The disease is starting to spread to other states, though, and the first measles death in over a decade was reported last month, prompting people to question their own immunization status. Is it time for a booster? Or will that dose you received as a toddler protect you? And what should you do if you weren’t vaccinated as a child?

The majority of the people getting sick right now have not been vaccinated, so if you received the vaccine earlier in life, you likely have some degree of protection. Exactly how much protection, however, often comes down to your age. Here’s what you need to know.

When do people typically get the measles vaccine?

The vaccine for measles, which also protects against mumps and rubella, is typically given to children at two stages of their life. The first shot, as recommended by U.S. health agencies starting in 1989, is at age 1, with the other typically given between the ages of 4 and 6.

Should I get a measles vaccine booster?

No vaccine is perfect, but this one, often called MMR, has been shown to be 97% effective for people who have two doses.

That said, if you were vaccinated before 1968, you likely received an early version of the vaccine that was made from an inactivated virus. That vaccine was not nearly as effective and the Centers for Disease Control and Prevention recommends that anyone vaccinated between 1957 and 1968 get at least one dose of the live vaccine. (Measles was so widespread prior to the 1960s that people born before 1957 are assumed to have natural immunity.)

“People vaccinated prior to 1968 with either inactivated (killed) measles vaccine or measles vaccine of unknown type should be revaccinated,” the CDC says. “They should get at least 1 dose of live attenuated measles vaccine.”

High-risk individuals are also being encouraged to get an additional dose of the vaccine, including people who work in health care and college settings as well as those traveling internationally or to an area where there’s an active outbreak.

I only received one dose of the measles vaccine as a child. Should I get the second now?

One dose of the live vaccine is 93% effective against measles, the CDC says. For most people, that is a sufficient degree of protection.

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I was never vaccinated for measles. Should I do so now?

Generally, that’s a good idea. The CDC, however, suggests you first check with your healthcare provider if you’ve had a previous allergic reaction to a MMR vaccine or have severe allergies, are or may be pregnant, have a weakened immune system , have a history of seizures or have recently gotten any other vaccine.

I’m still nervous about the measles outbreak. Is there a risk in getting a measles booster shot?

The measles vaccine has been used for decades and health officials say it’s very safe. There’s no harm in getting a shot if you’re unsure of your vaccination status, though be warned you could face the usual side effects, which include soreness, temporary pain and a fever.  

Robert Kennedy said Vitamin A “can dramatically reduce measles mortality.” Should I take that instead of getting vaccinated?

No. Despite the U.S. Health and Human Services Secretary touting Vitamin A and cod liver oil, he has acknowledged that vaccines are the way to prevent a measles infection. The treatments he discussed were meant for people who have already become infected.