Hi Deryl, welcome to Mayo Clinic Connect. You'll notice that I moved your question to the Blood Cancers & Disorders group. I did this because you'll find members talking about MGUS in this group and can connect with people like @gingerw @auntieoakley @anniemaggie @susangs @momofthree1 @gmajudy @cctoo @dazlin

Here are a couple of other discussions that may interest you.
- Always run down with MGUS: https://connect.mayoclinic.org/discussion/always-run-down-with-mgus/
- MGUS https://connect.mayoclinic.org/discussion/mgus-2d464e/

I see that you are looking for a cause for your recent MGUS diagnosis and ask about the vaccine or a-fib meds being the potential culprit. The precise cause of MGUS isn't known. Genetic changes and environmental triggers appear to play a role. It may be a frustrating pursuit to seek the cause. By connecting with others here, I hope that you can turn your focus and energies to coping with the diagnosis and staying healthy.

What questions do you have? Has your doctor set up a follow-up schedule? How frequent?

Hello Deryl,
Given that MGUS is usually present for many years before it is discovered, it is unlikely the vaccine contributed in any way to a recently diagnosed case. I found the following article helpful.

"Incidence of Monoclonal Gammopathy of Undetermined Significance and Estimation of Duration Before First Clinical Recognition", Terry M. Themeau, et al. https://pubmed.ncbi.nlm.nih.gov/22883742/

There are MGUS patients that report an increase in their M spike post vaccine. I think your scenario for MGUS post vaccine could be possible - but also impossible to determine without doing MGUS screening pre and post vaccine - so no way to confirm the theory.

Can only say that my PCP informed that after 2 Moderna Innoculations + 2 M boosters, I do not have covid immunity.
Possibly this is due to IgM kappa MGUS dx 7 years ago. Now suggested to take extremely new med: Evusheld. Anyone have any experience with it? Thank you! @rae

Me…I’m wondering if that’s what did it.