SACRAMENTO (CBS13) — More than 100 measles cases have been confirmed across 21 states, and 18 people tested positive for the virus in California.

“It’s contagious and you’re not immune to everything,” said a mother of two, Korina Gonzales.

READ MORE: Monday's Show Info. (7/4/22)

She tries to take every precaution to protect her children, and that means they’re fully vaccinated from the measles and especially important for her oldest going back to school.

RELATED: Measles Case Reported In Fresno County, Others May Have Been Exposed

“He’s got a weaker immune system, so it’s tough when other parents don’t vaccinate their kids because it could definitely affect my kids,” Gonzales said.

State Sen. Richard Pan says those who aren’t vaccinated have a 90 percent chance of catching measles if exposed.

“If you’ve received two doses of the vaccine you’re 98 percent protected most likely for your life,” he said. “If you’ve been in a room where someone had the virus, even two hours later, you can catch measles.”

Most children get their first vaccine at the age of 1 and the second at 4-years-old.

So, where is the virus coming from?

READ MORE: Fire Damages Commercial Structure In Arden-Arcade

RELATED: Europe Blames Anti-Vaccination Movement For Surge In Measles Cases

“People didn’t get their children vaccinated and they go travel overseas, right now there’s a large measles outbreak in Europe, in fact, several people have died in Europe and they catch measles and come back,” he said.

A measles outbreak at Disneyland in the winter of 2014-15 prompted legislation removing some vaccine exemptions for students. The measure was authored by Pan. Parents who lost their exemptions rallied to protest the push to require vaccines.

RELATED: People Not Vaccinated For Measles Urged To Avoid Disneyland

“We’re willing to risk a childhood illness than risk something more serious like autism,” said a person opposing the state mandate.

Pan disagrees and says as long as parents vaccinate their children, the community is less at risk.

“There have been numerous studies to show that vaccines do not cause autism, they do not cause neurological problems, autoimmune problems, vaccines are safe,” he said.

Infants are highly susceptible to catching the virus because they’re too young to get their shots.

MORE NEWS: Father Drowns In Lake Berryessa While Trying To Save Son

Symptoms generally appear a week or two after the infection and can begin with a high fever and a cough, then followed by a rash.