A booster shot is an additional dose of a vaccine. It’s given to someone whose immune response from their last dose has weakened over time. For example, you’ve likely had a booster shot of a tetanus vaccine as part of your regular immunizations.
By getting a booster shot, you remind your body how to fight a disease. And your immune system gears up to protect you if you are exposed to that disease.
Booster shots for COVID-19
The Food and Drug Administration (FDA) has authorized booster doses for all three COVID-19 vaccines available in the U.S. The booster shots are not new vaccines. They refer to an additional dose of the existing COVID-19 vaccines.
You can find out who is eligible for booster shots based on which vaccine you got to complete your initial series. A completed series means two doses of an mRNA vaccine (Moderna or Pfizer) or one dose of Janssen/J&J.
If you completed your initial COVID-19 vaccine series with Moderna or Pfizer (Comirnaty)
The Centers for Disease Control and Prevention (CDC) recommends that the following groups SHOULD get an additional booster COVID-19 vaccine six months after completing the first two doses. These groups are:
- People 50 years old and older
- People 18 and older who live in long-term care
The CDC advises that anyone age 18 and older may choose to get the booster shot six months or more after completing the first two doses, depending on their individual risks.
If you completed your initial COVID-19 vaccine with Janssen/J&J
Two or more months after completing the initial dose, the CDC recommends booster doses for people who are 18 and older.
Can I mix and match COVID-19 vaccine brands for my booster shot?
If you’re getting an mRNA vaccine, the first two doses in your initial series must be the same vaccine brand. After you’ve completed your initial vaccine series – one dose for Janssen/J&J, two doses for Moderna or Pfizer – you can get a booster shot of a different brand if desired.
Please note, we at Mercy Health can’t guarantee a specific brand at a specific location, since our supply of vaccine arrives weekly and varies based on what is given to us from the Department of Health. However, if you have a strong brand preference, please let the clinical staff know when you arrive for your vaccine. We will do our best to accommodate your preferences.
What if I’m immunocompromised?
The CDC recommends that people who have weakened immune systems get an additional mRNA COVID-19 vaccine shot at least 28 days (four weeks) after completing their initial series. This applies to people with moderately to severely compromised immune systems due to a medical condition or taking medications to suppress the immune system.
This includes 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 CAR-T-cell or hematopoietic stem cell transplant within the last two years or are taking medicine to suppress the immune system
- Moderate or severe primary immunodeficiency (some examples include DiGeorge syndrome and Wiskott-Aldrich syndrome)
- Advanced or untreated HIV infection
- Active treatment with high-dose corticosteroids or other drugs that may suppress your immune system
Call the Mercy Health vaccine hotline at 866-624-0366. Representatives are available Monday through Friday from 8 a.m. to 5 p.m. EST and you can schedule an appointment or to get additional information about our facilities that are offering the COVID-19 vaccine.
Read more information about the COVID-19 vaccines.