By 1900 nearly half the states had school vaccination laws

By 1900, a number of U.S. states had established school vaccination mandates, primarily targeting smallpox, which was the most feared and common vaccine-preventable disease at the time. These laws typically required children to be vaccinated against smallpox in order to attend public schools.

States with School Vaccination Mandates by 1900

(These mandates were mostly for smallpox vaccination)

  1. Massachusetts (1855) – First state to require smallpox vaccination for schoolchildren

  2. New York

  3. Pennsylvania

  4. Illinois

  5. Michigan

  6. Minnesota

  7. California

  8. Connecticut

  9. Ohio

  10. Rhode Island

  11. Wisconsin

  12. New Jersey

  13. Maine

  14. Vermont

  15. New Hampshire

  16. Maryland

  17. Virginia

  18. North Carolina

  19. Missouri

  20. Indiana

  21. Kentucky

These mandates varied in enforcement and scope. For example:

  • Some states required vaccination only during outbreaks

  • Others allowed local school boards to set policies

  • Enforcement was inconsistent and often met with legal and public resistance

Key Historical Context:

  • Jacobson v. Massachusetts (1905): Although after 1900, this landmark Supreme Court decision upheld the authority of states to enforce compulsory vaccination laws and reinforced the legal foundation for school mandates

  • By 1900, at least 11 to 20 states had school vaccination laws on the books, but only a portion enforced them strictly