COVID-19 Boosters

Photo of BandAids

The Centers for Disease Control and Prevention and U.S. Food and Drug Administration have authorized an updated COVID-19 booster, called a bivalent booster, that is designed to offer protection from the original COVID-19 virus and the omicron variant of the COVID-19 virus. Pfizer’s omicron vaccine dose is authorized for people aged 5 years and older. Moderna’s omicron vaccine dose is authorized for people aged 6 years and older. 

The CDC recommends that everyone who is eligible stay up-to-date on vaccinations by getting an updated booster dose at least 2 months after their last COVID-19 shot—either since their last booster dose, or since completing their primary series. Vaccine recipients can mix brands from the primary series. For example, a person who completed a Moderna primary series can receive a Pfizer updated booster.

The updated booster replaces most older boosters, but the following vaccines and boosters will still utilize the original doses:

  • Primary series doses. A primary series usually means two doses of Pfizer, Moderna, or Novavax, or one dose of Johnson & Johnson. People who are immunocompromised may receive up to three doses in their primary series. These vaccines are still the original formulations.

Are omicron doses available for children ages 6 months to 4 years?

Yes. Children aged 6 months through 4 years are now able to get the reformulated COVID-19 omicron vaccine in Colorado as a part of their three-dose primary series. Children in this age group are recommended to receive an omicron vaccine after receiving two doses of the original COVID-19 vaccines. The omicron vaccine must be the same brand as the vaccines they previously received.

  • Children 6 months through 5 years who have completed the two-dose Moderna primary vaccine series may receive a single Moderna omicron dose at least two months after their primary series completion.
  • Children 6 months through 4 years who have either not started or completed the three-dose Pfizer primary vaccine series may receive a single Pfizer omicron dose as the third dose in the Pfizer primary series.
  • Children 6 months through 4 years who already received the three-dose Pfizer primary vaccine series are not recommended to receive the omicron vaccine at this time. Data to support giving an omicron dose to this subset of children are expected in January.

Do I need an updated booster?

You should get an updated booster of either Moderna (age 6-plus) or Pfizer (age 5-plus) if:

  • You are age 5 or older and you have completed a primary series of COVID-19 vaccines. A primary series usually means two doses of Pfizer, Moderna, or Novavax, or one dose of Johnson & Johnson. People who are immunocompromised may receive up to three doses in their primary series.
  • You are age 5 or older you have previously received a third, fourth, or fifth dose — also known as booster doses.

People should get their omicron dose at least two months after their most recent dose of the COVID-19 vaccine and can wait three months after a recent COVID-19 infection. Learn more about omicron vaccine doses at

Where can I get my booster?

Vaccine sites are available. Click here to find one in your area. El Paso County Public Health Immunization Clinic is offering boosters; call 719-578-3199, option 5 to schedule. It's a good idea to bring your Vaccine Card to your appointment, but no other identification or insurance is required. Boosters, like all COVID-19 vaccines, are free.

Is the booster safe? Is it needed?

Pfizer and Moderna’s omicron doses use the same mRNA-based technology as the original versions of the COVID-19 vaccines. Hundreds of millions of people have safely received an mRNA COVID-19 vaccine in the U.S. In clinical studies, the new omicron doses successfully stimulated the immune system to produce antibodies. Antibodies are proteins in the blood that fight specific invaders in the body, like viruses.

Updated boosters are intended to provide optimal protection against the virus and address waning vaccine effectiveness over time.

Can I get the updated booster if I haven't been vaccinated yet?

No. The updated bivalent formula is in use only for COVID-19 booster doses, and not for initial vaccination. The best way to protect yourself from getting severely ill from COVID-19 is to get vaccinated. The CDC recommends that currently unvaccinated people get their primary series (the initial two doses of either Pfizer or Moderna, or one dose of the Novavax vaccine), and then wait at least two months to get the updated Pfizer or Moderna booster dose.

Can I mix and match my COVID-19 vaccine and booster?

Yes. Eligible individuals can get either the Pfizer or Moderna updated booster, regardless of whether their primary series or most recent dose was with Pfizer, Moderna, Novavax, or the Johnson & Johnson vaccine.

Can I receive a third shot of Novavax?

The FDA authorized and Centers for Disease Control recommend a third Novavax COVID-19 vaccine dose for adults. Adults aged 18 years and older who have not gotten any booster doses can receive a third Novavax dose six months after finishing their primary series of any authorized COVID-19 vaccine. This third dose is the same formulation and dosage as the doses in the Novavax primary series.

About Shots for Immunocompromised People

After completing the primary series, the Centers for Disease Control and prevention recommends that some moderately or severely immunocompromised people, should get an additional primary shot of the Pfizer COVID-19 Vaccine or the Moderna COVID-19 vaccine. People age 6 months and up who qualify may receive this additional primary dose. This recommendation pertains to immunocompromised persons who received the mRNA two-dose vaccine series. 

Everyone 5 years and older, including immunocompromised people, should get at least one booster. If you are eligible for an additional primary shot, you should get this dose first before you get a booster. Updated boosters are available for those age 5 and up.

Answers to common questions are listed below.

Am I considered moderately or severely immunocompromised?

People are considered to be moderately or severely immunocompromised (have a weakened immune system) due to several types of conditions and treatments. Examples include:

  • Tumors or cancers of the blood with or without active cancer treatment
  • Received an organ or islet transplant and are taking medicine to suppress the immune system
  • Received chimeric antigen receptor (CAR)-T-cell therapy (a treatment to help your immune system attach to and kill cancer cells) or received a stem cell transplant (within the last 2 years)
  • Moderate or severe primary immunodeficiency (such as common variable immunodeficiency disease, severe combined immunodeficiency, DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced or untreated HIV infection
  • Active treatment with high-dose corticosteroids or other drugs that may suppress the immune response
  • Talk to your healthcare provider about COVID-19 vaccination and your medical condition.

If you are moderately or severely immunocompromised or severely allergic to COVID-19 vaccines, you may be eligible for Evusheld, a medicine given every six months by your healthcare provider to help prevent you from getting COVID-19. Talk to your healthcare provider to find out if this option is right for you.

Why do immunocompromised people need an additional primary shot?

A third primary dose may prevent serious and possibly life-threatening COVID-19 in people who may not have responded to their two-dose mRNA COVID-19 vaccine primary series. People who are moderately or severely immunocompromised who have low or no protection after two doses of mRNA vaccines may have an improved immune response after a third primary dose of the same vaccine.

Can I mix and match vaccine brands for my additional primary shot?

No, vaccines used for the primary vaccination series should be the same product or brand. However, if the mRNA vaccine product given for the first two doses is not available or is unknown, either Pfizer-BioNTech or Moderna COVID-19 vaccine (mRNA COVID-19 vaccines) may be administered for the third primary dose.

When can I receive my third dose?

People can stay up to date with COVID-19 vaccination by completing a primary series and receiving the most recent booster dose recommended for them by CDC. The people you live or spend time with can help protect you and themselves by staying up to date on their COVID-19 vaccines too.

People who are immunocompromised should check the CDC's vaccine schedules here.

What is the difference between an additional primary shot and a booster shot?

For people who are immunocompromised, the third primary dose is the final dose of the primary series of an mRNA COVID-19 vaccine. Boosters are shots that enhance or restore protection against COVID-19, which may have decreased over time.

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.