To do this job, you need to have a Ph.D. or MD. Most colleges are also very selective about who gets in. Getting into medical school means taking and passing the MCAT.
Once your degree is achieved, you must also spend a couple of years getting certified by an accredited immunology program. You know what that means…yep—another exam to pass.
Then it's time to get to work. It is important to publish your work and stay current on the latest advancement in your field. Would you go to a dentist who has never heard of Novocain?