COVID-19 Booster Shots

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The Centers for Disease Control and Prevention and U.S. Food and Drug Administration have authorized a third shot of the Pfizer-BioNTech COVID-19 vaccine (Comirnaty), Moderna and the Johnson & Johnson COVID-19 vaccine for most populations.

People age 18 and older who originally received the Moderna or Pfizer vaccine may get a booster dose approximately six months or more after they received their second dose of vaccine. People age 18 and older who originally received the Johnson & Johnson vaccine may get a booster dose approximately two months or more after their single dose. 

CDC also authorized a “mix and match” approach to booster doses. People may get a different type of vaccine for their booster than their original series. For example, if you received a Johnson & Johnson vaccine for your first dose, you may choose to get a booster dose of Pfizer, Moderna, or Johnson & Johnson.   


Who is eligible to receive a booster shot?

You should get a booster dose if you:

  • Are 18 or older and received your second dose of Pfizer or Moderna at least six months ago.
  • Received the Johnson & Johnson vaccine for your initial dose at least two months ago.

Because COVID-19 is spreading quickly throughout the state, Colorado is a high-risk place to live and work. Anyone who is 18 or older who would like a booster and is due for one should make a plan to get one. We encourage you to speak with your health care provider if you have questions about boosters.

Where can I get my booster shot?

Booster shots are available at local vaccine provider sites. Click here to find one in your area. It's a good idea to bring your Vaccine Card to your appointment, but no other identification or insurance is required. Booster shots, like all COVID-19 vaccines, are free.

Is the booster shot safe? Is it needed?

The CDC and FDA have authorized a third vaccine dose for the Pfizer vaccine and Moderna vaccine for most populations, and a second dose of the Johnson & Johnson vaccine for all populations, after analyzing safety and immune response in a subset of clinical trial participants as well as real-world data. To learn more about how the authorization process worked click here and here.

The available data suggest waning immunity in some populations who are fully vaccinated. The availability of these authorized boosters is important for continued protection against COVID-19 disease.

Why is a booster being recommended now?

As the science and the virus evolves, official policies and recommendations can and do change. Booster doses are common for many vaccines. The scientists and medical experts who developed the COVID-19 vaccines continue to closely watch for signs of waning immunity, how well the vaccines protect against new mutations of the virus, and how that data differs across age groups and risk factors.

Millions of Americans are now eligible for booster shots. Scientists and medical experts at the FDA and CDC continue to review data about booster doses for each COVID-19 vaccine separately, and new recommendations may be issued at different times.


About Shots for Immunocompromised People

In response to the CDC signing and endorsing the Advisory Committee on Immunization Practices’ (ACIP) recommendation, the state of Colorado advises vaccination providers across the state to offer an additional dose of the Pfizer-BioNTech COVID-19 Vaccine or the Moderna COVID-19 Vaccine to moderately to severely immunocompromised Coloradans. This recommendation pertains to immunocompromised persons who received the mRNA two-dose vaccine series. 

Answers to common questions are listed below.

Am I considered immunocompromised?

The CDC’s Advisory Committee on Immunization Practices (ACIP) recommends people whose immune systems are moderately to severely compromised receive an additional dose of mRNA COVID-19 vaccine at least four weeks (28 days) after their second dose.

The additional shots are for people who received an mRNA vaccine — those made by Pfizer or Moderna.

People who are recommended to receive an additional dose include people who 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 two 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 drugs that may suppress your immune response.

Why do immunocompromised people need a booster shot?

People who have a moderately to severely compromised immune system may benefit from an additional dose of vaccine to make sure they have enough protection against COVID-19. Studies show that some people who are immunocompromised don’t build adequate levels of protection after receiving two doses of mRNA vaccines.

Which brand of vaccine should I receive?

The additional dose should be the same vaccine product as the first two doses. However, an alternate mRNA dose can be used if that vaccine is not available. People should not receive more than three mRNA COVID-19 vaccine doses.

When can I receive my third dose?

Coloradans who need an additional dose should be able to access them immediately at enrolled state and federal vaccine providers.

Will I need to pay or have insurance?

Additional doses are free. No ID, insurance, or proof of medical history is required to receive an additional dose. Coloradans may self-report their immunocompromising conditions to vaccine providers.