[alphonsegaston]

It's not at all meaningless but reflective of the fact that notions of race (or something like it) are entirely subjective and variable across cultures, even across time within cultures. Whites, as an American example, did not in our recent past include all kinds of people from countries in the Mediterranean or Eastern Europe. The same is true of ethnic categorizations.

And yes, some ethnicities being susceptible to diseases is a social construct because ethnicities follow the same shifting standards. Your talking about the intersection of an imprecise categorization with biological understanding that is only dependent on the latter to remain true. It's useful today because (in some societies) it can signal aspects of biology. But human societies in the future could have entirely different notions of race and ethnicity that change or renders the overlap meaningless.