(CBS SF) — The measles vaccine you received as a child might not be enough to protect you from the disease as an adult, according to the Center for Disease Control and Prevention.

After news broke Wednesday afternoon that Bay Area BART riders may have been exposed to measles from a passenger traveling between the East Bay and San Francisco, some adults may want to consider another vaccination, unless they:

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  • had blood tests that show they’re immune to measles, mumps, and rubella (MMR). Anyone who had measles as a child doesn’t need to worry about getting the disease again.
  • are someone born before 1957. The vaccine didn’t start until 1963, so it’s likely children born before then would’ve lived through a few cycles of the measles.
  • already had two doses of MMR or one dose of MMR plus a second dose of measles vaccine. Two doses of the vaccine are needed for complete protection.
  • already had one dose of MMR and are not at high risk of measles exposure.  Before 1989, children usually received a single dose. After 1989, two doses became the norm.

 
But adults should get the measles vaccine if you are not among the categories listed above, and:

 

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  • are a college student, or other student beyond high school
  • work in a hospital or other medical facility
  • travel internationally
  • are a woman of childbearing age

 
People who are worried they are at risk for measles can have a blood test done to determine their level of antibodies. But the CDC recommends people who are unsure of their immune status to get the vaccine rather than the test. The only measles vaccine currently available is the MMR, the measles-mumps-rubella trio. No vaccine for just the measles itself is available.

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Here’s a timeline of the rise and fall of measles outbreaks and the role the anti-vaccine movement plays: