Dear Debra,
Laws governing health record retention vary from state to state. For instance, in Texas, the cummulative health card or record must be kept by the public school for at least two years after the student's withdrawal (http://www.tsl.state.tx.us/slrm/recordspubs/sd.html#part5).
There are similar state laws governing health record retention requirements by hospitals and providers, but you cannot expect these institutions to keep your medical information beyond that period.
If you wish to preserve your medical records, you need to do that for yourself. Using HealthFrame is a great way to get started now and to make sure that you preserve your medical information going forward. If you haven't already, please download a demonstration copy from http://www.recordsforliving.com/HealthFrame/Demo/Request.aspx
Your best chance of reconstructing your immunization record is to start with your primary care physician, if you have one. Try and get as much information from him/her as you can, including adult immunizations such as flu shots or tetanus boosters. You may need to keep inquiring your other doctors going as far back as you remember your providers. Parents may be a useful resource too. They might remember your pediatrician contact information or they might have partial immunization records.
Records For Living is doing its best to encourage individuals to take control of their health management. Additionally, we're part of nationwide efforts to make medical information available to patients, so that they can have access to their records whenever they need.
Good luck,
Support Team