A Big Win for School Vaccine Requirements: The Second Circuit Reaffirms Miller v. McDonald

This is big news for vaccine law.

Today, the U.S. Court of Appeals for the Second Circuit issued its long-awaited decision on remand in Miller v. McDonald, once again upholding New York’s repeal of its religious exemption to school vaccination requirements. While many legal eagles expected this outcome, it is nevertheless an important victory for states seeking to maintain strong school immunization laws.

To understand why this decision matters, it’s worth taking a step back.

In December 2025, the U.S. Supreme Court did something that caught the attention of virtually everyone who follows vaccine litigation. Rather than simply denying review, the Court granted certiorari, vacated the Second Circuit’s earlier decision, and sent the case back, a procedural move known as a grant-vacate-remand (GVR). The Court instructed the Second Circuit to reconsider the case in light of its recent decision in Mahmoud v. Taylor.

That made many of us nervous.

Mahmoud involved parents objecting to public school instructional materials that conflicted with their religious beliefs. The Supreme Court recognized a significant parental religious liberty claim in that context, prompting questions about whether the Court was signaling a broader willingness to rethink long-settled vaccine jurisprudence. As I wrote previously, vaccine mandates have historically occupied a unique place in constitutional law. For more than a century, courts have repeatedly pointed to compulsory vaccination as the classic example of a public health measure that may burden religious exercise without violating the Constitution.

The question after the Supreme Court’s remand was whether Mahmoud changed that.

Today, the Second Circuit answered with a clear and unanimous no.

The court reaffirmed that New York’s school vaccination law is a neutral and generally applicable law under the Supreme Court’s Free Exercise doctrine. It rejected arguments that repealing the religious exemption reflected hostility toward religion or that retaining a medical exemption somehow made the law constitutionally suspect.

That distinction is important. Medical exemptions exist because some children cannot safely receive certain vaccines. Religious exemptions, by contrast, increase the number of unvaccinated students without advancing the public health objectives of the vaccination program. As the Second Circuit explained, those two exemptions serve fundamentally different purposes, and treating them differently does not violate the Constitution.

Accordingly, the court held that the traditional constitutional framework still applies. Because the law is neutral and generally applicable, it is reviewed under rational basis review, not the much more demanding strict scrutiny standard.

The court then turned to the question everyone was waiting for: Does Mahmoudexpand Wisconsin v. Yoder in a way that requires strict scrutiny for school vaccine mandates?

Again, the answer was no.

The Second Circuit explained that Mahmoud concerned something fundamentally different from vaccination. That case involved government-directed educational instruction that parents believed interfered with the religious formation of their children. New York’s immunization law, by contrast, does not dictate religious beliefs, require students to affirm any ideology, or expose children to state-sponsored messages that conflict with their faith.

Instead, it simply establishes a health-and-safety condition for attending school.

That difference proved decisive.

The court concluded that while vaccination requirements may burden some families’ religious exercise, they do not burden parental religious formation in the same way that concerned the Supreme Court in Mahmoud and Yoder. Because the burden is different in kind, not merely degree, Mahmoud does not require strict scrutiny.

Perhaps most significantly, the opinion repeatedly grounds its reasoning in more than a century of Supreme Court precedent. The court reaffirmed decisions including Jacobson v. Massachusetts, Zucht v. King, and Employment Division v. Smith, while also relying heavily on its own prior vaccine decisions, including We the Patriots. The panel emphasized that even Mahmoud reaffirmed the longstanding principle that neutral, generally applicable laws may impose incidental burdens on religious exercise.

In other words, Mahmoud did not rewrite vaccine law.

That conclusion closely mirrors what many legal scholars anticipated following the Supreme Court’s remand. Professor Zalman Rothschild’s Harvard Law Review Forum essay suggested that the GVR signaled at least some interest among the Justices in reconsidering vaccine mandate jurisprudence. But many also expected that lower courts would distinguish cases involving educational curriculum from those involving communicable disease control. That is precisely what the Second Circuit has now done.

What happens next?

The plaintiffs will almost certainly ask the Supreme Court to review the case once again. Whether the Court accepts it remains to be seen. But for now, this decision provides one of the strongest post-Mahmoud appellate opinions reaffirming the constitutionality of school vaccination requirements.

For those of us who were watching this case closely, today’s decision is more than just another appellate opinion. It offers important reassurance that longstanding vaccine precedent remains intact. The Second Circuit has made clear that Mahmoud is about parental control over religious formation in the educational setting, not about dismantling more than a century of public health law.

The Supreme Court may ultimately decide it wants to revisit these questions itself. But unless and until it does, Jacobson and the long line of cases supporting school vaccination requirements remain firmly in place.

That’s welcome news for public health.