This is not correct. In an extreme case, if there is only 1 left unvaccinated, the disease won't spread. If there are two left unvaccinated, the chances of one having the disease and the other being initially uninfected and then subsequently infected by the one possible vector is astonishingly small.

In reality, for a vaccine to be effective, the portion of the population that needs to receive that vaccination is significantly less than 100%.

Moreover, vaccines based on attenuated vaccines (e.g., the polio vaccine) actually infect the recipient with an impotent version of the virus. This virus will be transmitted to others in the community through normal contact, thus conferring immunity to many that did not receive the vaccination directly.

(this isn't intended to be an endorsement of those who refuse to get vaccinated)

Irrelevant. In reality, for a vaccine to be effective, public policy must target 100% vaccination.

(this isn't intended to be an endorsement of those who refuse to get vaccinated)

You may not be endorsing it, but it's important to point out that this argument is ethically dubious.

My favorite ethical test is Kant's categorical imperative, which is briefly that an act is ethical if everyone else can act the same way. For example, if you're wondering whether it's ok to slip onto the subway just as the doors are closing, delaying the train by just a second, you can ask: what if everyone boarded the train that way? Of course, the train would never depart, being constantly delayed by each as-the-doors-close boarder.

If everyone thought that vaccines are ok for others but not themselves, then no one would be vaccinated. Thus this argument is unethical. Let's go beyond "not endorsing" it-- let us all actively condemn it.

There are a bunch of other actions that most people would consider perfectly ethical that fail this test too. Is going childless ethical? If everyone did that, we'd all die out. How about going to your favorite hamburger joint? If everyone did that, the line would be miles long, and nobody would get served.

The problems work in the other way too: there're some actions that people do consider unethical where there are no problems if everyone did it. Consider cheating (by a constant percentage) on your tax returns. If everyone did it, the government would just raise tax rates to compensate, everyone would end up paying the same taxes anyway, and nobody would be worse off (except perhaps having to throw an additional calculation in). Yet few people would say that cheating on your taxes is ethical.

Why is going childless considered okay, yet killing your infant considered abhorrent? They have the same effect on the world - in both case, there's no kid. They have the same effect on the world if everyone does them - in both cases, we all die out. And yet one is considered fine while the other is highly unethical.

The categorical imperative is a nice heuristic to determine whether some behavior will benefit the greater good, but it's also nothing more than that. There is nothing inherently 'ethically dubious' about deviating from a rule of thumb, firstly because the heuristic returns false positives and secondly because you may disagree whether something is a 'greater good'.

If you want to argue that this deviation from this rule of thumb is 'ethically dubious', you'll have to argue exactly that and not argue some blanket claim that everyone should disagree with.

The categorical imperative is not the only or best rule, but it is a good rule of thumb. It's a good test in this case because it clearly demonstrates the folly of going unvaccinated-- if everyone relies on "herd immunity" there will be no herd immunity.

It matters what we say. The mixed messages out there already are dangerous. Kottke put it best in TFA:

So get your kids (and yourselves) vaccinated and save them & their playmates from this whooping cough bullshit, which is actually killing actual kids and not, you know, magically infecting them with autism.

As long as only a small percentage rely on "herd immunity", we're fine. If only those who actually have severe reactions to vaccines rely on "herd immunity", we're fine. Even if a few nutjobs fear autism and a few others simply don't get around to it, we're fine.

The problem is that too many people are relying on it for foolish reasons (fear of autism) and not weighing the risks appropriately. Going unvaccinated without extremely good reason, in the present circumstance, is foolish, but don't overgeneralize.

As an entire country, you are correct (for many diseases, especially ones who have vaccines in the 85% effectiveness ranges). The range of the outbreaks will largely be limited to those 15% who didn't get immunity once vaccinated, and the remainder of those who aren't vaccinated due to their ignorance.

However for small groups, they GREATLY increase the chance of the disease hitting your population. By small groups, I mean circles of friends, co-workers, schoolmates, nurserymates, etc. You should IMMEDIATELY kick people from those groups, as they increase your and your children's chances of getting infected quite a bit. (Remember, you and your children have a 15-30% of the vaccine you DID take to not work).

Remember, you're not looking at just 15-30% from one disease. They have 0% immunity to EVERY disease.

Something people overlook is that the slippery slope fallacy is only a fallacy in a logical context. People aren't uniformly logical entities, and slippery-slope arguments are not always fallacious when applied to human actions.

At some point in any analysis of human behavior and ethics, philosophy is no longer the right tool for the job. You have to turn to psychology.

The US Constitution doesn't provide any mechanism for a public policy of vaccination (the existence of NIH, CDC, etc notwithstanding). While such a policy might be desirable, overstepping the extent of federal power granted by the Constitution would, in your Kant explanation, lead to a collapse of all Constitutional control [1]. That would be bad, so we can't allow the single transgression.

I'm in favor of getting vaccinated. I even ensure that I'm up-to-date on everything whenever I leave the country. However, our society is founded on individualist ideals. We are not communitarians or collectivists, and the fact that my action might not be optimal for the community as a whole does not constitute a rationale for controlling my behavior. This is why we tolerate free speech even from evil people; it's why we're willing to let some criminals go free in order to prevent punishing the innocent, etc.

[1] Not that this hasn't happened already.

If you want to do otherwise you will always have the freedom to do so. But according to the latest science, there is no publicly acceptable argument for going unvaccinated or for advocating against vaccinations.

I have a friend whose son is mentally handicapped, apparently [1] because, as an infant, his vaccination was both (a) done incorrectly and (b) massively overdosed.

I say this not to advocate against vaccination, but to remind that no medical procedure is without risk. Accidents happen, and there are also individual circumstances that would make some treatments unadvisable.

A statement as categorical and sweeping as yours is taking things too far.

[1] Nobody will ever be able to prove it, but the evidence is convincing to me.

UPDATE: forgot to mention about the (very small) inherent danger in using attenuated virus vaccines, such as the OPV (Sabin, not Salk) polio virus. It seems that in this case, it mutates and reverts to the virulent, paralyzing form in 1 / 750,000 cases [2]. This is tiny, but you can't categorically call it safe.

[2] http://en.wikipedia.org/wiki/Polio_vaccine#Iatrogenic_.28vac...

Any time you stick a needle into someone, you risk giving them a brain embolism. Life is risk. However vaccines are CLEARLY in the make you much safer part of risk, like seatbelts and washing your hands.

Even if your near-baseless statement of risk is accurate, it is clear that a non-vaccinated world is much riskier for children than a vaccinated one.

In one case, yes, but the danger of malpractice is certainly well known.

In my other case (iatrogenic polio), it's a very well documented effect. Virtually all polio in the USA since the 'late 60s (give or take) has been the result of this.

But in both cases, the risk is vanishingly small.

My point was that a statement like "stop whining: it's perfectly safe" is not correct. In the end, such hyperbole only gives the tinfoil hat crowd a toehold.

And again, using the polio example, an understanding of the tiny risk of iatrogenic polio can help those at particular risk due to immune problems to avoid what is a non-trivial danger for them.

And you're right, the risk of an ill effect is non-zero. That doesn't mean it's not safe, though. If our definition of safe means absolutely zero risk, then almost nothing is safe. Relative to most medical procedures, vaccines are incredibly safe.

I'm going to continue telling everyone I know that they should vaccinate their children because that position is supported by the best available science, and because the alternative is definitely not safe.

Secondly, according to your interpretation of Kant's categorical imperative it's perfectly ethical for no one to get vaccinated because everyone can act in that way. You may not like the outcome, but your gedankenexperiment satisfies the categorical imperative because everyone holds the belief and thus it is ethical.

Kant's categorical imperative is merely a way for a large percentage of the population to force their ethics on others. Largely because the primary way it is used is to justify policies rather than have policies stem from it. Since not everyone can agree that everyone should be vaccinated policies to vaccinate everyone are unethical according to Kant.

Government doesn't (or shouldn't) have the power to force me to do this. But there's nothing wrong with each individual in the community attempting to persuade those who don't want it.

By analogy: the government doesn't have the authority to endorse any religion, but I'm certainly free to tell you about mine (if I had one).

Vaccines don't necessarily grant immunity. They give you a 70%-85% chance to gain immunity. So even if 0 are left unvaccinated, 30% of the population has no immunity.

It is unlikely to infect a large portion of the population, but especially for vaccines which are only 70% effective, it's highly likely 1 or 2 others will get infected who were vaccinated but it didn't take. In addition to the 30% of people who do not have immunity, immunocompromised people often time can lose immunity to certain viruses based on their condition. They are the 1 or 2 people our society has chosen to be effectively infectable in spite of vaccination. That's why its very important everyone else gets vaccinated.

The likelihood of a huge outbreak is still relatively small, but you're wrong on the statistics of the small infection, as you'd see from a friend coming by or out to dinner with you or going to day care. Roughly 15% to 30% will get many of the diseases when "intensely exposed". The chance of a small outbreak is moderately large with 70% vaccines and even moderate lack of vaccinations.

Your argument, in addition to be attempted technical nitpicking which is wrong, is very dangerous as other posters have made. The effect of one additional unvac on a given population is extremely noticeable on small populations, such as groups of friends and daycares and businesses, aka the very places I suggested ostracizing people from.

I'm curious to know if there have been results that show what sort of percentages of vaccination are needed to be safe from specific diseases. I presume this will vary between diseases as well as demographics.

http://en.wikipedia.org/wiki/Herd_immunity

It wouldn't be right to ostracize people simply because their parents can't tell the difference between a stripper and a doctor and took medical advice from Jenny McCarthy.

http://www.ottawa.ca/residents/health/conditions/id_preventi...

Any parent decline for religious reasons.

And missing one vaccine because their parents are idiots isn't the point. Its the walking infection vectors who are the people who have absolutely no vaccines in them in are the issues.

As a father, some other part of me kicked in that wasn't very logical. This is much harder decision than it seems.

My mother in law shared with me her first-hand experience of 'watching-the-lights-go-out' in a healthy 3-year old minutes after she was vaccinated. It's not autism, and it's anecdotal evidence, but it made me dig deeper, and doubt any certainty on either sides.

Studies are NOT conclusive. Dozens of studies where done defending the use of mercury in amalgam fillings for example, and just now the dentist community is coming around to admitting that it does negatively impact patients' health. Years after many people were saying that, and were called naysayers.

I didn't vaccinate my son. It wasn't an easy decision. And I'm not certain of it. He will receive a shorter list of vaccines, on a longer less-stressful schedule than the one recommended by the govt.

Anybody who assumes certainty for either side of this argument hasn't given this enough thought imho

Vaccinations are important. End of story.

Furthermore vaccinating the most of the world is not going to happen until they are made strictly for all people and not for profit. Patenting medicine and vaccines and distributing it to only those who are "deserving" sound a bit off no?

In the U.S., though, we do actually have quite a lot of free vaccination clinics, and many people have health insurance that covers vaccinations. It's possible there aren't enough free clinics, and if studies show that a large % of people not being vaccinated are skipping it due to the expense, then that's something we should work on. But I don't believe that's currently the case--- a large proportion of the people skipping vaccinations could have had them completely paid for, either by their health-insurance plan, or via free vaccination clinics, but deliberately chose not to get them.

edit: Actually, are there good studies on the primary causes of non-vaccination? It'd be interesting to see estimates of the numbers of people who fall into categories like: 1) fear of autism/etc.; 2) fear of allergic reactions; 3) religious objections; 4) too expensive; 5) too inconvenient / never got around to it.

Eg.

http://www.scielosp.org/scielo.php?pid=S0042-968620080006000...

I honestly feel as a matter of public health it should be free. If it was someone I saw every day who alleged this reason, I'd take them to the doctor right then for the shots, paying for it.