03/18/2010 05:12 am ET Updated Nov 17, 2011

A Question of Harm -- The Legacy of Vaccination

The Age of Vaccines

In the early '60s, there were approximately 450,000 measles cases and an average of 450 measles-associated deaths reported each year in the United States [1] . The disease had been a killer for centuries, and at its peak an estimated 3-4 million persons in the United States were infected each year, of whom 400-500 died, 48,000 were hospitalized, and another 1,000 developed chronic disability from measles encephalitis. [2] Despite its ubiquity, measles was nothing to sneeze at.

Fortunately, in the face of this danger, American ingenuity once again rose to the occasion, and in 1957 a functional vaccine was produced. [3] Over the following years, a widespread regimen of vaccination was introduced across the country, and the results were nothing short of astounding. By the year 2000, measles had gone from millions of cases annually to being officially declared eliminated in the United States by the CDC. [4]

This is not an isolated result:

- Polio - from 21,000 annual US cases in 1952 to zero today. [5]
- Pertussis (Whooping Coung) - killed between 5,000 and 10,000 annually; now kills approximately 30 annually. [6]
- Smallpox - killed between 300 and 500 million people in the 20th century [7]; certified as completely eliminated by the WHO in 1980. [8]

Look at that last number one more time. Really. From up to 500,000,000 deaths in 100 years, to a planet where nobody will ever die from smallpox again. Ever. This is the legacy of vaccination.

Now, some people are looking to throw it all away.

Thimerosal - The Mercury Factor

Before the early 90s, the average citizen would likely never have heard of thimerosal. Invented by Morris Kharasch at the University of Maryland, and filed for a patent in 1927 [9], thimerosal has been used as a preservative and disinfectant in the health care industry for decades. One of its primary uses has been as a preservative in multi-dose vaccine formulae, where it is used to protect the vaccine batches against infection by Staphylococcus and other bacteria.

Thimerosal is approximately 50% mercury by weight, and metabolizes in the body into ethyl (as opposed to methyl) mercury. [10] Thimerosal is typically included in vaccines at 1 part in 100,000 to 1 part in 10,000, which is sufficient to clear out a wide array of potential infections in the vaccine. Standard vaccine doses for children under 35 months is .25 mL; for children up to 9 years, it is .5 mL. [11] With a thimerosal component of 50 micrograms per .5 mL, that works out to about 12.5 micrograms of mercury in the very young doses and 25 micrograms (the maximum considered safe) for vaccines administered to children up to age 9. [12]

Recently, the inclusion of thimerosal in vaccines has begun to cause concern amongst parents worried about the toxicity of mercury, and its effects on young children. There is even a belief among a small segment of the population that there is a connection between childhood vaccinations and autism, centered around the mercury in thimerosal. Although a 2003 study found that autism spectrum disorders increased both in places where thimerosal use increased (California) and decreased (Sweden and Denmark) [13], authorities in the United States were concerned enough that they began to phase out thimerosal-preserved vaccines. Because of this, today only one childhood vaccine in the United States - influenza, an optional vaccine - contains thimerosal. [14]

A Question of Harm

Nonetheless, the anti-vaccination movement has picked up steam in the past few years, and authorities now believe that pockets of unvaccinated children are forming. This is beginning to have deadly results, as old killers long eradicated from American public life - measles, pertussis - begin to once again strike children down with sickness, even death. [15] Tragically, despite both reduced vaccination rates and removal of thimerosal from childhood vaccines, autism rates continue to climb, indicating the link between thimerosal and autism likely never existed in the first place and making the rejection of vaccinations all the more senseless. [16]

In the end, it is a question of risk. The risk from diseases like measles, rubella, pertussis, diphtheria and more is well documented and deadly, and the tools for fighting them well understood and effective. By contrast, the causes of autism are poorly understood; indeed, almost all we know is that vaccination almost certainly is NOT the cause. To face having to trade dozens of powerful immunities in order to prevent the possibility of autism would be a difficult and unenviable choice; but when we understand that autism rates have continued to climb even in those who take vaccines without thimerosal or who take no vaccines at all, the conclusion is evident.

There is nothing more precious than the life of a child. It is both the right and the responsibility of a parent to follow up on your concerns about the health and welfare of your children. So please, don't take my word for it. Talk to your doctor. Read the studies. Ask the FDA or the CDC. And vaccinate your family. There is no more powerful or effective way of saving a life.


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