Professor Philip Nolan:

It is precisely that. If I pick it up at work and bring it into a typical family household, the chances are that one in two or one in three people in that household will pick it up. If I bring it into an atypical household, let us say a group of college students living together who would not necessarily be as intimate as a family, the chances are somewhat lower, so the attack rate is 10% to 20% in that case. The important message is that we can prevent transmission of the virus. It is not inevitable; it is not magic. It spreads by close, sustained contact, and if we just put that distance between each other and are careful about our hygiene, we can prevent its transmission in households, and we can certainly, by not congregating, prevent its transmission between households. They are the kinds of things we are learning, along with the special circumstances in places, such as meat factories, which seem to particularly promote the transmission of the virus.