“Your right to punch ends where my nose begins.” That quote, attributed to various sources, is a libertarian maxim — now invoked in connection with COVID vaccine mandates. Here’s the controversy: If the vaccine causes no appreciable injury, can you still refuse to be injected, notwithstanding that you might be visiting significant risks on others?

It’s a close call. Even those who resist government intervention in private matters will endorse rules that bar some persons from violating the rights of others. Ordinarily, those rules ban or limit harm-inducing activities. Occasionally, however, advocates of limited government will condone directives to engage in benign activities (even when not cost-free) if failure to do so might cause injury to innocent bystanders. Safety requirements for nuclear power plants would be one example, or obligatory pollution controls.

Punishing aggressive acts that have already caused damage is a routine government function. But it’s more complicated when government compels conduct that might minimize or alleviate future harm. That’s an area of the law — endangerment — where rights theory is difficult to apply. How much increased risk do I have to endure before your potentially malign failure to act can be redressed? When rights theory doesn’t provide adequate guidance, defenders of liberty often look to utilitarian, cost-benefit tradeoffs. In the context of the vaccine, here are a few relevant factors.

First, how safe is the mandated act? As of this writing, nearly 170 million Americans have been fully vaccinated against COVID. According to the Centers for Disease Control and Prevention, the vaccine — under the most intensive monitoring in U.S. history — is remarkably safe. Adverse events are rare and long-term side effects are extremely unlikely. Moreover, vaccine mandates are nothing new. Wyoming, an indisputably conservative state, requires vaccines for 12 diseases if a child wants to attend either public or private school or a care facility, or participate in school-sanctioned activities.

Second, what’s the magnitude and frequency of an injury that could occur without a mandate? Three groups are at risk: People who, for various reasons, cannot get vaccinated and are therefore exposed to transmission, mainly from others who are not vaccinated. People in states like Texas and Florida who await medical services that aren’t available because hospitals, equipment, and personnel are overwhelmed with COVID cases. And people who must take precautions against, or who have been afflicted by, the new Delta variant. More vaccinations would have slowed transmission and thereby afforded fewer opportunities for the virus to mutate. Significantly, based on data from 40 states, persons fully vaccinated accounted for as little as 0.2 to 6 percent of COVID deaths, and 0.1 to 5 percent of hospitalizations.

Third, can we be sure that a vaccine mandate will remedy the problem? Put differently, haven’t we seen numerous breakthrough cases in which vaccinated persons have nonetheless been infected? Yes, but the key reason breakthrough cases are a growing part of the total is that we’ve vaccinated a higher percentage of the population. Most important, as noted above, people who are fully vaccinated experience far fewer hospitalizations and deaths.

Fourth, are there remedies available that are less intrusive than a vaccine mandate? Perhaps periodic testing is the answer. But many if not most people would find that alternative to be more burdensome than a quick, zero-priced jab in the arm. Perhaps we should just wear masks and maintain social distancing. But the consensus is that the vaccine would still be necessary, and far more effective. Perhaps natural immunity from contracting the disease is stronger than vaccine-induced immunity. But most studies say otherwise.

Perhaps a vaccine mandate can be geographically or demographically constrained. That’s an obvious consideration, which suggests that local officials be given substantial discretion in establishing the scope of any mandate. Or perhaps vaccinations could remain optional, but with restricted access to selected activities by the unvaccinated. That notion — a vaccine “passport” — has the support of nearly 82 percent of Americans, according to a recent survey.

Finally, what peripheral concerns need to be addressed before implementing compulsory injections? What will be the enforcement process, and the punishment for non-compliance? Will there be reporting requirements? Data tracking? Will special interests — drug companies being one example — exploit their government-conferred market power? Will politicians use the next crisis to rationalize even more invasive decrees?

Those are crucial questions, which should be examined before embarking on a program that encroaches on personal autonomy. And yet, we are in the midst of a health emergency, which means that suitably modified, narrowly-tailored, time-limited rules may be justified.