I'm not sure where you have seen it "peter out". Hong Kong is down to single digits in new cases and may have it under control. But that, through heroic efforts, not a "petering out".
The only outbreak we have seen in a multi-ethnic society is the one in Toronto, and I've seen no ethnic breakdown on the victims. Have you?
I think Ivan T. indicated the victims in Toronto were largely Asian. Among places where the disease seems to have petered out, I was thinking of, besides Canada, the U.S. and India.