As the legislature moves ever closer to adjournment (still scheduled for Friday the 15th), one of the unanswered questions is, Will the House take up a Senate-passed bill that would eliminate the philosophical exemption to childhood vaccinations?

If you ask me, I suspect the House will leave it hanging till next year. Lawmakers could plausibly argue that the issue hasn’t gotten a full airing this time around, since the Senate passed the provision as an amendment to a barely-related bill.

Although, on the other hand, no amount of discussion and airing will satisfy the anti-vaxxer crowd, so why not just lance that boil?

We’ll see. But while the issue is still pending, I thought I’d present a short-form version of the argument for vaccination.

Vaccines work.

Well, maybe a slightly longer-form version.

Opponents of mandatory vaccination say there’s always uncertainty in medical practice, and cite past examples of practices that turned out to be harmful. The overzealous use of radiation, for one. The problem is that vaccination has been a near-universal practice for decades. It’s almost certainly the most common medical procedure of all, and I doubt that it’s even close.

This is not some new, random experiment; it’s an established procedure with a very, very, very long track record. Any procedure will produce some complications; but in the case of vaccines, the number of complications is vanishingly small compared to the number of doses given.

What are we getting in return for exposure to a very small risk? Well, the folks at Vox.com produced a chart showing the reduction in illnesses and deaths from vaccine-preventable diseases, before and after a vaccine became available. The results are striking: Many diseases saw a 99-100% drop in deaths, and a 96-100% drop in number of cases.

The whole thing is too big to reproduce, but here’s a sample.

Can you look at that chart and deny that vaccines have been one of the great medical advances of the past century? Not unless your mind is already made up.

In 2013, the Institutes of Medicine — a widely respected organization that has often been critical of mainstream medical practice — undertook a thorough review of all relevant research on vaccine safety, and found “no evidence of major safety concerns associated with adherence to the childhood immunization schedule.”

That’s a level of certainty even more impressive than the scientific consensus on climate change.

In 1900, one in ten American children died by the age of six. Vaccines are a big part of the dramatic increase in childhood survival. That’s why veteran Vermont pediatrician Dr. Nancy Davis testified that “Vaccines are one of the great public health triumphs of the 20th Century.”

Vaccines are so successful, in fact, that the menace of childhood disease is only a faint and distant memory. But, as one expert told a Senate committee, “None of these diseases is dead.” All are capable of making a comeback if vaccination rates fall too far.

Which brings us to herd immunity. In order for vaccines to work, the lion’s share of the vulnerable population must be vaccinated. The percentage varies from disease to disease; the highest, measles and whooping cough, require a more than 90% vaccination rate. Most other diseases are in the low to mid-80s.

Vermont has one of the higher non-immunization rates in the country, somewhere around six percent. It rose slightly in the past year, but still appears to be above the herd immunity threshold. But there are two problems.

— Some schools and school districts have much lower immunization rates, below the level needed to maintain herd immunity.

— As one expert told a Senate committee, not every vaccination takes effect. In fact, about 10% of vaccinations fail. This means our effective vaccination rate is actually lower than the official statistics, and may be below the herd immunity threshold.

The majority of exemptions granted in Vermont are philosophical — just under four percent. As long as that rate doesn’t go much higher, we should be okay (except for the pockets of low immunization). But those lobbying to keep the philosophical exemption are also fighting to spread doubt about the safety of vaccines. If they have their way, more and more people will seek philosophical exemptions. That will open the door to outbreaks of preventable diseases, and then we’ll be trying to lock the barn door after the horse is gone.

All of Vermont’s mainstream medical establishments support ending the philosophical exemption, including the UVM Medical Center, UVM Children’s Hospital, Dartmouth-Hitchcock, the Vermont Medical Society, and the Vermont branches of the American Academy of Pediatrics and American Academy of Family Practice. Maybe it’s because I have medical professionals in my family, but I can’t swallow the conspiratorial notion that all these people are on the take.

Anti-vaxxers want to frame the issue as a matter of personal and parental rights. But there’s another way to look at this: the social contract.

In a large society, we must balance freedom with mutual responsibility. As Oliver Wendell Holmes said, “The right to swing my fist ends where the other man’s nose begins.” The evidence on vaccines is so overwhelming, that their widespread use must be considered a social good — a matter of responsibility to one’s fellow humans.

I don’t necessarily favor the repeal of the philosophical exemption — as long as very few people take advantage of it. But every person who does so is metaphorically swinging their fists, and the more people do so, the more noses will be broken.