American people believe in freedom of choice above all else, but not all Americans consider the effect that their choice has on those around them and the population as a whole especially in regards to vaccination and world health. When parents are deciding to vaccinate their children they tend to consider only what is best for their child, not what is best for the population at large which is unfortunate because the two are deeply intertwined.
Consider a simpler example: imagine you are a farmer with sheep. When you first buy your farm you vaccinate every sheep against all of the horrible diseases that are out there because you only want the healthiest sheep and you care about them. After a few years of vaccinating the population, major diseases have been eradicated and its time for lambing season. This year you decide that your sheep are healthy and thriving so there is no need to put the new lambs at risk by giving them the vaccine; your herd is healthy. The next year, the farm next to you goes out of business and you decide to absorb the herd into your own, they have all been vaccinated and you perceive no threat. What you do not see is that some of these sheep carry the disease into your farm and the next week an epidemic breaks out; it spreads quickly through all of the sheep you chose not to vaccinate who have never even been exposed to this disease and it kills most of the yearlings and then begins to infect the older sheep even though they have been vaccinated due to weaker immune systems. You lose a lot of sheep.
Much like the sheep in the previous example, children do not choose whether or not they get to be vaccinated and like the farmer, parents do not always perceive a threat to their child much less the population. In recent years more and more people are questioning whether or not to vaccinate their children and are relying on herd immunity to keep themselves safe from disease. The problem with this is that when the individual considers immunity they think only of themselves, they perceive the disease as something abstract and if everyone else is vaccinated then there is no way for it to spread and an extremely low chance of contracting it. As crazy as it may seem they are not the only person who is thinking this way but there is no way for them to know that. They rely on everyone else’s immunity but if everyone has the same idea then in the future there will be less and less of this “immunity” to rely on.
People are beginning to wonder where outbreaks of the measles and tuberculosis are coming from and they can look to the affluent and well-educated population who are relying on the immunity of others for the answer.