PHOENIX (3TV/CBS 5) -- The measles outbreak nationwide is getting worse.
The Centers for Disease Control and Prevention is reporting 704 cases in 22 states this year, including Arizona.
It's the highest number of measles cases in the U.S. in 25 years.
Arizona has only had one confirmed case of the measles this year.
But health officials say that can be misleading when you consider the growing number of children in Arizona who have not been vaccinated.
Arizona is considered to be extremely vulnerable to a measles outbreak.
Phoenix grandmother Nancy Gill came down with the measles when she was 4 years old -- before there was a vaccine.
She remembers the pain and suffering and being kept in a dark room.
Gill can't understand why parents don't vaccinate their kids.
"Young people don't know what measles can do," said Gil. "They think its just spots and a rash, and it goes away. They don't know how it can cause blindness, brain damage, deafness, even kill people."
Jessica Rigler of the Arizona Department of Health Services said the latest measles outbreak has raised new questions about whether some older adults -- those born before 1968 -- should be re-vaccinated.
According to Rigler, a booster vaccine necessary in certain circumstances.
If you travel out of the country
Have a compromised immune system
Spend time on a college campus
Work as a healthcare professional
"If you're traveling internationally, there's an ongoing measles outbreak, or working in a health care setting, there's a higher likelihood of coming into contact with someone who has measles," said Rigler. "In some of these situations, we want to make sure your immunity is boosted to offer you the best chance for protection."