Unlike peanut butter, Vegemite isn't commonly allergenic. It's not good for those who are on a low-salt diet, but salt intolerance isn't an allergy per se. My better half suffers from Hashimoto's, among other things she can't handle any but the minimum amount of gluten - but she can eat Vegemite.
The fact that it’s not commonly allergenic strengthens the probability that Australians might be stripped of their citizenship and get deported if found to be allergic to it. I wonder if the silence on the issue is all part of a coverup.