@wesleym i liked your reply. I have had nine covid shots. I previously was getting blood draws every 3 months making it easy to track if there was any correlational relationship to changes in my MGUS IFE or FLCs. There was not. But to my surprise, I found a relationship between increasing FLCs and my 4 joint replacement surgeries. I have been noodling another jt replacement surgery so I called and requested a special telephone conversation with my Mayo hematologist. The answer was “no causal relationship” - just maybe normal disease progression. My husband thinks it is the titanium protheses or other parts installed during surgery. Who knows? I have had MGUS now going on 24 years. It probably would not have been discovered if I had not received Internal Medicine care at Mayo where they have a special interest/knowledge with this disease. I have no other “signs” or lab work.