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Dr. Saltzman: Some Good News on Response to a Third Dose of SARS-CoV-2 mMRA Vaccines in CLL / SLL Patients and Others with Blood Cancers

In science and medicine, information is constantly changing and may become out-of-date as new data emerge.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.

LLS (Leukemia and Lymphoma Society) has been doing extensive longitudinal research led by Dr. Larry Saltzman on blood cancer patients’ responses to SARS-CoV-2 vaccines.

Due to CLL Society’s collaborative efforts in recruiting for this critical research and, more importantly, due to many of you stepping up to volunteer to be citizen-scientists and give your blood and access to your medical records, their data are enriched with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL / SLL) patients.


  • About half of the patients responded to a third dose after not responding after two doses.
  • Responses still may be lower compared to those who are not immunocompromised.
  • Anti-CD 20 therapies such as rituximab or obinutuzimab (Gazyva) in the past two years markedly suppress response.
  • Many on BTK inhibitors such as ibrutinib do respond to a third dose.
  • Those who had some response after two doses were all amplified by a third dose.


I will have a follow-up interview with Dr. Saltzman, where we update the data after its presentation at the American Society of Hematology Annual Meeting or ASH 2021.

The bottom line is that our response to vaccines is not predictable and often not robust but does improve for some with a third dose. With this and other research, we are beginning to parse out which patients have the better responses.

We still don’t know what level, if any, of an antibody response to a vaccine is protective against COVID-19, so regardless of test results, act as if not vaccinated.

Here are links to three prior trials on vaccine responses in CLL patients:

Here is a link to this LLS trial: Antibody response to SARS-CoV-2 vaccines in patients with hematologic malignancies that discusses responses after the first two doses, but not the third dose discussed in our interview,

For all the details of the trial and the third dose data, please enjoy my interview with Dr. Saltzman.

Thanks to LLS for organizing and funding this vital effort, and thanks to everyone who volunteered in the trial.

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.