It was feared by the Elizabethans because for those who contracted the plague, only the lucky, had a fifty percent chance of surviving.
To prevent a wide-scale outbreak of the plague, Henry the VII, shut down theatres to prevent large gatherings of people to prevent an environment were the illness could thrive (Shapiro). The Black Plague was responsible for killing one-quarter of the population of London in the outbreaks of 1653 and 1603 (Mabillard).
Since the plague was the most feared illness of Shakespeare’s time it is no surprise it appeared in his writing. Shakespeare made references to the plague in several of his plays, King Lear, Romeo and Juliet, Othello, and Henry VI (Mabillard). In the tragedies, we have read the clearest connection to the black plague was in King Lear. Lear uses the plague as a way to describe his daughter Goneril in an insulting manner by calling her a plague sore:
“But yet thou art my flesh, my blood, my daughter;
Or rather a disease that 's in my flesh,
Which I must needs call mine: thou art a boil,
A plague-sore, an embossed