On this topic of the booster...not the make up of the booster but getting it period. I saw my Immunologist last week. I had been on steroids (10 mg/day for 4 weeks) prescribed by my Rheumatologist. My questions related to "Do I need the booster given I am on steroids and given several other immune liabilities?" (Other liabilities: monoclonal gammopathy of unspecified origin; prior pancreatic cancer 5 years ago treated with surgery (and spleen removal) and chemo, etc. and the fact of a low IgM for years...very low for unknown reasons and a not too good functioning IgG). Given all this what would his recommendation be? 1. He said I am at the "highest" risk for Covid (I am double vaxed) and should get the booster ASAP. After we talked, I asked what about testing to see if I have antibodies from the shot...he approved of the idea despite CDC saying we don't know what levels mean in the test results. We agree that would be our guide as to when (not if) I get #3. Well, unexpectedly to both of us I am in GREAT shape...high antibodies (not from infection) and so I can wait until the immunity wanes around October. I will likely as for the antibodies to be checked again as I happen to have gotten PMR 2 weeks after the 2nd Moderna shot and hunch it tripped of the reaction. I am 77. What is reassuring is that I did mount an immune response (tho was not on steroids at the time of the shots) despite all the various things NOT in my favor. I prefer NOT to add another shot to this picture unless my antibodies go way way...and they may....then I will risk the 3 rd anyway. Hope this might be useful to some on this list. Sharon