Anti-vaccinationism in chiropractic is widespread, as is the case for most forms of alternative medicine, but there are notable differences within the trade. Chiropractic is an alternative medicine founded on the idea that all disease is caused by disruption of the flow of "innate" (or innate intelligence) in the spine, by so-called vertebral subluxations – a pseudoscientific concept. Over time chiropractic has divided into "straights" who adhere to the subluxation theory and "mixers" who adhere more closely to a reality-based view of anatomy. "Straight" chiropractors are very likely to be anti-vaccination, but all chiropractic training tends to reduce acceptance of vaccines.
Chiropractic anti-vaccinationism has led to negative impacts on both public health and mainstream acceptance of chiropractic.
Most chiropractic writings on vaccination focus on its alleged negative aspects, claiming that vaccination is hazardous, ineffective, and unnecessary. Chiropractic training increases opposition to vaccination, and prominent anti-vaccinationists such as Andrew Wakefield have spoken at chiropractic conferences.
Some chiropractors have embraced vaccination, but a significant portion of the profession rejects it, as original chiropractic philosophy traces diseases to causes in the spine and states that vaccines interfere with healing. The extent to which anti-vaccination views perpetuate the current chiropractic profession is uncertain. The American Chiropractic Association and the International Chiropractors Association support individual exemptions to compulsory vaccination laws, and a 1995 survey of U.S. chiropractors found that about a third believed there was no scientific proof that immunization prevents disease. The Canadian Chiropractic Association supports vaccination; a survey in Alberta in 2002 found that 25% of chiropractors advised patients for, and 27% against, vaccinating themselves or their children. Chiropractors have lobbied against pro-vaccination measures such as the removal of personal belief exemptions to vaccine mandates.
In the United States, courts have examined chiropractic objections to vaccination. The United States District Court for the Southern District of Ohio ruled in the 1985 case of Hanzel v. Arter that belief in chiropractic ethics did not constitute a religious belief justifying exemption from vaccination under a statute permitting religious exemptions. In the 2015 case of Head v. Adams Farm Living, Inc., the North Carolina Court of Appeals ruled that a chiropractor was not competent to attest to the need for a medical exemption for vaccination.