The US government has a duty to protect its citizens from the spread of disease. When a child is not vaccinated, this increases the risk of harm for both the individual child and the rest of society. The lack of federal action on this matter makes everyone vulnerable.
A medical exception should be incorporated into a National Vaccine Mandate to allow medical professionals to weigh this risk against individual medical risks such as vaccine-related allergies. However, philosophical objections from parents do not represent a legitimate justification for the endangerment of children and society at large. Thus (and in accordance with the Supreme Court's rulings), any National Vaccine Mandate should not permit a philosophical objection.