Vaccines are one of the most important advances in public health of the last two centuries. Immunization saves millions of lives every year, and horrific illnesses that were simply unavoidable not all that long ago have now been eliminated.

So why does Sen. Rand Paul (R-Ky.) see them as a threat to liberty?

I testified on Tuesday before a Senate committee hearing on recent outbreaks of measles and other diseases that immunization has mostly wiped out. While most lawmakers on the panel agreed on the importance of vaccination, Paul raised significant doubts. A physician, Paul said that he and his children are vaccinated and that he believes the benefits of vaccines greatly outweigh the risks. But he also registered his opposition to mandatory vaccination, making factually dubious claims in the process.

Paul declared that the government never mandated the smallpox vaccine — conveniently ignoring, among other things, Jacobson v. Massachusetts, the 1905 case in which a man unsuccessfully challenged a vaccine mandate. Jacobson is often considered a seminal decision in public health case law.

Paul said “persuasion” would be a better way to ensure vaccination than would mandates. And he paraphrased Ben Franklin: “I still don’t favor giving up on liberty for a false sense of security” — as if protection afforded by vaccines is merely a matter of perception. He didn’t ask any questions and yielded his time after his statement. Maybe the senator’s only goal was the flood of news coverage his remarks later received.

My perspective on Paul’s comments is shaped both by my research into public health, epidemiology and immunization, and by my experience as a naturalized U.S. citizen who immigrated here after spending most of my childhood living under a dictatorship. I don’t take questions of personal liberty lightly. But Paul is wrong.

Overall, U.S. vaccine mandates strike the right balance between personal freedom and public protection. These mandates work by changing the “balance of convenience” in favor of vaccination by putting bureaucratic hurdles in the way of opting out of them.

There is substantial state-by-state variability in mandates. All states allow exemptions from these mandates for medical reasons, and all but three allow exemptions for “personal belief” or religious reasons. Starting in 2006, I and others have shown that making it more difficult to get an exemption from mandates is not only associated with lower vaccine-refusal rates but also with lower vaccine-preventable disease rates.

But what does “difficult” mean in the context of vaccine exemptions? Essentially, it means requiring administrative steps to get exemptions. For example, some states make parents provide a letter stating why vaccination is against their personal or religious beliefs. In other states, parents seeking nonmedical exemptions are required to go through physician counseling. Another option is requiring parents to watch an online educational video.

All of this is good public policy because vaccine-compliant parents not only protect their own children but also contribute to the protection of other children — including children of vaccine refusers.

Vaccine-accepting parents spend considerable effort to keep their children up-to-date on vaccines: In their children’s first five years, parents have to take kids for about seven vaccination visits. Since few vaccines are 100 percent effective, a proportion of these vaccinated children remain unprotected. This would be okay if everyone else was vaccinated, as well. But refusing parents, in the name of their own freedom, put not only their own children but other children at risk — undermining the compliant parents’ own freedom to choose to protect their children.

So is it really an unreasonable infringement on liberty to expect those who end up increasing everyone’s disease risk to make at least a fraction of the effort that vaccine-compliant parents make? Some requirements, such as physician counseling, have the added benefit of making vaccine decisions truly informed. Even in the three states that do not allow for nonmedical exemptions, the maximum penalty is not allowing unvaccinated children to attend school, often during outbreaks.

I believe Paul when he says he supports vaccination, but I suggest he reconsider his position on mandates. The Franklin quote he nodded to on Tuesday, ironically, means the opposite of what Paul was arguing. When Franklin said, “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety,” he was opposing the Penn family’s attempt to carve out an exception for themselves from the Pennsylvania General Assembly’s attempt to tax their lands for the collective good of frontier defense. The liberty Franklin was defending was the liberty the rest of us deserve now, too — liberty to choose to protect ourselves.

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