by Alicia M Prater PhD

Created on: October 02, 2007   Last Updated: July 07, 2011

Understanding the purpose of vaccination is important to assessing whether they are necessary. Vaccines are tools used in the prevention of disease. They were, and still are, developed as a means to prevent epidemics and outbreaks that can sicken, maim, or kill hundreds to thousands of individuals at a time by jump starting the immune system against the infectious agent. After decades of struggling with vaccination programs, many of these diseases have been nearly or completely eradicated in the United States (smallpox, polio, diphtheria). So some may ask, 'Without anyone being ill, why do we need the prevention?'

The answer is that no disease has been eradicated from the entire world, with the exception of smallpox, and children actually still get the diseases that no longer appear to be common. In fact, because of a lack of vaccination, whooping cough (pertussis) and measles are making a comeback in the United States and other developed countries, with outbreaks infecting thousands over the past few years. And these are just the so-called childhood diseases, there are a number of other diseases protected against by vaccination when a subpopulation is at risk, such as healthcare workers and Hepatitis B, and the elderly with influenza. Children, travelers, and susceptible adults in the United States still require vaccinations in order to keep the diseases from coming back en masse.

Essentially, vaccinations for common childhood diseases are still necessary in the United States as long as they have a presence in the rest of the world. Diseases like polio, measles, and diphtheria still ravage populations in some parts of the world. Measles made a comeback in the United States in 1990 due to the lack of vaccination of children in suburbs (due to conscious choice by their parents) and inner cities (due to lack of public health measures and health care). The disease was brought in by international travel and multiplied among populations with low vaccine compliance. Even if a disease is rare in the United States, this is a time of global travel and a virus or bacteria can easily travel into the United States, and once it enters an unvaccinated population - it spreads, and kills. This is also why it is important for adults to maintain their immunity from previous vaccinations by getting boosters throughout their life.

For all individuals, it is also necessary to vaccinate against disease not present in the United States when planning to travel to locales with endemic disease. Yellow fever, in particular, is a disease that Americans are not exposed to until they travel overseas. If a person were to travel without vaccination and become infected, they would then bring the disease to the United States, a population susceptible to infection. This could result in an epidemic. There are health care measures in place to prevent such a spread, but vaccination is the easiest and most cost-effective prevention measure, both individually and communally. There are also vaccines necessary for those in certain fields, such as the hepatitis B vaccine for health care workers exposed to body fluids and anthrax for military personnel who may be exposed to biological weapons.

Most people clear minor infections on their own, but there are vaccination schedules developed by the CDC to take into account susceptible populations and the severity of infections so that vaccinations can be properly targeted and used most effectively. The childhood vaccination schedule immunizes children prior to exposure, as they are a highly susceptible population for disease due to an undeveloped immune system.

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