These ain't idiots, either. Dawn is Pakistan's largest English-speaking newspaper, with offices throughout the world.
This story has been on-going for three days, with WND breaking it over here, and no one denying it.
Either it's true, in which case it takes awhile for it to sink in and for responsible parties to figure out what happens next; or it's disinformation.
But I seriously doubt there's a mother or father in Pakistan who doesn't know the difference between smallpox, cow pox and chicken pox.