Doctors have found through common sense and experience that the immune system’s ability to fight off microorganisms is improved by resting and drinking fluids. No one had to do studies. It is a self-evident fact, and no one is about to suggest that doctors stop making that recommendation until a Harvard Medical School research program can be completed in which 1,000 people with the flu will be allowed to drink fluids and rest and 1,000 others with the flu will be made to walk around while deprived of fluids.
Chiropractic is based upon the same logic. If there is an interference in the nerve system, the immune system, which is intricately linked to it, will not function as well as it should. Just as it would be ridiculous to demand that physicians do the study outlined above to prove the validity of rest and fluids for the flu, it would be just as ridiculous to demand research to prove that chiropractic helps the immune system work better. It is a self-evident fact. If the nerve system works better, every system in the body works better, including the immune system.
Notice that chiropractors do not claim that chiropractic cures the flu, the common cold or anything else. Chiropractors just maintain that if there is an interference in the nerve system, the immune system will not work as well as it should, and if that interference is removed, the immune system will work better.