Until they mutate. It is beneficial to the survival of a virus to infect the largest group that it can. A virus targeted to a small group of people has a larg

Until they mutate. It is beneficial to the survival of a virus to infect the largest group that it can. A virus targeted to a small group of people has a large "survival benefit" the moment it can mutate to infect everybody. In addition, it's really hard to target a biological entity at a specific subgroup of humans. From a biological standpoint, all humans are damn near identical.