Mandatory vaccination requires an act of the legislature in the state: here is the law for Washington state. The Dept. of Health is empowered to set certain rules within the confines of the law passed by the legislature. The law requires "full immunization" against "certain vaccine-preventable diseases in accordance with schedules and with immunizing agents approved by the state board of health", which are given here for the current year. These requiremnts are set up following RCW 28A.210.140, which does not specify any particular medical standard. The meningococcus vaccination requirement is part of the law, but the chicken pox vaccination requirement is not cooked into the law, it is a rule of the Dept. of Health. The courts generally defer to the DoH in setting those rules that implement the law authorizing the m to
adopt reasonable rules regarding the presence of persons on or about
any school premises who have, or who have been exposed to, contagious
diseases deemed by the state board of health as dangerous to the
public health. Such rules shall specify reasonable and precautionary
procedures as to such presence and/or readmission of such persons and
may include the requirement for a certificate from a licensed
physician that there is no danger of contagion.
Applied to covid vaccines, the question is whether it is reasonable to require vaccination against the disease, and using which vaccines? I expect that this may get tested in court, but at present there are no mandatory vaccination rules for covid in Washington. It is not definitionally unreasonable to require vaccination using a medicine that has not received full approval by the FDA (though perhaps some state may include a limit on possible vaccines – but I doubt there are any such statutory limits). It might be deemed unreasonable to require vaccination with a vaccine known to be unreliable and dangerous.
Washington law allows exemptions and includes "philosophical or personal objection" but then specifically disallows such exemption in the case of MMR. No state mandates vaccination when the vaccination is medically counter-indicated. In Washington, the "personal objection" exemption is available, unless the legislature passes a new law exempting covid vaccination from the exemption.
Mississippi does not allow personal or even religious objection exemptions. There is a medically-based exemption which boils down to "is not necessary". Like Washington, there is no (current) requirement for a covid vaccination analogous to the varicella vaccination requirement, so the question of legally mandating use of authorized but not approved vaccines does not arise. Here is a synopsis of proposed legislation in the US. NY State has a bill prohibiting mandatory covid vaccination for school attendance.
Public universities, on the other hand, can and do widely mandate vaccination for in-person class attendance. This is generally possible because state laws allow state universities to set the rules for their operation (not requiring the legislature to make every decision). In the case of the University of Washington, this resulted in Executive Order 60 in 1986, in response to the rise of HIV. That in turn created a committee on communicable diseases, which can and did make recommendations for mandatory vaccinations, which were accepted and implemented by the administration – for students. The verification procedure is not yet figured out.
