The U.S. is dealing with a measles outbreak, with nearly 500 cases confirmed already this year and people over 30 might be at risk of contracting the disease even if they’ve been vaccinated. Between 1957 and 1989, the CDC recommended only one shot of the MMR vaccine, before changing it to two shots in 1989. As a result, people between the ages of 30 and 62 might not be fully protected. The CDC says most cases of measles involve people who were unvaccinated. But if you fall into that age category, check your medical records and consult with a doctor to see if you need better protection.