• People with myeloproliferative neoplasms (MPNs) may be eligible to receive a third dose of the Pfizer or Moderna COVID-19 vaccine at least 28 days after their initial two doses.
• The Centers for Disease Control and Prevention (CDC) also has recommended Pfizer COVID-19 vaccine booster shots for adults over 65 and other high-risk individuals at least six months after their second Pfizer dose.
• There is currently no official guidance for additional shots or boosters for those who have received the Johnson & Johnson vaccine.

People with myeloproliferative neoplasms may be eligible to receive a third dose of either the Pfizer or Moderna COVID-19 vaccine shot. Additionally, those who have received two doses of the Pfizer vaccine may be eligible for a Pfizer booster shot.

On Aug. 12, the U.S. Food and Drug Administration (FDA) amended the Pfizer and Moderna vaccines’ emergency-use authorizations to allow certain immunocompromised individuals to receive a third vaccine dose at least 28 days after their second dose. Some immunocompromised people do not develop an adequate immune response after the two-dose vaccination series.

Individuals defined as immunocompromised include:

• People receiving active cancer treatment for tumors or cancers of the blood
• People who received a stem cell transplant in the past two years
• People who are organ-donor recipients and taking immunosuppressive drugs
• People taking high-dose steroids or other immunosuppressive drugs, as well as those with certain other health conditions

People with MPNs may qualify as immunocompromised under the above criteria. The CDC recommends individuals consult their doctors to determine if a third dose is appropriate for them.

There is not yet guidance from the FDA or CDC on additional doses for immunocompromised people who received the Johnson & Johnson vaccine.

Do People With MPNs Need Additional Vaccine Doses?

Although many people with MPNs have well-functioning immune systems, some might become immunocompromised as a result of treatments. In particular, people who have undergone a hematopoietic cell transplant (HCT) or chimeric antigen receptor (CAR) T-cell therapy often experience a weakened immune system for an extended period of time, as these therapies directly affect a person’s white blood cell counts.

HCT or CAR T-cell therapy may increase the likelihood of coronavirus infection and may also cause the vaccine to be less effective. Therefore, it is generally recommended that people in treatment for MPNs get vaccinated promptly, potentially with an additional dose, to reduce the risk of COVID-19.

The CDC and FDA recommendations for third doses of the Pfizer and Moderna vaccines “are for those patients whose immune systems are compromised — and that would include every single person who has a blood cancer,” said Dr. Matt Kalaycio, a board-certified hematologist and a professor at the Cleveland Clinic Lerner College of Medicine at Case Western Reserve University, in an interview with myMPNteam in September.

“Everyone with blood cancer is not really fully vaccinated unless they get that third dose,” Dr. Kalaycio added.

Dr. Kalaycio assured people with MPNs and other blood cancers that the Pfizer and Moderna COVID-19 vaccines work. “They do create an immune response, but not to the degree that it does in the normal population. So the third dose does seem to bring the immunity up to the level of everybody else,” he said.

Individuals with MPNs should speak directly with their providers about any safety concerns or best practices about timing their COVID-19 vaccine with their treatments.

Vaccine Booster Shots

Some people with MPNs may not qualify for a third dose of the vaccine 28 days after their second Pfizer shot. However, they may be eligible to receive a Pfizer booster shot under new guidelines from the Centers for Disease Control and Prevention. These boosters — also authorized by the FDA — are intended for those who received the two-dose series of the Pfizer vaccine but then experienced a drop in immunity over time.

On Sept. 24, the CDC recommended booster shots of the Pfizer COVID-19 vaccine at least six months after a second dose in the following groups:

• People 65 and older
• Residents of long-term care facilities
• People ages 50 to 64 with underlying medical conditions that place them at high risk for severe COVID-19

The CDC recommendations state that people ages 18 to 49 with underlying medical conditions and people ages 18 to 64 who are at risk of COVID-19 exposure due to their work or living arrangements may receive a booster shot of the Pfizer vaccine based on their individual benefits and risks.

The CDC and FDA have not released booster recommendations about the Moderna vaccine or the single-dose Johnson & Johnson vaccine. Both companies have submitted data on booster shots to the FDA for review.

Learn More About COVID-19 Vaccines

“We recommend vaccinations for all of our patients with blood cancers, and the only exception to that rule are those who have had stem cell transplants in the last three months,” Dr. Kalaycio stated in his September conversation with myMPNteam.

Dr. Kalaycio previously answered questions about the COVID-19 vaccines in March. In that conversation, he spoke in greater detail about COVID-19 vaccination and treatments and answered questions about vaccine safety.

Talk To Your Doctor

If you have an MPN, talk to your doctor about whether you qualify now to receive a third COVID-19 vaccine dose or a booster.