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Additional Dose COVID Vaccine Frequently Asked Questions

Updated: November 15, 2021

The Department of Health is pleased that the FDA and CDC are taking steps to ensure individuals who are immunocompromised have the opportunity to receive another layer of protection against COVID-19. 

The Department is already working with vaccine providers on this important protection for these vulnerable Pennsylvanians. We are confident that the Commonwealth's strong vaccine supply and robust vaccine provider infrastructure will meet the needs of this critical population.

Who is eligible to get an additional dose of COVID-19 vaccine?

Currently, CDC is recommending that moderately to severely immunocompromised people receive an additional dose. CDC's recommendation includes people with a range of conditions, such as recipients of organ or stem cell transplants, people with advanced or untreated HIV infection, active recipients of treatment for cancer, people who are taking some medications that weaken the immune system, and others. A full list of conditions can be found on CDC's website.

Ultimately, a patient's clinical team is best able to assess the degree of altered immunocompetence and optimal timing of vaccination.

How many people in Pennsylvania are eligible to get the additional dose?

Based on the CDC's estimate that 2.7 percent of the population may be immunocompromised, the eligible population would be approximately 250,000 to 300,000 people in Pennsylvania.

When can I get an additional dose of the COVID-19 vaccine?

Immunocompromised individuals who are fully vaccinated with Pfizer and Moderna and are looking to receive this additional dose of the respective vaccine, should consult their health care provider before scheduling a vaccine appointment.

How long do I have to wait after receiving the 2nd dose to get the 3rd dose?

CDC recommends waiting at least 28 days after completion of your initial 2-dose vaccination before seeking the additional dose.

Where should I get my additional dose?

Immunocompromised individuals who are fully vaccinated with Pfizer and Moderna and are looking to receive this additional dose of the respective vaccine, should consult their health care provider before scheduling a vaccine appointment. To find a vaccine provider near you visit

Is the additional dose the same medicine as the earlier doses?


What is the difference between an "additional dose" and a "booster dose?"

An "additional dose" refers to people who are moderately to severely immunocompromised receiving an additional dose of an mRNA COVID-19 Vaccine (Pfizer-BioNTech or Moderna) at least 28 days after the completion of the initial mRNA COVID-19 vaccine series. This is because they may not have received adequate protection from their initial 2-dose vaccine series.

A "booster dose" is a supplemental vaccine dose given to people when the immune response to a primary vaccine series is likely to have waned over time. The need for and timing of a COVID-19 booster dose has not been established, and no booster doses are recommended at this time. CDC and FDA continue to review evidence and data as it is available about whether or when booster doses for the broader U.S. public may be needed, and will update guidance as more information becomes available.

View a graphic that shows the difference between additional and booster doses.

Why doesn't everyone need an additional dose?

The FDA has not recommended an additional dose for other individuals at this time. This recommendation helps to increase the likelihood this population is protected against COVID-19, especially as the more transmissible Delta variant spreads. CDC and FDA continue to review available evidence and data on whether or when booster doses for other populations, including seniors, may be needed. Available data right now show the vaccines continue to be strongly protective against severe illness and death caused by COVID-19.

If you are in close contact with immunocompromised people and are not yet fully vaccinated, you are encouraged to be vaccinated against COVID-19 now.

What happens if I get the additional dose even though I'm not immunocompromised?

It's important to note that an additional dose is only recommended for individuals who are moderately or severely immunocompromised — CDC does not recommend additional doses or booster shots for any other population at this time.

Will providers accept anyone who says they're immunocompromised to receive a third dose? Will people need to show a doctor's note/prescription or other documentation?

Immunocompromised individuals may discuss with their health care provider whether getting an additional dose is appropriate for them. If their health care provider is not at a site administering vaccines, these individuals can self-attest and receive the additional dose wherever vaccines are offered. This will help ensure there are not additional barriers to access for this vulnerable population receiving a needed additional dose. CDC is providing further information regarding vaccine administration to immunocompromised individuals to states, pharmacies, health centers, and all vaccine providers.

Does it matter which vaccine I got for the first two doses?

The additional dose should be the same vaccine product as the initial two-dose mRNA COVID-19 vaccine series (Pfizer or Moderna). If the mRNA COVID-19 vaccine product given for the first two doses is not available, the other mRNA COVID-19 vaccine product may be administered. A person should not receive more than three mRNA COVID-19 vaccine doses.

What should immunocompromised people who received the J&J/Janssen vaccine do?

There is not enough data at this time to determine whether immunocompromised people who received Johnson & Johnson's Janssen (J&J/Janssen) COVID-19 Vaccine also have an improved antibody response following an additional dose of the same vaccine. One small study showing immunocompromised people have a more robust immune response to two doses of an mRNA COVID-19 vaccine (Pfizer and Moderna) than to a single dose of Janssen COVID-19 vaccine support use of mRNA COVID-19 vaccines as the primary vaccination series for this population. FDA and CDC are actively working to provide guidance on this issue.

Is there going to be enough vaccine for all these people?


What support is available for providers to reach homebound individuals who need an additional dose?

The Department of Human Services (DHS) received approval from the Centers for Medicare and Medicaid Services (CMS) to modify payments for those administering vaccines to Medical Assistance (MA) beneficiaries who are homebound. This allows providers to receive a higher payment for vaccinating homebound MA beneficiaries and is retroactive to April 1, 2021. This payment will also apply to recipients of boosters. For more information, providers should refer to the Medical Assistance Bulletin, "SARS-CoV-2 Vaccine Administration for Beneficiaries who are Homebound," which can be found here.

If I can't leave my home, how do I get access to an additional dose?

Homebound individuals who are immunocompromised and eligible for an additional dose should consult their health care provider before scheduling a vaccine appointment. Additional information and support for eligible homebound individuals looking for vaccines, including an additional dose, can be found here.

I lost my COVID-19 vaccine card. How do I get a replacement?

We can help by sending you a record of your immunizations! Please visit the PA-SIIS page and complete the Authorization for Release of Immunizations Records Form. 

It is important to note that the PA DOH vaccination record, as well as the CDC vaccination card that individuals receive at the time of their vaccination, are both official proofs of vaccination.