Vaccination Exemptions

In 1855, Massachusetts became the first U.S. state to require vaccination for schoolchildren. At that time, only smallpox vaccine was available. Other states and localities began to pass similar regulations, though the rules were often only spottily enforced.

England had been more aggressive in mandating vaccination: the Compulsory Vaccination Act of 1853 required infants born in England and Wales to be vaccinated for smallpox, though it allowed an exemption for “those unfit for vaccination.” An 1871 expansion of the law tightened enforcement of the requirement. However, objections to compulsory vaccination led to an active, organized anti-vaccination movement.

The British Vaccination Act of 1898 provided a conscience clause to allow exemptions to mandatory smallpox vaccination. This clause gave rise to the term “conscientious objector,” which later came to refer to those opposed to military service. By the end of 1898, magistrates had issued more than 200,000 vaccination exemptions.

Today in the United States, all states require that children be vaccinated for certain diseases before school entry (the required immunizations vary by state). A variety of exemptions are allowed, depending on state and local regulations. Mississippi and West Virginia offer only medical exemptions to vaccination. In other states, medical, religious, and often philosophical/personal belief exemptions are available. The California legislature passed a law in 2015 that eliminates non-medical exemptions; this will go into effect in mid-2016.

Medical Exemptions

All 50 states allow children to be exempted from vaccination requirements for medical reasons. These reasons generally include the following situations:

  • The child’s immune status is compromised by a permanent or temporary condition. For example, the child might have a congenital condition leading to an impaired immune system. Or, the child might take medications, such as chemotherapy or steroids, that impair the immune system. In either case, vaccination could be harmful to the child’s health.
  • The child has a serious allergic reaction to a vaccine component.
  • The child has had a prior serious adverse event related to vaccination.

Religious Exemptions

Forty-eight states allow exemptions to vaccination for religious reasons (though this number will drop to 47 once California's legislation goes into effect in mid-2016). Some states statutes indicate that to receive a religious exemption, a family must belong to a religious group with bona fide objections to vaccination. They may, as Iowa does, ask a parent to attest that "immunization conflicts with a genuine and sincere religious belief and that the belief is in fact religious, and not based merely on philosophical, scientific, moral, personal, or medical opposition to immunizations." Other states simply require that a parent sign a form stating that he or she has religious objections to vaccination.

Several legal cases involving the constitutionality of religious exemptions to vaccination have been tried. The rulings have in general upheld the right of states to mandate vaccination in spite of parents’ religious beliefs. At the same time, courts have often found that requiring parents belong to certain religious groups to qualify for religious exemptions violates the Constitution’s Equal Protection clause. The argument is that the Equal Protection clause should protect all people who claim a religious objection to vaccination, not only those who belong to a certain religion with recognized objections.

Personal Belief Exemptions

Twenty states allow exemptions to children whose parents have philosophical or personal belief objections to vaccination (Vermont and California will be removed from this list when legislation that eliminates the exemption goes into place in mid-2016). In most cases, parents must file a one-time or annual form with a school district attesting to a personal objection to vaccination. In states with all three types of exemptions, personal belief exemptions tend to be most common. And, in states that allow philosophical and personal exemptions from vaccination requirements, such exemptions increased from 0.99 to 2.45% between 1991 and 2004.

A Washington state law that took effect in July 2011 requires that parents seeking vaccination exemptions for their children discuss the benefits and risks of vaccination with a health care provider. The state allows medical, religious, and personal belief exemptions, and has an overall exemption rate of 5.2% in the 2014-15 school year. California and Oregon in recent years have enacted similar requirements.

Implications for Disease Outbreaks

Overall, vaccination rates in the United States remain high. But many experts are wondering what the effect will be on public health of increasing numbers of children being exempted from vaccination. Some point to the increasing measles incidence that emerged in England after a study (published in 1998 but since withdrawn) proposed an association between MMR vaccination and autism. Vaccination rates in England dropped in response, from more than 90% to 80% or lower. Measles cases, meanwhile, began to rise. While only 56 cases were confirmed in Wales and England in 1998, 1,843 were confirmed by 2013.

One U.S. study showed that children with nonmedical vaccination exemptions were 35 times more likely to contract measles than vaccinated children. Another study showed a similar risk with pertussis (whooping cough). And several measles epidemics have been traced to religious communities that do not commonly practice vaccination. In Philadelphia in 1990-91, nine children died from measles centered in a religious community that shunned vaccination.


  1. Public Health England. Confirmed cases of Measles, Rubella, and Mumps in England and Wales: 1996 to 2016. Updated 27 March 2017. Accessed 01/17/2018.
  2. Feikin, D.R., Lezotte, D.C., Hamman, R.F., Salmon, D.A., Chen, R.T., Hoffman, R.E. Individual and community risks of measles and pertussis associated with personal exemptions to immunization. JAMA. 2000;284:3145-3150.
  3. Hodge Jr., J.G., Gostin, L.O. School vaccination requirements: historical, social, and legal perspectivesKY Law J. 2001-2002 Summer;90(4):831-90. SSRN. Accessed 01/17/2018.
  4. Iowa Department of Health. Immunization Branch. Certificate of immunization exemptions Q&A. Accessed 01/17/2018.
  5. Novak, A. The religious and philosophical exemptions to state-compelled vaccination: Constitutional and other challenges. (1.8 MB). Accessed 01/17/2018.
  6. Omer, S.B., Pan, W.K., Halsey, N.A., et al. Nonmedical exemptions to school immunization requirements: secular trends and association of state policies with pertussis incidence. JAMA. 2006;296:1757-63.
  7. Salmon, D.A., Haber, M., Gangarosa, E.J., Phillips, L., Smith, N., Chen, R.T. Health consequences of religious and philosophical exemptions from immunization laws: individual and societal risks of measles. JAMA. 1999;282:47-53.
  8. Washington State Department of Health. Washington State school immunization data, 2014-2015 School Year. 2015. Updated April 2015. (407 KB). Accessed 01/17/2018.

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Last update 17 January 2018

Assessment Questions

Which exemption is the only type allowed for children in all 50 states?

  • Religious exemption
  • Personal belief exemption
  • Philosophical belief exemption
  • Medical exemption

True or false? Overall, vaccination rates in the United States remain high.

  • True
  • False

Studies have shown that children with nonmedical vaccination exemptions are __________ to contract certain vaccine-preventable diseases than children without those exemptions.

  • much less likely
  • somewhat less likely
  • more likely
  • just as likely
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