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CLL Society’s Recommendations for COVID-19 Vaccinated Chronic Lymphocytic Leukemia (CLL) Patients-Based Upon the CDC’s Updated Considerations for People Who Are Immunocompromised and Other Underlying Data

In science and medicine, information is constantly changing and may become out-of-date as new data emerge. All articles and interviews are informational only, should never be considered medical advice, and should never be acted on without review with your health care team.

The Bottom Line:

  1. CLL patients should be vaccinated against COVID-19 as some protection is better than none.
  2. CLL patients should not assume that because they are vaccinated that they are protected.
  3. We recommend that even fully vaccinated CLL patients follow CDC guidelines for the unvaccinated including:
    1. Wearing a well-fitting (preferably N95) mask indoor and in in any crowded situation.
    2. Social distancing.
    3. Handwashing and other protective measures.

The Details:

Our recommendations are based on the CDC’s guidelines: Interim Public Health Recommendations for Fully Vaccinated People that were updated July 16, 2021.

The CDC stated on July 16. 2021:

“People who are immunocompromised should be counseled about the potential for reduced immune responses to COVID-19 vaccines and to follow current prevention measures (including wearing a mask, staying 6 feet apart from others staying they don’t live with, and avoiding crowds and poorly ventilated indoor spaces) to protect themselves against COVID-19 until advised otherwise by their healthcare provider.

Close contacts of immunocompromised people should also be encouraged to be vaccinated against COVID-19 to help protect these people.”


“Data suggest immune response to COVID-19 vaccination might be reduced in some immunocompromised people including, but not limited to, people receiving chemotherapy for cancer, people with hematologic cancers such as chronic lymphocytic leukemia, people receiving stem cells or organ transplants, people receiving hemodialysis, and people using certain medications that might blunt the immune response to vaccination (e.g.,  mycophenolate, rituximab, azathioprine, anti-CD20 monoclonal antibodies, Bruton tyrosine kinase inhibitors).”

These CDC recommendations are in turn based on several studies of vaccine responses in blood cancer patients in general and CLL patients in particular including but not limited to:

What these and other studies tell us that while the numbers differ, we cannot rely on the vaccine to provide us humeral (antibody) protection and we know that without antibodies we are more at risk for severe outcomes with COVID-19 infections.

There are some nuances:

  • Treatment naïve and CLL patients in deep remission long out from their most recent treatments have a good chance of responding well to the vaccine with a rise in antibody levels.
  • Those on a BTK inhibitor such as ibrutinib or acalabrutinib, or on venetoclax or who have received an anti-CD20 monoclonal antibody such as rituximab or obinutuzumab in the last year are very unlikely to have any measurable response to the antibody.
  • T cell response to the vaccine is being studied but T cell function is generally poor in CLL. While it is important to research T cells, it is unlikely results will change the calculations about vaccine efficacy.

Unanswered Questions:

  • Does lack of a robust antibody response post vaccine mean you are not protected?
  • Does a robust response to the vaccine mean that you are protected?
  • How does the Delta and other variants figure in?

CLL Society still recommends based on the few data available that it is safest to assume that if one has no measurable antibodies to the spike protein after the vaccine, it is best to assume one has no dependable protection against COVID-19. Wear a mask!

If one does have a strong antibody response, one likely does have some degree of protection, but it probably less than that of someone without an immune compromising disease. Wear a mask!

The Delta is significantly more contagious and even immune competent, fully vaccinated individuals can get symptomatic COVID infections. CLL patients are even more at risk. Wear a mask!

While we are now recommending following CDC guidelines no matter what the response is to the vaccine, we also recommend discussion with one’s healthcare team about being tested for the spike protein antibody response two weeks or later post vaccine as the information may become important as new data arise.

The Future:

  • Studies will be examining the possibility that an extra vaccine booster might improve protection for some with CLL, though clearly not all patients will benefit. Several countries will be routinely offering CLL and other vulnerable patients a booster. Consider a booster trial if available.
  • Monoclonal antibodies directed against the SARS-CoV-2 spike protein have been or are presently in trials to examine their degree of protection when use pre-exposure for at risk communities such as those with CLL. There is reason to be optimistic based on their efficacy in other settings.

CLL Society has several other articles on related topics if one want to dive deeper including on vaccine response, immunity testing post vaccine, safe and less safe practices, and monoclonal antibodies.

We even have our helpful Explaining to Family and Friends Why the General CDC Guidelines for Those Vaccinated Against COVID-19 Do Not Apply to Chronic Lymphocytic Leukemia Patients

Stay strong.  We are all in this together.

Brian Koffman MDCM (retired) MS Ed
Co-Founder, Executive VP and Chief Medical Officer
CLL Society, Inc.