According to the CDC, Americans born prior to 1957, when measles was rampant, are presumed to have had the illness and therefore to have natural immunity. For adults born later, it’s a matter of tracking down your vaccine records. Whether you received a single vaccine (standard from 1963 to 1989 and 93 percent effective at preventing measles) or two shots (standard from 1989 on and 97 percent effective), you are most likely covered. There’s one caveat, however: A small percentage of people who were vaccinated in the 1960s received a formulation that contained a killed-measles virus, whose protection was found to wane over time, unlike the live-virus vaccine. People in this cohort should get the MMR vaccine. If you had a single vaccine as a child and you’re wondering if you need a second, talk to your doctor. The CDC recommends a second shot for adults at high risk of exposure to measles, such as people who work in health care, college students, and those who travel internationally, but anyone can get a second shot. If you’re unable to track down your records, your doctor can order a blood test to check for immunity, or you can go ahead and get an MMR shot. (There’s no downside, even if it’s an “extra” shot.) There are some people who shouldn’t get vaccinated, such as pregnant women, people who have weakened immune systems, and anyone who has a severe allergy to any of the vaccine’s components.
Source: Questions About Measles
“Vaccines are among the most successful and cost-effective health investments in history. Seth Berkley, CEO of GAVI, the Vaccine Alliance