Alameda County Health Care Services Public Health Department

Isolation & Quarantine

Tested positive for COVID-19 or are a close contact of someone who did? Stay home to protect others.

Isolation keeps someone who is sick or tested positive for COVID-19 without symptoms away from others, even in their own home.

Home Isolation Guidance

Note:
The guidelines below reflect the most recent recommendations by CDC and CDPH (California Department of Public Health). They are available to you as an option, though risk of transmission may exist past 5 days. Isolating away from others for 10 days continues to be the safest option.

Persons Who Test Positive for COVID-19 (Isolation)

Recommended Action

If you have tested positive for COVID, you should isolate regardless of vaccination status or lack of symptoms

Stay home for at least 5 days.
Isolation can end after Day 5 if:

Symptoms are not present, or are mild and improving; AND
You are fever-free for 24 hours (without the use of fever-reducing medication).

If fever is present, isolation should continue until fever has resolved for at least 24 hours (without the use of fever-reducing medications, such as Tylenol/ibuprofen).
If other symptoms are not resolving, continue to isolate until symptoms are resolving or until after Day 10.
Wear a well-fitting mask around others for a total of 10 days, especially in indoor settings (see masking guidance below for additional information).
Contact your medical provider to see if you are at high risk for severe COVID disease and qualify for COVID treatments. You can learn more at https://covid-19.acgov.org/antibody-treatment

Masking Guidance:
Wearing a well-fitting mask is essential to protecting others through 10 days after your infection starts. For information on how to use masks most effectively, please refer to Get the Most out of Masking.

After ending isolation, persons may remove their mask sooner than Day 10 with two sequential negative tests (antigen test preferred), 24 hours apart.
Note: this will only affect the general public but cannot be applied to covered workers due to current language in CalOSHA regulations.

Guidance & Resource Packet: Isolation & Close Contacts (3.16.23): English
(Translations coming soon)

Quarantine keeps a person who was in close contact with someone who has COVID-19 away from others.

In line with recommendations from California Department of Public Health, most individuals do not have to quarantine after an exposure to COVID-19. There are, however, steps people should take to reduce the risk of spread.

Close Contact & Quarantine Guidance

Note:

Changing conditions mean that quarantine (keeping exposed – but not yet symptomatic or known to be infected – individuals away from others) is now a less effective strategy for preventing the spread of COVID-19 outside of high-risk settings. The virus that causes COVID-19 has evolved to have a shorter incubation period (the time between exposure and becoming ill). The virus can also spread from person to person at greater distances, especially indoors. Tools such as testing and mask-wearing are still very important after an exposure to someone with COVID-19. If you develop symptoms, isolate immediately and test for COVID-19.

Staying up to date on vaccination continues to be the best way to prevent hospitalization or death from COVID-19. If someone who is at high-risk for severe disease becomes infected, there are prescription pills (and outpatient antibody infusions) available that provide protection against hospitalization and death. The costs of these medications are free, but they must be started within a few days after symptoms begin. Don’t wait until symptoms get worse.

If you believe you have been exposed to COVID-19, you are strongly encouraged to take the actions listed below to protect yourself and others. While you do not need to quarantine, consider avoiding people at high-risk for severe COVID-19 disease for 10 days such as: older adults, people living with chronic conditions, those with conditions that weaken their immune system, and people who are unvaccinated.

Persons Who Have Been Exposed to COVID-19 (Close Contact)

Recommended Action

If you have been exposed to another person who has COVID-19, you do NOT need to quarantine. If you have symptoms, please test immediately and follow isolation guidance if positive.

Exposed:

In indoor spaces 400,000 or fewer cubic feet per floor (such as a home, clinic waiting room, airplane etc.), a close contact is defined as sharing the same indoor airspace for a cumulative total of 15 minutes or more over a 24-hour period (for example, three separate 5-minute exposures for a total of 15 minutes) during an infected person's (confirmed by COVID-19 test or clinical diagnosis) infectious period.
In large indoor spaces greater than 400,000 cubic feet per floor (such as open-floor-plan offices, warehouses, large retail stores, manufacturing, or food processing facilities), a close contact is defined as being within 6 feet of the infected person for a cumulative total of 15 minutes or more over a 24-hour period during the infected person's infectious period

A person who has COVID-19 can start to spread the virus 2 days before they start to develop symptoms (or 2 days before their positive test was taken, if they never develop symptoms)

Take a COVID-19 test 3 to 5 days after being exposed or right away if you have symptoms.
Wear a well-fitting mask around others for a total of 10 days, especially in indoor settings (see masking guidance below for additional information).
Monitor yourself closely for any symptoms of illness for 10 days.

If you develop symptoms of illness, stay home and away from others until you can take a test for COVID-19. If your first test is negative, wait 24 to 48 hours and take another test since some people with COVID-19 don’t test positive right away.
If your COVID-19 test is positive, follow the isolation guidance listed above on this page

Persons who live, work, or regularly visit settings that are considered high-risk for severe COVID-19 spread or have vulnerable populations (example: nursing homes, jails, homeless shelters) should follow additional guidance from the facility. Links to specific guidance for those settings will also be provided below on this webpage

Masking Guidance:

Wearing a well-fitting mask is essential to protecting others through 10 days after your infection starts or after your last exposure. For information on how to use masks most effectively, please refer to Get the Most out of Masking.

Frequently Asked Questions: Exposure to COVID-19 and Close Contacts of Someone with COVID-19 Infection

A close contact is person believed to have been exposed to a virus by another person who is infected with that virus.

A person who is a close contact is at high risk for becoming infected with COVID-19. If they become infected, they might have symptoms or they might have no symptoms. If this happens, they could spread the virus to others, even without symptoms.

In most locations, a close contact is someone sharing the same indoor airspace (examples: home, clinic waiting room, airplane, office) 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) with someone infected with COVID-19.

In large indoor spaces greater than 400,000 cubic feet per floor (such as open-floor-plan offices, warehouses, large retail stores, manufacturing, or food processing facilities), a close contact is defined as being within 6 feet of the infected person for a cumulative total of 15 minutes or more over a 24-hour period during the infected person's infectious period.

Someone infected with COVID-19 is contagious two days before their first symptoms began. If the person with COVID-19 does not have symptoms, they are contagious two days prior to taking their COVID-19 test. A person is not considered contagious after they finish isolation (see section above on this page).

Except for healthcare or correction facility employees wearing proper personal protective equipment (PPE), you are you are still considered exposed even if you were wearing a mask during close contact.

In most circumstances, a close contact does not need to quarantine.

They should closely monitor themselves for any symptoms of illness in the following 10 days.

They are strongly encouraged to take a COVID-19 test between 3 to 5 days after they were exposed to a person infected with COVID-19, even if they never develop symptoms.

They are strongly encouraged to wear a high-quality, well-fitted mask for 10 days after they were last exposed to a person infected with COVID-19.

This person should immediately isolate at home and avoid others. They should do this until they have ability to take a COVID-19 test or speak with their healthcare provider. If the test is positive, they should continue to follow isolation instructions.

If the first antigen test after developing symptoms is negative, they should wait 24 to 48 hours and take a second antigen test to confirm they are still negative. A negative PCR test does not need to be confirmed.

If your symptoms worsen, follow up with a healthcare provider. If you have trouble breathing, call 911 or seek immediate emergency care.

Follow same guidance as outlined above, including monitoring for any symptoms of COVID-19. Wear a mask starting as soon as you are exposed and for ten days following your last date of exposure to the infected person (likely the last day of that person’s isolation period).

Ideally, you might consider taking a COVID-19 test 3 to 5 days after the first day of exposure and taking another test 3 to 5 days after the final day of exposure to this person while they are contagious (this may likely be the final day of their isolation period). You can also test more frequently during and after the days you are exposed.

Additional Considerations for Settings Considered High-Risk for Severe COVID-19 Spread

Please follow-up with your school to confirm your school’s guidance.

Comprehensive Guidance – California State Department of Public Health (CDPH)
Additional Resources – Alameda County Office of Education

For additional information regarding schools & childcare guidance, please see: https://covid-19.acgov.org/schools

Follow this guidanc from CDPH

Follow AFL 21-08 (or subsequent guidance from CDPH)
Healthcare providers in other settings: Follow CDC Guidance

Follow PIN 21-23-ASC (or subsequent guidance from CDSS)

Follow AFL 22-13 (or subsequent guidance from CDPH)

Definition of other high-risk settings (CDPH): A high-risk setting is one in which transmission risk is high (e.g., setting with a large number of persons who may not receive the full protection from vaccination due to co-existing medical conditions), and populations at risk of more serious COVID-19 disease consequences including hospitalization, severe illness, and death.
Employees and residents in these setting should follow recommendations from State Guidance

Follow recommendations (currently Page 3) of ACPHD Health Officer Order for Quarantine

In circumstances where State or Federal laws apply (including workplace safety regulations), Alameda County guidance, recommendations, and Health Officer Orders do not supersede, override, or modify those laws.

Resources

COVID-19 Treatments and Medicine:

If you have or think you have COVID-19, there are prescription pills (and outpatient antibody infusions) available that can help reduce symptoms. They provide protection from hospitalization and death from COVID-19. The costs of these medications are free, but they must be started within a few days after symptoms begin. Don’t wait until symptoms get worse before talking with a healthcare provider.

Please see our page on medications and treatment for COVID-19.
If you have questions about COVID treatment options, please contact our Treatment Inquiries Line (510-268-2101 | ncov@acgov.org): English | Spanish | Traditional Chinese

Home Isolation and Close Contact Guidance Packets

Please follow the isolation and close contact guidance in the packet below for people who have tested positive for COVID-19 and their household or close contacts. The packet also includes resources. Note that you may be contacted by a member of the contact tracing team.

Home Isolation and Close Contact Guidance Packets: (3/16/2023) English
More languages coming soon!

Travel Guidance

CDC COVID-19 Travel Guidance (CDC)

Guidance

COVID-19 Testing

Contact Tracing

Legitimate Contact

Isolation keeps someone who is sick or tested positive for COVID-19 without symptoms away from others, even in their own home.

Home Isolation Guidance

Persons Who Test Positive for COVID-19 (Isolation)

Recommended Action

Close Contact & Quarantine Guidance

Persons Who Have Been Exposed to COVID-19 (Close Contact)

Recommended Action

Frequently Asked Questions: Exposure to COVID-19 and Close Contacts of Someone with COVID-19 Infection

What does close contact mean?

Who is a close contact?

I was wearing a mask or the individual with COVID-19 was wearing a mask while I was exposed? Should I take action?

What actions should someone who is a close contact take?

What should a close contact do if they develop COVID symptoms in the days following an exposure to someone with COVID-19?

What should a close contact do if they cannot separate from someone infected with COVID-19 (such as sharing a living space)?

Additional Considerations for Settings Considered High-Risk for Severe COVID-19 Spread

K-12 Students

Childcare and Preschool Programs

Employees of Acute Care Hospitals, Psychiatric Hospitals, Skilled Nursing Facilities, and EMS

Adult and Senior Care Licensees

Residents of Skilled Nursing Facilities

Employees and Residents in Other High-Risk Settings

Employees and Residents of Correctional and Detention Facilities

Note on Other State or Federal Laws (Current or Future)

Resources

COVID-19 Treatments and Medicine:

Home Isolation and Close Contact Guidance Packets

Travel Guidance