The measles, mumps and rubella vaccine is very safe, and two doses is 97% effective — which means 97% of people will develop lifelong immunity against the disease.

Once again:

• If you were born before 1957: you are presumed immune because measles was so widespread.
• If you were vaccinated before 1967: you should get a booster shot as the original vaccine wasn’t as strong as the later vaccine.
• If you were vaccinated between 1967 and 1989: you should consider a booster shot. They originally thought you got lifelong protection from one shot, but later realized you needded two shots.
• If you were vaccinated after 1989: you are presumed immune.