YSK: You are personally responsible for keeping copies of your immunization records.

Most people assume their childhood doctors or school has a copy of their medical records, but those institutions are only legally obligated to keep those records for a specific amount of time depending on the state. You may need a copy of those records if you ever work in education, healthcare, join the military, police, or certain branches of government or decide to travel. You should call your high school and/or doctor and ask for a copy of those records and if they have them ask for 2 sets of OFFICIAL COPIES, meaning that the copies will either be embossed or signed by the person distributing them. They do not have to be official copies, but it doesn't hurt if they are. If they do not have those records, fear not. You can get an antibody titer test which will test your blood for antibodies and a proof of vaccine can be created using those tests. These things can take time and so it is something you should have on hand just in case.