In the past, epidemics of serious disease were much more common than they are today.  During the late 1800s and early 1900s (at the same time that courts were regularly striking down economic legislation), courts had to decide whether governments could impose quarantines on people with contagious diseases and whether states could require vaccinations — especially for school children.  While the case law on the right to privacy was much less developed than it is today, there was some recognition of personal autonomy (the same concept of autonomy underlying the right to contract case law) and parental primacy in making decisions on behalf of their children.  The bottom line in these cases is that — when scientifically supported — quarantines and mandatory vaccinations could be appropriate.

In recent months, this well-settled law has run smack into a political movement that simply does not respect science.  This disrespect for science leads the same politician to rush to quarantine individuals with Ebola even though the quarantine policy may not be legally valid due to a lack of scientific support while opposing mandatory vaccinations which have a solid base of scientific support.

The science underlying mandatory vaccinations and quarantines share some basic ideas.  (Doc Jess can probably give a more detailed explanation than I can, but this is the lay/lawyer understanding of the basic science).

Diseases tend to be caused by one of two things — a virus or a bacteria.  A bacteria is a single-cell organism.  If you have a bacterial infection, the bacteria will multiply by stealing food away from the healthy cells (sometimes releasing a toxic waste that injures the host cells).  A virus is (at the simplest level) a piece of genetic material.  Like all genetic materials, a virus wants to replicate itself.  It achieves this goal by taking over a host cell, killing the natural genetic material in that cell, and reprograming that cell to reproduce the virus rather than host cells.  Eventually, the host cell is overloaded with viruses and bursts letting the new viruses free to attack neighboring cells.  As more cells fall prey to the virus, the body begins to show negative effects — some potentially permanent or fatal.

Each disease has a natural progression and spreads by a different way (e.g., airborne, insect bite, touch/sharing fluids).   The natural progression of a disease determines when the host (i.e. the sick person) is contagious.  Some diseases are contagious before any significant symptoms are noticeable.  Others are only contagious after symptoms are apparent.  This difference is significant for designing quarantine programs as a person only needs to be quarantined if they might be contagious.  Similarly, an airborne disease requires a different quarantine approach than a disease spread by contact.

The human immune system is designed to defend against diseases.  It does so by attacking potentially infections invaders.  Before the human body can adequately defend against an invader, the immune system must be able to recognize the invader and respond before the invaders.  The concept of vaccination is to introduce a dead or weakened version of the virus into the human body so that the immune system is prepared to respond if it ever faces a strong live version of the disease.

A proper vaccination system works in two ways.  First, for most people, vaccination leaves them with a strong enough defense that — even if they encounter the disease — their body will be prepared to kill the invader (either preventing the development of any symptoms or minimizing the symptoms).  Second, if enough people have developed an immunity to the disease, there are few potential hosts for the disease and those hosts are naturally scattered (reducing the chance of the disease spreading from the initial patient to others or even getting to the initial patient — frequently referred to as herd immunity)   It is this second aspect that is put at risk by the current hostility to vaccination.  When 90% of families in a school district have been vaccinated, it is very hard for measles or mumps or polio to take root.  As that number gets lower, the disease rapidly passes from one family to another.

As recently as 30-40 years ago, many diseases did not have a viable vaccines and everybody knew somebody who died from or had serious complications from measles, mumps, or polio.  Now, vaccination has made these diseases very rare (and have effectively made smallpox extinct), and people have forgotten why we need vaccinations.  Meanwhile, some Republican politicians are willing to play game with our children’s health.  Shame on them, and double shame on Rand Paul who as a doctor is supposed to know better.