This country is as racist as hell against white people, and everybody knows it.
However... if I were black (or even Hispanic), I'd have to wonder --- could this possibly, just possibly, be an attempt to "cull the herd"? To address, ahem, birth rates that outstrip those of the contraceptive-crazy white populace? To practice "genocide light"? I do know that black people had reservations about the swine flu vaccine during the Ford administration (I think it was), for that very reason. Given what they've had to contend with in this country, their apprehension was entirely understandable.
And, you know, there is such a thing as being able to direct different kinds of vaccines to different populations. If a restaurant chain can color in the "O" in the company's name, when taking the applications of black job seekers, there are certainly far more malignant ways to encode things without detection.
Just thinking out loud.