Imagine a science fiction novel written 20 years ago, where every person infected with a deadly virus infects two other people, and the carriers are asymptomatic, and up to 5% of the known cases die. Imagine a story where people can't interact with each other. People can't visit their parents. Movie theaters and other public events are canceled. The economy shuts down. And people get so agitated that there are riots in the streets.
It certainly would have seemed like science fiction.
Actually, the 2011 movie Contagion had every detail spot on except for the deadliness of the disease.