COVID-19 Decision Trees

Changes to the definition of 'close contact' and its application in Cal/OSHA's Emergency Temporary Standards are reflected in the latest COVID-19 decision tree, updated June 28, 2022. The Spanish version is also current. If you are not seeing the most current version of the decision tree, please clear your internet cache, reload the page, and download the correct version. The decision tree will be updated as needed to reflect the latest public health guidance. Please check this page weekly to ensure you are using the latest version.

The e-Decision Tree (last updated April 11) is a digital representation of the San Diego County COVID-19 K-12 Decision Trees developed by the San Diego Supercomputer Center, UC San Diego in collaboration with the UC San Diego School of Medicine Division of Child and Community Health, and the San Diego County Office of Education. The e-Decision Tree has been updated to include the new “group tracing” option and is now able to calculate dates for testing and return for household exposures.

 

COVID-19 Decision Trees FAQ

 

English PDF (current)

Spanish PDF (current)

Online version is updated.

COMMON TERMS

1. What is the difference between quarantine and isolation?

Quarantine: When quarantine is used, people who have been identified as having been in close contact with someone with COVID-19 are required to quarantine away from others following their last contact with a person who had COVID-19.

Current guidance for COVID-19 does not require quarantine. Close contacts may continue normal activities if they remain asymptomatic and test negative on Day 3, 4, or 5 following their last exposure to a person who was contagious with COVID-19.

Isolation: People who have one or more of the symptoms associated with COVID-19 and/or have lab confirmed COVID-19 are required to isolate away from others while they may be contagious with COVID-19. A person:

  • With symptoms is considered to be contagious from 2 days before their symptoms began, to 5 to 10 days after.
  • Who has tested positive and does not have symptoms is considered contagious from 2 days before the date their first positive test sample was collected until 5 to 10 days after, if they remain asymptomatic.
  • Who tested positive while they were asymptomatic, and develops symptoms later, is considered contagious from 2 days before the first positive test sample was collected until 5 to 10 days after their symptoms began.

2. What counts as a close contact?

The current definition of close contact is sharing the same indoor airspace (e.g., home, clinic waiting room, airplane, etc.) for a cumulative total of 15 minutes or more over a 24-hour period (for example, three individual 5-minute exposures for a total of 15 minutes) during an infected person's (laboratory-confirmed or a clinical diagnosis) infectious period.

3. What is the difference between individual contact tracing and group tracing?

The terms “individual contact tracing” and “group tracing” have become slightly outdated.

Individual contact tracing for COVID-19 was based on the prior definition of close contact, which required identifying persons who were within 6 feet of a person who was contagious with COVID-19 for 15 minutes or more in a 24-hour period.

Based on the new definition, contact tracing is now focused on identifying the people who shared a common indoor airspace with a person who was contagious with COVID-19 for a total of 15 minutes or more in a 24-hour period.

Cal/OHSA’s emergency temporary standards and the CDPH guidance for schools both require that the school/employer notify close contacts of the date on which they were exposed, the need to test on Day 3, 4, or 5, following their last exposure, and of the requirement that the person isolate immediately if they develop symptoms.

For an employee close contact who does not have symptoms to remain at work, Cal/OSHA also requires that the employee provide evidence of a “verified” negative test result from a sample collected on Day 3, 4, or 5, following their last exposure, and that they wear a well-fitted mask indoors through Day 10.

Students who participate in testing on Day 3, 4, or 5 are permitted to remain in school and continue all school activities unless they develop symptoms or receive a positive test result. Schools are not required to track testing results and can rely on parents to report positives.

CONTACT TRACING AND CLOSE CONTACTS

4. Is contact tracing required for students in outdoor settings?

No. The definition of close contact is focused solely on indoor exposures.

5. Can a COVID-positive household member isolate themselves in a room in their home?

If the COVID-positive person is not able to isolate in a separate residence, the county’s home isolation instructions (translations) describe the specific requirements for isolation in a home occupied by others. If the person is able to comply with these instructions, quarantine of close contacts can begin when the COVID-19-positive person begins isolation.

6. Can a person attend school/work if they live with a person who is COVID-positive?

A person who lives with a household member who is COVID-positive may continue to attend school/work if they do not have symptoms. The person should test immediately upon learning that they are a close contact, and again on Day 3, 4, or 5, after the COVID-positive household member completes their isolation.

  • Student close contacts should be strongly encouraged to wear a mask indoors and around others through Day 10.
  • Employee close contacts are required to wear a mask indoors and around others through Day 10.
  • The person should isolate immediately if they develop symptoms or test positive.
  • Employers are required to verify negative test results.
  • Parents are expected to report positive test results to the school.
  • The positive household member should isolate themselves as described in question 5.

GROUP TRACING

7.Are people who are at least 14 days past completion of their primary COVID-19 vaccination series exempt from the requirement that they test on Day 3, 4, or 5?

No. Per the CDPH guidance people who shared a common airspace with a person who was contagious with COVID-19 for 15 minutes or more in a 24-hour period should test on Day 3, 4, or 5 to remain in school/work. This includes people who are fully vaccinated. However, those who have recovered from a prior lab-confirmed infection within the last 90 days should not test as long as they remain asymptomatic (see question 11).

8. Are students who are within 90 days of a prior lab-confirmed infection exempt from the requirement that they test on Day 3, 4, or 5?

Yes. Per the CDPH guidance, people who do not have symptoms and have recovered from a prior verified infection within the last 90 days do not need to test on Day 3, 4, or 5 following an exposure. If symptoms develop, the person should take an antigen test immediately and follow the instructions on the Symptom and Isolation Tree.

9. Are schools required to see evidence of negative test results from students who are required to test as part of an exposed group?

No. Schools are not required to track test results. Parents are expected to inform the school when their child tests positive or develops symptoms.

ISOLATION

10. How should schools manage eating and drinking for students who return from isolation before Day 11?

Students who return from isolation before Day 11 should be strongly encouraged to wear a mask that fits snugly over their nose and mouth indoors, and outside when they are within 6 feet of others on Days 6 through 10 from the onset of their symptoms. Schools should arrange for students who return from isolation before day 10 to eat and drink outside with physical distancing.

11. Can students who return from isolation before Day 11 participate in before- and after-school programs and activities on Days 6 through 10?

Children who are permitted to return to school from isolation before Day 11 may participate in before- and after-school expanded learning programs and child care, however they should be strongly encouraged to wear a mask that fits snugly over their nose and mouth indoors and when within 6 feet of others outside.

Participation in other after-school activities is not prohibited, but it’s also not advisable. People who are recovering from COVID-19 continue to be contagious for 10 days past the onset of their symptoms. A negative test on Day 5 indicates that the risk of transmission is lower, not eliminated.

12. Can student athletes who return from isolation before Day 11 practice and compete on Days 6 through 10 if they commit to wearing a mask as required?

It is not prohibited, but it’s also not advisable. A negative test result on Day 5 after symptom onset does not mean there is no virus in the person. It means that their viral load is low enough to reduce the chances of transmission while they are wearing a well-fitted mask. During exercise people exhale heavily, making their mask less effective, and increasing the chance of transmission. Limiting students who have returned from isolation to “walk-through” activities is advisable on Days 6 through 10.

13. Can musicians who return from isolation before Day 11 practice or perform on Days 6 through 10 if they use a bell cover over their instrument?

Students who return from isolation before Day 11 should be strongly encouraged to wear a mask that fits snugly over their nose and mouth, indoors and outside when they are within 6 feet of others.

TESTING

14. When is confirmation of an antigen test result necessary?

Positive antigen test results, including positive at-home test results, do not require confirmation with a PCR or other NAAT.

  • The decision tree for Asymptomatic Positive individuals has been updated, removing PCR confirmation as a means of verifying a positive antigen test result from a person who does not have symptoms.
  • For people with symptoms, a negative antigen result from a sample collected within 48 hours of symptom onset requires confirmation with a second test taken on the following day. An antigen, PCR, or other NAAT may be used for the confirmation test.

15. Why is it still necessary to confirm a negative antigen result from a symptomatic person?

A recent revision of the CDPH testing guidance suggested that antigen test results do not need confirmation provided that clinical assessment of the person’s symptoms was consistent with antigen test results, or modified if there was a “high-risk” exposure, but a list of concerning symptoms and high-risk exposures was not provided. In the absence of this information, the County of San Diego requires that schools continue to confirm negative findings when antigen tests are used with people in response to an onset of symptoms associated with symptoms. (Negative antigen results do not require confirmation being used to determine if a person can end isolation on days 6 – 10.)

16. Can at-home testing be used to satisfy testing requirements?

STUDENTS: Schools may accept the results of at-home testing for the same uses for which antigen tests are approved. Schools are encouraged to use a means described in the Over-The-Counter Tests Guidance to verify the results on tests administered at home. See the “What are best practices for verification of self-test results?” section for specific recommendations.

EMPLOYEES: Per Cal/OSHA, “an over-the-counter (OTC) COVID-19 test may be both self-administered and self-read if verification of the results, such as a time and date stamped photograph of the result or an OTC test that uses digital reporting with time and date stamped results, is provided." This guidance can be found in Cal/OSHA's May 7 FAQs under Testing.

STUDENTS and EMPLOYEES: When used for a person who has symptoms, the County of San Diego requires that a negative antigen test be confirmed by a follow-up test (antigen, PCR, or other NAAT) administered the following day, and that the person isolate pending the result of that test.

17. What are the requirements if a person tests positive but has no symptoms?

If the person remains asymptomatic, they are required to self-isolate for at least 5 days past the date on which the positive test was collected. To return to school, students should wear a mask that fits snugly over their nose and mouth, indoors and within 6 feet of others outside, on Days 6 through 10. Per Cal/OSHA, employees are required to mask through Day 10 when returning from isolation.

If the person develops symptoms, isolation must be extended until 10 days have passed since the onset of symptoms.

18. If a person who has symptoms is within 90 days of a previous verified COVID-19 diagnosis receives a negative antigen result, can they remain in school/work without PCR confirmation?

If a person who is within 90 days of the onset of symptoms from a prior COVID-19 diagnosis, has symptoms and is antigen negative, they may return to school when one of the following criteria has been met:

  • A second antigen test administered 12 hours or later after the initial antigen test. 
  • The person provides evidence of a verified diagnosis from a physician (MD, DO, PA or NP) of another illness that accounts for the symptoms. When this is the case, the person may return to school/work can when they have been free of fever for at least 24 hours without the use of fever-reducing medications, and their symptom are improving.
  • Otherwise, the person can return according to the criteria for return from isolation on Day 6 or 11.

VACCINATION STATUS

19. Has the standard for being fully vaccinated changed?

The term “fully vaccinated” has not been redefined, but some of the quarantine requirements for K-12 workers now consider whether a person has received a booster dose if they are eligible to receive one.

20. Do K-12 workers who are booster eligible and not boosted need to test weekly?

No. The weekly testing requirement is described in the state public health officer order (Aug. 11, 2021), which has not been updated since it was issued.

REQUIREMENTS VERSUS RECOMMENDATIONS

21. Why are some of the CDC’s recommendations not included in the decision trees?

While the Centers for Disease Control and Prevention (CDC) makes recommendations, the requirements for California schools are established by the CDPH and the school’s local health jurisdiction. The decision tree is based on the CDPH K-12 guidance and related FAQ, K-12 Testing Strategies, Cal/OSHA Emergency Temporary Standards, the local public health orders, pertinent executive orders, and answers received directly from the CDPH.

22. Is quarantine optional?

The CDPH no longer requires quarantine for asymptomatic close contacts. People who have been identified as close contacts may remain at school or work unless they develop symptoms, and are expected to test on Day 3, 4, or 5 following their last exposure to a person who was contagious with COVID-19.

  • For students, parents are expected to report positive test results to the school.
  • Employers must require evidence of a verified negative test result, or impose quarantine.
  • If a student or an employee develops one or more symptoms associated with COVID-19, they must isolate immediately and contact their school/employer.
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