The US Leukemia and Lymphoma Society (LLS) has been running a study specifically focused on US patients with Leukemia or Lymphomas, looking at how well the vaccines in use in the US are at creating antibodies in that population. We’ve previously reported on their overall summary: “Get Vaccinated, Act Un-vaccinated“. (And in particular, see the last part of this summary for some excellent FAQs from vaccinated blood cancer patients.)
The LLS has recently posted a video given by Dr. Larry Saltzman, the Executive Research Director of the LLS, providing more details behind their results. There are many statistics of interest to WMers, although some of them also need to be taken with an understanding of their possible weaknesses, at this point of our medical knowledge. More research is clearly needed, and the study continues — we hope to hear more results from them in a timely manner.
You can see the video, or read the transcript with the slides that Dr. Saltzman used. In your humble reporter’s mind, the best material starts just before the 14-minute mark of the video, and concludes at about the 29 minute mark where the FAQs begin, or from about page 9 of the transcript to page 14 of the transcript, inclusive. (Some of the FAQs are specific to the study, which, in Canada, we cannot participate in; some of the FAQs are redundant with what has already been presented; and some of the FAQs are specific to the US healthcare system. Your mileage may vary. Scanning the transcript may be your best bet, to save yourself some time.)
Here is a short summary, and some of the reasons to be cautious about leaping to conclusions from the numbers that are given.
- Given that this is a US study, the only Covid vaccines included were the Pfizer and Moderna.
- Also, given that this is a US study, the number of days between first and second doses of vaccine was quite small, with an average of 26 days. There is now some evidence that an increased number of days between vaccine doses is actually more effective. But the science is not complete on this, yet.
- The definition that determines whether a person “responded to the Covid vaccine” is somewhat questionable, at least at this point of the science. As the CDC says (slide 18 of the presentation referenced below), “Exact correlation between antibody level and protection from COVID-19 remains unclear”.
- For the entire population of WM patients (treated or not) in the study, only 74% showed a response to Covid vaccines.
- It is entirely possible that a large portion of that 26% non-response may be due to treatments
- Since the study is a self-volunteer study, rather than a randomly-selected set of patients, there may have been a selection bias among the WM patients in the study, in that those who volunteered may have been those more likely to have been treated one (or more) times
- Averaged across all of the different cancer types, having been treated within the past 2 years was definitely significant. Unfortunately, the impact of specific treatments was not broken down by cancer type. There is likely some commonality across cancers, but there may also be some unknown differences. For example, a WM patient treated with Rituximab (Rituxan) may be more (or less) likely to still mount a vaccine response than a CLL patient treated with the same drug. That being said, the following data is available in the paper:
(no vaccine response)
|Rituximab (Rituxan) (but no indication if this is solo, or in combination with other drugs)||56%||44%|
|“Chemotherapy” (but could be any number of chemo combinations, considering the breadth of diseases covered in the study)||26%||74%|
Obviously, this is the kind of science that we need to see more of. Science is hard. We can’t expect immediate gratification on questions such as this.
We eagerly await further data and conclusions from them!
(For anyone who would like to dive further into the reasoning around additional doses for immunocompromised people, you may want to look at this presentation from the CDC on the topic. And for those who want specific guidance on getting their own antibody test done, slide 18 of this presentation directly addresses the question. And lastly, for a pithy summary of the subject from the IWMF Connect that we reported on earlier, check out this post.)