I have a friend that has travels a lot for her job. She trains doctors, nurses and their staff on how to use our company's product. Since she has started this job she has been getting sick a lot. She has been going to a nurse practioner who says her immune system is low and once it gets back up she will be fine. Well she got sick again over the weekend. She is fine today but is wondering what she can do to get her immune system back up. Any suggestions? She is going to find a different doctor because the nurse keeps giving her antibotics but it doesn't seem to help get her immune system back up.