• The Centers for Disease Control and Prevention (CDC) has approved a second COVID-19 booster shot of the Moderna or Pfizer messenger RNA (mRNA) vaccines for people over 50 years old and those who are immunocompromised.
• The Leukemia & Lymphoma Society recently began recommending a second COVID-19 booster shot for people with blood cancer and most survivors.
• People with myeloproliferative neoplasms (MPNs) should talk with their oncology teams about whether they should time any booster shots around cancer treatments.

The CDC and U.S. Food and Drug Administration (FDA) have authorized and recommended a second booster shot for individuals older than 50 and those with immunocompromising conditions.

The American Cancer Society states that it “supports the National Comprehensive Cancer Network (NCCN) recommendation that all people with cancer should be fully vaccinated against COVID-19. Since the situation for every person is different, it is best to discuss the risks and benefits of getting the COVID-19 vaccine with your cancer doctor, who can advise you.”

People living with myeloproliferative neoplasms are typically considered immunocompromised, which can lead to an increased risk for severe disease and hospitalization from COVID-19. The new public health recommendations come after recent studies showed an immune response to the Moderna and Pfizer vaccines in many immunocompromised people, including individuals with blood cancer.

The New Recommendations

Some important details about these recommendations include the following:

• This booster is for people who received their first booster at least four months ago.
• This fourth shot would be of either the Moderna or Pfizer vaccines, not the Johnson & Johnson vaccine.
• Even if you were previously vaccinated with the Johnson & Johnson vaccine, it is now recommended that this next dose be a Moderna or Pfizer vaccine only.
• For those who are immunocompromised and who have received a three-dose primary vaccination followed by an initial booster, this additional booster counts as a fifth shot.

How Booster Shots Can Protect People With MPNs

If you already had your first booster shot, you may be wondering what the research says about whether boosters are effective for people with blood cancers. Findings from the Leukemia & Lymphoma Society showed that, although about 25 percent of people with blood cancer did not generate antibodies after their initial two COVID-19 vaccine doses, 43 percent had an immune response after receiving a third shot, emphasizing the importance of boosters.

The American Society of Hematology advises people with MPNs to get vaccinated “as soon as possible.” In addition, the Leukemia & Lymphoma Society recently began recommending a second COVID-19 booster shot for people with blood cancer and most survivors. The organization advises waiting at least four months after your previous booster dose of the COVID-19 vaccine. Speak with your oncologist if you’re unsure of your risk or the timing of your vaccines around treatments.

“I got my booster vaccination today — so far, so good,” one myMPNteam member wrote. Another said, “Got my Pfizer booster yesterday. Sore arm but otherwise OK!”

Response to the Moderna Vaccine

The CDC’s latest recommendations follow promising new results about the effectiveness of the vaccines in immunocompromised people. A recent study from Moffitt Cancer Center included people diagnosed with blood cancers, as well as individuals with solid tumors. Researchers tested levels of antibodies, the proteins the immune system makes to help destroy a target. In this case, the antibodies were to SARS-CoV-2, the virus that causes COVID-19, made in response to the Moderna COVID-19 vaccine.

On average, antibodies against the coronavirus were identified after the second vaccine dose in about 90 percent of the study’s 515 participants. About 85 percent of people with blood cancers showed an antibody response.

People who had the following treatments generally had lower responses to the vaccine:

• Anti-CD20 monoclonal antibodies (including rituximab, sold as Rituxan) less than six months before vaccination
• Bruton tyrosine kinase inhibitors (such as ibrutinib, sold as Imbruvica)
• P13K inhibitors (such as idelalisib, sold as Zydelig) used to treat a variety of cancers
• Venetoclax (sold as Venclexta)
• CD19 chimeric antigen receptor T-cell (CAR-T) therapy

People who had the following treatments showed a stronger response to the vaccine:

• Autologous (self) stem cell transplants in the past year
• B-cell maturation antigen CAR-T therapies
• Allogeneic (donor) stem cell transplants

Response to the Pfizer Vaccine

Although this recent study included only people given the Moderna vaccine for COVID-19, other research has looked at the response of immunocompromised individuals to the Pfizer vaccine. These vaccines are based on the same technique, using mRNA to teach cells how to make a protein that will trigger an immune system response and help prevent a SARS-CoV-2 infection.

In one study that included individuals with medical conditions that caused them to be immunocompromised (including blood cancers), immune system response was, on average, about 67 percent.

Why These Results Matter

Additional doses of mRNA vaccines may be effective at increasing detectable antibodies in a similar way to the first and second doses. Other research indicates that antibody levels are likely to decrease over time, so getting booster doses at recommended intervals is necessary even for vaccinated people who made antibodies after their initial shots.

Simply making antibodies does not guarantee complete immunity from COVID-19 infection, but the findings from these studies are a good sign that the mRNA vaccines for COVID-19 can trigger strong responses — even from people with compromised immune systems. It’s evidence that vaccines can protect people at higher risk of severe infections.

According to the CDC, getting vaccinated is still the best way to protect yourself and slow the spread of the virus. In addition, the Leukemia & Lymphoma Society advises people with blood cancer to get vaccinated even if they’ve had COVID-19.

Find Your Team

On myMPNteam, the online social support network for those with myeloproliferative neoplasms, you can connect with other people who understand life with MPNs. Here, members come together to ask questions, give advice, and share their stories with others who understand.

Are you planning to get another COVID-19 vaccine booster? Do you have concerns about vaccine effectiveness, vaccine response, or time of vaccination? Share your insights in the comments below, or start a conversation by posting on myMPNteam.