Although there is overwhelming evidence to show that vaccination is a highly effective method of controlling infectious diseases, a vocal element of the chiropractic profession maintains a strongly antivaccination bias. Reasons for this are examined. The basis seems to lie in early chiropractic philosophy, which, eschewing both the germ theory of infectious disease and vaccination, considered disease the result of spinal nerve dysfunction caused by misplaced (subluxated) vertebrae. Although rejected by medical science, this concept is still accepted by a minority of chiropractors. Although more progressive, evidence-based chiropractors have embraced the concept of vaccination, the rejection of it by conservative chiropractors continues to have a negative influence on both public acceptance of vaccination and acceptance of the chiropractic profession by orthodox medicine.