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Updated May 24, 2022:
Are you eligible for a booster, second booster, or third dose of the COVID-19 vaccine? This page offers clarification on who is eligible to receive an additional dose of vaccine and the difference between third doses and booster shots.
Ready to receive a booster or a third dose? Click the button below to find your nearest vaccine site.
What is the Difference Between a 3rd Dose and a Booster?
Who can get a booster?
In California, almost everyone is eligible to receive a booster dose.
You are eligible for a COVID-19 booster if:
- You are 5 or older and:
- 5 months have passed since your second dose of Pfizer, or
- You are 18 or older and:
- 5 months have passed since your second dose of Moderna, or
- 2 months have passed since your first dose of Johnson & Johnson
The State of California's eligibility process allows for individuals to self-determine their risk of exposure.
Marin County Public Health strongly recommends you get a booster dose as soon possible if you meet California's eligibility and you are:
- Age 50 or older, OR
- Age 18+ who have underlying medical conditions, OR
- Age 18+ who live in long-term care settings, OR
- Age 18+ who work or live in high-risk settings
May 20, 2022: California Department of Public Health (CDPH) aligned with another recommendation from the FDA, CDC, and Western States Scientific Safety Review Workgroup to authorize a booster dose of the Pfizer COVID-19 for 5 to 11 year old's. Marin County Public Health has aligned with CDPH and now offers boosters for this new age group.
Second booster eligibility:
A second booster dose of the Moderna or Pfizer COVID-19 vaccine has been approved for certain groups.
The additional booster shot is for people who received their first booster more than four months ago and are:
- Age 50 & older
- Age 18 & older with moderate / severe immunosuppression
- Age 12-17 with moderate / severe immunosuppression (Pfizer booster only)
Additionally, CDPH and CDC recommend anyone who received a primary vaccine and booster dose of Johnson & Johnson at least four months ago is eligible to receive an additional Pfizer or Moderna booster dose.
Examples of moderate or severe immunosuppression include people on chemotherapy or who have had a solid organ transplant, like a kidney transplant or heart transplant. This also includes people who have an immunodeficiency, have an advanced or untreated HIV infection, or are undergoing treatment with high-dose corticosteroids or other medications that suppress immune response.
Marin County Public Health is currently offering second booster doses by appointment only at select locations. If you meet these criteria, you can book your shot at My Turn. Are you newly eligible for a second booster dose? Contact your doctor or medical provider to see if getting an additional booster dose is right for you.
January 10, 2022: California Department of Public Health (CDPH) aligned with another recommendation from the CDC and FDA to reduce the window of eligibility for Moderna booster doses from 6 months to 5 months after completion of an initial Moderna vaccine series.
January 6, 2022: CDPH implemented the use of a Pfizer booster in individuals aged 12 to 15. This change went into effect after the FDA expanded authorization for the use of a Pfizer booster in individuals aged 12 to 15 on January 3, followed by recommendations by the CDC's Advisory Committee on Immunization Practices (ACIP) on January 5 and the Western States Scientific and Safety Review Workgroup (WSSSRW) on January 6.
How do I know if I have a qualifying underlying health condition?
Marin County Public Health uses the CDC's designations for identifying underlying health conditions. Examples of underlying health conditions include (but is not limited to) cancer, chronic kidney disease, diabetes, asthma, mental health diagnoses and obesity. However, the definition also extends to those that have been impacted by systemic health and social inequities, recognizing that inequality is also a contribution to negative health outcomes, and a booster dose may be beneficial to those impacted.
What defines a high-risk job?
In line with the CDC, high-risk jobs are defined as:
- First responders (healthcare workers, firefighters, police, congregate care staff)
- Education staff (teachers, support staff, daycare workers)
- Food and agriculture workers
- Manufacturing workers
- Corrections workers
- U.S. Postal Service workers
- Public transit workers
- Grocery store workers
Can I get a booster dose from a different manufacturer than my original vaccine?
Yes, state and federal vaccine regulatory agencies have approved use of the vaccines as a “mix and match” booster option. This means your single booster dose could be a different brand than your original vaccine series. Eligibility and booster dose timing is based on the brand of your original vaccine series. For example,
- If you originally received Johnson & Johnson, you may receive a Pfizer, Moderna (half dose), or Johnson & Johnson booster vaccine two months after your original dose.
- If you originally received Moderna or Pfizer and you meet eligibility for a booster, you may receive a Pfizer, Moderna (half dose) or Johnson & Johnson booster vaccine six months after completing your original vaccine series.
Who qualifies for a third dose?
A third dose of the Pfizer or Moderna COVID-19 vaccine is recommended by CDC for severely immunocompromised people who received their second dose at least 28 days ago, and have:
- Been receiving active cancer treatment for tumors or cancers of the blood
- Received an organ transplant and are taking medicine to suppress the immune system
- Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
- Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
- Advanced or untreated HIV infection
- Active treatment with high-dose corticosteroids or other medications that may suppress your immune response
Why are third doses limited to such a small group?
The CDC estimates that about 2.7% of the population of the United States is immunocompromised, including organ transplant recipients, people undergoing cancer treatment, and those with other immunodeficiencies. In Marin County, this represents approximately 10,000 people. This population is more likely to become infected with COVID-19, even after vaccination, compared with similarly vaccinated but otherwise healthy individuals. They are also more likely to become severely ill due to COVID-19.
Where can I access a booster or third dose?
Start with your health care provider. Your doctor will know whether you will benefit from a booster shot or third dose. Providers who offer regular vaccinations (e.g., flu, pneumovax, shingles) should provide eligible patients with COVID-19 booster vaccines as capacity allows.
Most vaccine providers in Marin County are providing third doses and boosters to people who are eligible. Vaccine providers include:
- Healthcare Providers (your personal doctor or physician)
- Medical Clinics
- Marin County Public Health pop-up vaccine sites
- Marin County Public Health 12 & over clinic inside Northgate Mall
- Retail Pharmacies
Due to high demand, appointments are required by most providers for third doses and booster shots. Not all providers offer drop-in vaccinations: walk-ups are available on a very limited basis as supply allows, and may not be available at all locations. COVID-19 vaccine brand (e.g., Moderna, Pfizer, Johnson & Johnson) availability will vary by location. Verify that a provider offers the booster or third dose brand that you are seeking prior to walking-in or making an appointment. Online screening tools for retail pharmacies may not immediately reflect California's new booster dose eligibility: consider a walk-in appointment or seeking a vaccine from another location.
More Information and Frequently Asked Questions
Stay up-to-date with the latest information about booster and third doses by following the latest information on the California Department of Public Health (CDPH) and CDC websites, and Marin County Public Health (MCPH) COVID-19 Booster FAQs .
- MCPH: Booster FAQs
- COVID-19 Vaccine Booster Questions & Answers (ca.gov)
- CDC: Booster Shot Information & FAQs
- CDPH: Booster shots and additional dose information
- CDPH: Third Dose Frequently Asked Questions
- CDPH Urges Eligible Californians to get COVID-19 Booster Vaccine