contact tracers provide close contacts instructions on when to get tested and if and how long they should quarantine and any resources that may be available. 
  • Discussions with health department staff are confidential. This means that your personal and medical information will be kept private and only shared with those who need to know.
  • As an employer, Baltimore City also conducts contact tracing specifically for city employees who may have been exposed to COVID while at work, provided those who are COVID positive notify their supervisor and HR per city protocols. City employees who are identified as close contact by a co-worker will be notified, and provided instructions on when to get tested, where they can get tested, and if and how long to quarantine.

More information can be found on the Maryland State Government Coronavirus Site by clicking here.:

What Should I Do If I Have COVID-19?

If you are SICK with symptoms of COVID-19 OR you have tested positive for COVID-19,  stay home, away from work, and others.

Who needs to quarantine, and if so, for how long? 

  • Individuals who came in close contact with someone with COVID-19 and are unvaccinated or partially vaccinated are recommended to quarantine for 14 days after their last contact with some with COVID-19. 
    • In some situations, you may be eligible to shorten your quarantine period to 10 days or 7 days after receiving a negative test result on day 5 or after.
    • You may be required to extend your quarantine beyond 14 days if you continue to be exposed to someone with COVID-19 and need to continue to quarantine for up to 14 days after the individual is no longer infectious (e.g. a parent caring for a child with COVID-19).  
  • Individuals who came in close contact with someone with COVID-19 and are fully vaccinated or have tested positive for COVID-19 in the last 90 days do not need to quarantine unless they develop symptoms. They should monitor themselves for symptoms, and wear their mask in indoor settings for 14 days after their last exposure or until they test negative.
  • During quarantine you should: 
    • Stay at home
    • Not go to work or be in public spaces 
    • If possible, stay away from people you live with, especially people who are at higher risk of getting very sick from COVID-19. 
    • Watch for fever (100.4◦F), cough, shortness of breath, or other symptoms of COVID-19
    • Get tested if you develop symptoms
  • If you test positive - isolate and remain away from others, including family for 10 days, until your symptoms have improved and you have been fever-free for 24 hours, without taking any medication. You do not have to get a follow-up COVID test after your isolation period has ended.

What if the Health Department Calls Me?

Getting a call from the health department may worry you. But, please know that we call to help you and to protect our community. Here is what to expect when we call:

  1. We make sure that we are talking to the right person by asking you to confirm your name and other information.
  2. We ask about when your symptoms first started. This helps us know more about how COVID-19 is spread and who may be at risk.
  3. We ask about places you have been to recently – such as home, work, or time with family or friends. We ask about your work. This helps us know how to slow down the spread of COVID-19.
  4. We also ask about who may have been near you recently, and we ask for their contact information if you have it.  We will call the close contacts to tell them they might have been exposed to COVID-19. To keep your information private, we do NOT tell them who gave us their information or where they may have been exposed. This step is important to stop the spread of disease. We can only stop COVID-19 if those who are exposed remain away from others, even before they feel sick. At the health department, we will protect your privacy. Our staff members are trained to keep your information confidential.
  5. We will also explain about isolation, staying home, and being away from others for their protection. We will let you know where to get help with food, medicines, and other needs, while in isolation.

Masking for close contacts

  • Close contacts that are unvaccinated or partially vaccinated:  Recommended to wear a mask at all times - indoors and outdoors - during their quarantine period.
  • Close contacts that are fully vaccinated: Recommended to wear their mask in public indoor settings for 14 days after coming into contact with the COVID-positive individual, or until their test result is negative. 

What Do Employers Need To Know?

If you are an employer, please find information on contact tracing and job sites at the BCHD COVID-19 and Employers website.