So. Vaccines. People are having trouble keeping separate matters scientific and ethical and moral. Let’s attempt a classification.
Scientific Vaccines protect against disease.
Disease The etiologies of diseases are understood at various levels. Measles is very well known, the human papillomavirus less so. The prognosis for any disease is variable and depends on patient characteristics. The same disease, say, flu, can range from annoying to deadly depending on the person. The exact course of a disease is usually difficult to predict for any individual.
Vaccines The efficacy of a vaccine depends on the drug itself, the disease, and the characteristics of the person receiving it. Allergies to components of vaccines are not uncommon. Not everybody receiving a vaccine is immunized, but by far most are. The efficacy rate varies by vaccine. Vaccines can cause side effects or allow entry of other diseases. For example, the flu vaccine depresses the immune system increasing the chance of contracting other diseases. The side effects also depend on patient characteristics: not every person will suffer the same side effects nor suffer to the same degree. For common vaccines such as MMR, the side effects are well studied and the risk for most is minimal. For other vaccines, such as Gardasil for HPV (an important case), less is known. There is always room for questioning, of course, but decisions should not be changed until any new evidence is solid.
Not every person should get every vaccine. The CDC maintains a useful list of the kind of people who should not receive various vaccines. For instance, pregnant women should not get the adenovirus vaccine.
Autism as side effect There is no substantial, reliable evidence showing how the components of any vaccine cause autism. There are many guesses, but all, so far as I can see, fall far short of plausible. This does not argue that biological causes should not be investigated. Perhaps they should. But the investigations must be “bench” style and not statistical. The possibility of false alarm, especially when using classical (frequentist or Bayesian) statistical methods is huge.
Tracking side effects The main problems are (1) an increase in “awareness”, leading more people to be examined for the side effects and other diseases, and (2) an expansion in the criteria for side effects and other diseases; more marginal cases are being diagnosed. Autism in particular is being checked more frequently and the criteria for its presence have expanded.
Herd immunity If everybody but you has been immunized for a disease, and the only potential carriers of the disease are humans, then you are very unlikely to develop the disease. The chance is not zero because not all vaccinated people will develop immunity. As more people around you are unvaccinated, the greater the chance you will contract the disease—even if you yourself have been vaccinated, because the vaccine might not have “took” or it “wore off” (think about “boosters”). Still, most common vaccines are known to be extremely effective. If the carrier of the disease is other than humans, and you yourself are vaccinated and it “took”, then it doesn’t matter whether those around you are vaccinated or not, you will not contract the disease.
Moral Science is not ethics nor can any scientific fact answer any moral question, though these facts might be helpful to any decision.
To vaccinate or not Every individual must balance the rewards of protection with the risk of side effects and changes to their immune system. Your risk-reward criteria will differ from another’s. There is no scientifically determined optimal; such a thing is impossible. You must decide for yourself and for those over whom you are responsible. Many misinformed people will base their decisions on incorrect information. But only puritans insist life should be perfect (and directed by experts). Every unvaccinated person must understand they have a very small chance of infecting others (for human-born diseases) who have been vaccinated but whose vaccines did not “take” or “wore off.” The unvaccinated person can also easily infect other unvaccinated persons (for human-born diseases only). There is a balance between watching out for yourself and caring for others.
Forced vaccinations That balance becomes important here. Should the government legally force parents to immunize their children? For every possible vaccine? This would set the precedent of allowing the government to dictate the healthcare of children. To some extent this already occurs, of course, but many vaccines are not life-and-death. And some are not necessary, and again, the risks of deleterious effect of some vaccines will outweigh any benefit (allergies, pregnant women, etc.). The government will soon begin the argument, weak as it is, that since they are paying for your healthcare they have a right to insist on vaccines. Saves money, you see. Money often trumps morals. But then the government will fell emboldened to also disallow you pop over a certain size for the same reason—and God knows what else. All experience proves the counter-argument is not a slippery slope.
Some people refuse vaccinations on religious grounds. The government, forbidden to encroach upon this area, will argue that the “greater good” demands it. The constant danger is a utilitarian (i.e. money) interpretation to that phrase.
The balance is between personal and religious freedom, the right for families, especially parents, to be superior to government, and the changes to society that comes with this freedom when some diseases might be particularly virulent.
Behavior There is no need for Gardasil if you (or your children) if they are going to be celibate or monogamous. The same would be true if there were a vaccine for HIV. Having protection from some sexually transmitted diseases would encourage promiscuity and open individuals to other dangers. This also changes society.
There. This isn’t everything, but I think most major items are covered. What have I missed? Each individual vaccine-disease-person requires its own discussion.
You and yours are vaccinated against disease X. Suppose that vaccine to be 100% effective. You and yours will then not develop X. Now another family may decide against not vaccinating for X. They are then susceptible; they might contract X. If X is transmitted by humans, it is from other non-vaccinated humans from whom they’ll get X. If X is transmitted by animals, it makes no difference whether any other person was vaccinated.
Now why would you insist that others are coerced into receiving a vaccination? It is true that as the proportion of non-vaccinated people increase, the greater the number of people who might contract X, and the easier X can spread if X can be spread via humans. But, still, you and yours will not contract X.
What you are doing in insisting on coercion is forcing people to do what they do not want “for their own good” (“What about the children!”), and not your direct good. There is an indirect benefit to you in that it is not good that more of your fellow citizens will fall ill. It is far from clear where to draw the line. That depends on how virulent X is and so forth, and it depends on how the vaccine was formulated as was pointed out in comments and in the linked autism article above. There is a difference between flu and smallpox.
Of course, we have to modify the argument assuming the vaccination is not 100% effective. See Katie’s comment below. This premise, ceteris paribus, is in the direction of favoring coercion, but it is not decisive.