Jacobson... settled that it is within the police power of a state to provide for compulsory vaccination

The mere assertion that the case is one involving the construction or application of the Constitution, and in which the construction of federal laws is drawn in question, does not, however, authorize this Court to entertain the appeal; and it is our duty to decline jurisdiction if the record does not present such a constitutional or statutory question substantial in character and …

—the Supreme Court upheld a city ordinance requiring that children be vaccinated before attending any school, public or private.

Indeed, the Supreme Court has consistently recognized that a state may constitutionally require school children to be immunized.

The state may enact reasonable regulations to protect the public health and public safety of school children, and compulsory immunization is a permissible exercise of the state's police power.

—noting that "in the exercise of the police power reasonable classification may be freely applied, and [a] regulation is not violative of the equal protection clause merely because it is not all-embracing

—it considered an equal protection and due process challenge to ordinances in San Antonio, Texas, that prohibited a child from attending school without a certificate of vaccination.

This is based on settled Supreme Court precedent that "a state may... delegate to a municipality authority to determine under what conditions health regulations shall become operative and that the municipality may vest in its officials broad discretion in matters affecting the application and enforcement of health law."

States thus have the power, within constitutional limits, to pass laws that "provide for the public health, safety, and morals [.]"