Information About Boosters and Additional Doses

What’s the difference between a booster and additional dose?

An additional dose is recommended for people who do not have an adequate response to their original vaccine series due to conditions or medications that suppress their immune system and for people who received the Johnson and Johnson vaccine for their primary series. Getting an additional dose can help these individuals make more antibodies and protect against COVID-19.

A booster refers to another dose of a vaccine that is given to someone who built enough protection after vaccination, but then that protection decreased over time (this is called waning immunity).

So far, reactions reported after the additional dose or booster were similar to that of the two-dose series: fatigue and pain at injection site were the most commonly reported side effects, and overall, most symptoms were mild to moderate. However, as with the two-dose series, serious side effects are rare, but may occur.

Who is eligible for a booster dose of the COVID-19 vaccine?

The CDC has recommended booster doses  for all people aged 12 and older, even if they were aged 11 at the time of the primary series  to increase protection against infection with COVID-19.  Visit the CDC website for the most current eligibility guidelines. An mRNA COVID-19 vaccine is preferred over the Janssen COVID-19 Vaccine for booster vaccination

Those age 12 and older who were vaccinated outside the United States with a WHO emergency use listing vaccine or a heterologous series with WHO-EUL and FDA approved non-U.S. vaccine series are eligible for a booster. More information here about non-U.S. vaccine series. Call the CCRL at 203-432-6604, if you need additional guidance. 

Who is eligible for an additional dose of the COVID-19 vaccine?

The CDC recommends an additional dose for people who received Janssen COVID-19 Vaccine for their primary series and those who are moderately to severely immunocompromised with the following conditions: 

  • Active cancer treatment for cancers of the blood and for a solid tumor within one year of your initial mRNA COVID-19 vaccine series (including chemotherapy, hormonal therapy, immunotherapy, surgery and/or radiation therapy) 
  • Received an organ transplant and are taking medicine to suppress the immune system 
  • Received a stem cell transplant within the last 2 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 (or were taking at the time of your initial mRNA COVID-19 vaccine series) with immune-suppressing medications, including high-dose corticosteroids (at least 20 mg of prednisone a day), chemotherapy, tumor necrosis factor (TNF) inhibitors, and other biologic agents that suppress the immune response 

Visit the CDC website for the most current eligibility guidelines for additional doses.

Self-schedule for an additional dose or booster through the Yale COVID-19 vaccine program

You will be asked to identify and confirm that you have one or more of the qualifying conditions at the time of scheduling. If you have questions about whether you are immunocompromised, please speak to your treating clinician.

If you have questions about the vaccine or need help scheduling your vaccine, please call the Campus COVID Resource Line at 203-432-6604 for assistance.

Updated March 23, 2022