For months, and stretching back into 2015 and 2016, the United States and other regions of the world have been experiencing a return of sporadic outbreaks of mumps and measles. With such diseases mostly eradicated, they became socially inconsequential. As new outbreaks erupt each week, that is no longer the case.

Early this month health officials reported two measles cases in Dallas County, Texas, bringing to 15 the total logged in the state this year. Measles outbreaks affecting 285 in Brooklyn, N.Y., prompted government officials to mandate vaccinations or face a $1,000 fine. All told, there are more than 600 measles cases in the United States — an amount that threatens to overtake the 667 cases logged in 2014, the record for cases since the disease was thought to be eradicated in 2000.

Add to this that cases of the mumps are spiking as well. Indiana University this month announced that 20 students have contracted mumps — bringing the total to more than 400 nationwide.

Our longstanding safeguard of herd immunity — the ability of the community, including those who have been vaccinated, to avoid infection — is now threatened. We are seeing the return of diseases that had previously disappeared from the developed world because of the anti-modern prioritization of squeamishness regarding needles delivering vaccinations for children’s health.

As a free society, we justifiably have a moral intuition that we allow others to make choices for themselves as long as they do not harm others. This is why we are primarily concerned with herd immunity, as opposed to the harm families may choose to inflict on themselves.

But how big is the harm that families inflict on themselves? A few years ago, as part of an academic paper, I constructed estimates of the cost of failing to get vaccinated, stated in terms of the value people would typically be willing to pay to avoid bearing a similar risk.

That is to say, we can put it in dollar terms how much internal harm people cause themselves by failing to get vaccinated, ignoring the costs to other members of society by putting herd immunity in danger.

Economists and various governmental agencies, as a matter of standard practice, already try to figure out how much people are willing to spend to reduce risks of mortality. The number the EPA uses is $9.4 million in 2019 dollars (their website expresses it in 2006 dollars).

Elsewhere, the FAA calculated another set of values to translate severity of injuries in terms of the $9.4 million value of saving a life. Depending on the disease, the most frequent outcome may correspond to their injury classifications of “Minor,” “Moderate,” “Serious” or “Severe.”

Using EPA value, “Minor” injuries cost $18,800, “Moderate” injuries cost $145,700, “Serious” injuries cost $540,500, and “Severe” injuries cost $1,762,500. These numbers are meant to represent how much people would hypothetically be willing to pay to avoid the injury.

Mumps, perhaps, belongs in the lowest category, in which case its cost is $18,800. This would be to assume that getting the mumps is no more discomforting or painful than getting a pinky sprain. The total cost of the 20 cases at Indiana University would then be $376,000. These numbers obviously will increase rather quickly if the disease is worse and its harm is more than a pinky sprain.

After consulting various studies in medical journals, I had previously calculated the increase in likelihood of infection by three diseases — whooping cough, chicken pox and invasive pneumococcal disease — should you not get vaccinated.

We can combine these numbers together to estimate the internal cost of failing to vaccinate.

If we apply “Severe” injury number for all three diseases, the implicit cost you are bearing by not getting the whooping cough vaccine is $497. For invasive pneumococcal disease it is $696. For chicken pox, it is $56. Note that I am ignoring all other vaccines, and I am ignoring the risk of death. I am also assuming that parents do not value their own children’s health more than their own, a point many parents would object to.

One estimate found that 1.3 percent of children in a recent cohort do not get vaccinated. Since there are about 74 million children in America, we can estimate that there are 962,000 who are not vaccinated.

The costs of failing to receive these three vaccines, actuarially applied to these 962,000 children, total $1.2 billion.

Another way of thinking about these numbers is that, in other contexts, this is money that people would be normally be willing to spend to eliminate the risks posed by the diseases. In the age of overprotecting children and strollers that cost as much as a used car, the failure to vaccinate is, at the least, incongruous.

Antiscientific populism, then, presents a real problem even if failing to vaccinate were to have no effect on herd immunity. Still, our values dictate that peoples’ choices are to be respected. As an economist though, I do wonder why we do not consider applying other, similar economic estimates of the costs people pose to society by failing to vaccinate, and taxing them this amount if they make this choice.