Immediately call your healthcare provider and let them know that you have been exposed to someone who has measles. Your healthcare provider can determine if you are immune to measles based on your vaccination record, age, or laboratory evidence and make special arrangements to evaluate you, if needed, without putting other patients and medical office staff at risk.
If you are not immune to measles, MMR vaccine or a medicine called immune globulin may help reduce your risk of developing measles. Your healthcare provider can advise you, and monitor you for signs and symptoms of measles.
If you are not immune and do not get MMR or immune globulin, you should stay away from settings where there are susceptible people (such as schools, hospitals, or childcare) until your healthcare provider says it’s okay to return. This will help ensure that you do not spread it to others.
Source: CDC: Questions about Measles