boom –v. to grow or expand suddenly
vaccine –n. a substance that is usually injected into a person or animal to protect against a particular disease
dose – n. the amount of a medicine, drug or vitamin that is taken at one time
tourist –n. a person who travels to a place for pleasure
attract –v. to cause (someone) to like or be interested in something
change hands –v. to move in ownership from one person to another
