While other nations have criminalized the spread of vaccine misinformation — and have higher vaccination rates — the response by states and the U.S. government has largely been limited to combating misconceptions with accurate information, said Michelle M. Mello, a professor of law and health policy at Stanford University.

She noted that even laws that cited a “compelling interest,” like public health and safety, to police disinformation ran the risk of having a chilling effect, a First Amendment standard for many courts.

“Initiatives like this will be challenged in court and will be hard to sustain,” she said in an interview. “That doesn’t mean it’s not a good idea.”