COVID-19 Booster Shots for Most Cancer Patients: What to Know

Medically Reviewed By: Amy Sherman, MD

If you have been vaccinated against COVID-19, the U.S. Centers for Disease Control and Prevention (CDC) recommends different numbers of vaccines depending on if you are immunocompromised.

Immunocompromised people can include 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 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 with high-dose corticosteroids or other drugs that may suppress your immune response

An additional dose is considered a required part of the vaccination series that helps certain immunocompromised people achieve full vaccination. In other words, a primary series for immunocompromised people is three doses of the mRNA vaccine (Pfizer or Moderna).

booster dose is another dose given to fully vaccinated persons to extend their immune response. It is not the same as an additional dose.

Who needs a third dose of a COVID-19 vaccine?

For moderately or severely immunocompromised people (including most cancer patients), the CDC recommends three doses of the FDA-approved Pfizer-BioNTech or Moderna vaccines as part of the primary vaccination series. That third/additional dose should be at least 28 days after your second dose, and you should try to get the same vaccine that you received for your first two doses.

Individuals who are immunocompromised who received the FDA-approved Johnson & Johnson/Jansen should receive a total of three doses as part of their primary vaccination series. It is recommended that the second and third doses be a mRNA vaccine, meaning the Moderna or Pfizer-BioNTech shots. The second dose should be given at least 28 days after the first dose. The third dose should be given at least 2 months after the second dose.

A COVID-19 vaccine.
A COVID-19 vaccine.

Who needs a first booster (fourth dose)?

The CDC recommends a first vaccine booster (fourth dose) for immunocompromised people who have completed their three-dose primary vaccination series.

The first booster shot (fourth dose) is recommended at least three months after the the third dose of the primary series. The mRNA vaccine (Pfizer-BioNTech or Moderna) is preferred.   

Who needs a second booster (fifth dose)?

The CDC recommends a second vaccine booster (fifth dose) for immunocompromised people who have completed their primary vaccination series and their first booster vaccine. 

The second booster (fifth dose) should be given at least four months after their first booster. The mRNA vaccine (Pfizer-BioNTech or Moderna) is preferred.  

If I am not moderately to severely immunocompromised, which vaccines should I receive and when?

For non-immunocompromised individuals, the primary vaccination series is either two doses of the Moderna or Pfizer-BioNTech  vaccines, or one dose of the Johnson & Johnson/Jansen vaccine.

A single booster dose is recommended for all adults who have completed a primary vaccination series at least 5 months prior.  An mRNA COVID-19 vaccine (Pfizer-BioNTech or Moderna) is preferred. 

A second booster dose is recommended for adults 50 years and older who have completed the primary series and a first booster dose. The second booster should be given at least 4 months after the first booster.

Remember to talk with your doctor if you have any questions about what is right for you.

Which kind of additional shot or booster should I get?

For primary and booster vaccinations, the CDC recommends an mRNA COVID-19 vaccine, like those provided by Moderna or Pfizer BioNTech, over the Johnson & Johnson vaccine.

However, if you are eligible for a vaccine booster, the CDC advises that you can get whichever type of vaccine you prefer. Some people may want the vaccine type that they originally received, while others may prefer to get a different booster. For example, you might choose to get a certain booster because it is easily available to you, or because of potential side effects or reactions.

Where should I get another dose?

If you are eligible for an additional dose or booster shot, you should get one soon at a location that is convenient to you. Community locations, such as CVS and Walgreens pharmacies, offer additional vaccine doses to eligible patients right now. You do not need a doctor’s note to get a booster or additional dose at these locations. Find one near you at or

Why should you get another dose?  

Research shows that people being treated for cancers such as leukemialymphoma, or multiple myeloma are more likely to get very sick if they get COVID-19. They may also have a longer illness. Data suggests that additional doses of the Pfizer-BioNTech or Moderna COVID-19 vaccines, for example, may provide more protection against these risks.

recent study found that individuals actively being treated for cancer had lower immune responses to the COVID-19 vaccines compared with non-immunocompromised individuals, though it was still sufficient to protect against severe disease. Patients who received mRNA vaccines like those offered by Pfizer-BioNTech and Moderna had stronger responses than those who received the Johnson & Johnson vaccine. An additional dose also induced a higher immune response, and it was safe and well tolerated.

It has been found that a booster dose significantly increases vaccine effectiveness against COVID-19 hospitalization and infection, including against the Omicron and Delta variants.

The CDC continues to recommend that everyone age 5 and older protect themselves from COVID-19 by getting fully vaccinated, including receiving a booster shot.

For the very latest on COVID-19 vaccines from Dana-Farber, visit this webpage.