SAN DIEGO (CBS 8) – Doctor Mark Shalauta says he's not surprised a measles outbreak originating in mid-December at Disneyland has now spread to different parts of Southern California. The problem, he says, is parents who choose not to vaccinate their kids.

"It's really sad because in 2000, measles was considered eradicated from the U.S., and now we're seeing this huge rise," he said.

Shalauta is a family physician at the Scripps Clinic in Rancho Bernardo. Over the past few weeks he's had several people call in with questions about the measles vaccine. We had some of our own.

First: If you don't remember getting the vaccine and don't have the records to double-check, what are your options?

"Options are getting a blood test or doing the immunization," Shalauta said.

A blood test can show if you're immune, and if you choose not to go that route, getting the vaccine again is perfectly safe.

Next question: If you've already had measles, should you get the vaccine if you haven't done so already?

"If you had that completely confirmed that you had measles as a child, then you are immune to measles," Shalauta said.

Still, he warns, the vaccine also protects against mumps and rubella. So it is a good idea to get it.

What if you are vaccinated, but received the shot decades ago? Do you need to get it again?

"If you were born before 1957 then you are considered immune, because chances are you had the measles so you are immune," Shalauta said.

After 1957, he says you should have received two shots to increase immunity – one around 12 months of age and another at age 5. If you did not get that second shot, chances are you should.

Finally: If you're vaccinated and spending time with others who aren't, should you be concerned? The answer is yes, but only a little. Shalauta explains while the vaccine is extremely effective, it's not 100 percent, which is why precautions should always be taken.

"For example, if someone comes into the clinic here and I were to go see them, if they're suspected, I would be wearing a mask," he said.

Keep in mind that the measles is highly contagious and sometimes deadly. It starts with flu-like conditions, followed by a rash that starts at the hairline and works its way down the body.