COVID-19 Vaccine: Third Dose versus Booster

posted by Colette Rossiter on Tuesday, October 12, 2021

Booster dose, third dose, or additional dose. What’s the difference? If you’re confused, you’re not alone. Let’s break down the differences between who should receive the third additional dose and who should get a booster of the COVID-19 vaccine.

third/additional dose of an mRNA COVID-19 vaccine such as Moderna or Pfizer is recommended for some people with weakened immune systems, such as those who have had an organ transplant or those receiving cancer treatment. People with weakened immune systems may not have built the same level of immunity to the two-dose vaccine series compared to people who are not immune-compromised. So this additional dose should improve the response their immune system has to their initial vaccine series.

This third dose should be given at least 28 days after a second dose of an mRNA COVID-19 vaccine such as Pfizer or Moderna. The additional dose should be the same brand as the other two vaccine doses given.

booster dose is given for a different reason. Many vaccines have waning protection over time and need a boost to increase that protection again. Studies have found that to be a potential issue with COVID-19 vaccines, especially among our 65 and older population and other specific at-risk groups such as residents in long-term care settings and people ages 50 to 64 who have underlying medical conditions, such as cancer, diabetes and heart disease. A booster dose is also available to people ages 18 to 49 with underlying medical conditions and people ages 18 to 64 who have a job that puts them at increased risk of being exposed to COVID-19.

It is important to note that these recommendations for booster doses are ONLY for individuals who originally received the 2-dose series of the Pfizer COVID-19 vaccine. The booster dose should be given at least six months after the second dose of the Pfizer vaccine. 

Recommendations about booster doses for people who received the Moderna or Johnson & Johnson COVID-19 vaccine have not been made yet. Just a reminder that Moderna was used at the vaccination clinics Clay County Public Health held at the Clay County Events Center in February and March of this year. The clinics that public health held at Spencer Community Schools used Pfizer.

Check your vaccination card to determine which vaccine you received. Pfizer and Moderna vaccines are readily available locally through your healthcare provider, public health department or your local pharmacy.

dose vs booster

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About The Author

Colette Rossiter

Colette Rossiter, serves as manager for Spencer Hospital Community Health Services and Clay County Public Health. Colette has enjoyed the variety of responsibilities her nursing career has provided, yet has a passion for public health and safety.