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UPDATE: COVID-19 Vaccine Booster Doses vs. Additional Doses: What’s the Difference?

November 22, 2021

Author

Pader Moua, MPH
Policy Analyst
501-526-2244
PMoua@achi.net

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LATEST UPDATE:

On Nov. 19, the Centers for Disease Control and Prevention (CDC) expanded eligibility for COVID-19 booster doses to include all adults age 18 or older who received the Pfizer or Moderna vaccines (adults who had received the one-dose Johnson & Johnson vaccine were already eligible). This includes individuals who received different mRNA vaccine doses for their two-dose primary series. Our infographic has been updated based on the latest CDC recommendations to include the expanded booster shot eligibility as well as clarify that children ages 5 to 11 are not recommended to receive an additional dose.

10/28 UPDATE:

(Original post published Oct. 11, 2021)

COVID-19 booster shots and additional doses are now available for certain individuals. This has led some people to ask: What’s the difference? Our updated infographic explains.

On Oct. 21, the Centers for Disease Control and Prevention announced that certain recipients of the Moderna or Johnson & Johnson vaccines are now authorized to receive booster doses. Previously, only certain recipients of the Pfizer vaccine were authorized for booster doses.

Booster doses are authorized for certain recipients of the Pfizer or Moderna vaccines who completed their two-dose primary series at least six months ago and recipients of the Johnson & Johnson vaccine who are age 18 or older and completed their one-dose primary series at least two months ago. These doses are meant to provide additional protection for certain vulnerable populations and people who live or work in high-risk settings, as protection against COVID-19 may wane over time. Eligible recipients of the Pfizer or Moderna vaccines include those who are:

Individuals eligible for booster doses are also newly authorized to “mix and match” their booster dose using any of the three vaccines. This means they can choose the same vaccine as the primary series for their booster dose or choose a different vaccine. Unlike the Pfizer vaccine booster, which is a full dose, the Moderna vaccine booster is a half dose.   

Additional doses are authorized for recipients of the Pfizer and Moderna vaccines who have moderate-to-severe immunocompromised systems. These individuals can receive their additional dose at least 28 days after their two-dose primary series. Third doses are “intended to improve immunocompromised people’s response to their initial vaccine series.” Individuals eligible for a third dose include those 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 or Wiskott-Aldrich syndrome
  • advanced or untreated HIV infection
  • active treatment with high-dose corticosteroids or other drugs that may suppress their immune response

According to CDC guidance updated on Oct. 25, immunocompromised individuals who received the one-dose Johnson & Johnson primary series are eligible for a booster. Additionally, immunocompromised individuals who completed their two-dose primary series and received an additional dose of the Pfizer or Moderna vaccines may receive a booster six months after the additional dose. 

As of Thursday, Oct. 28, more than 135,000 Arkansans had received either a booster or an additional dose of the COVID-19 vaccine.