Despite the obvious benefits of vaccination, thousands of parents are now refusing to immunize their children due to concerns regarding vaccine safety.

Take a walk through the grounds of any old cemetery and you will find the graves of a remarkable number of young children. Throughout history, disease — most notably measles, diphtheria, smallpox, polio, pertussis and various forms of influenza — routinely killed and maimed countless children.


Vaccines changed everything.


The creation of the vaccine is arguably the greatest medical achievement in human history. Mothers were once told not to count their children until they’d had smallpox. Today, smallpox no longer exists anywhere on earth. In the U.S., diphtheria claimed 15,000 lives annually, measles killed hundreds and caused thousands of birth defects, and polio paralyzed or killed with impunity.


Thanks to vaccines, these diseases are now virtually nonexistent.


Though vaccines provide individual protection, widespread vaccination also confers a benefit to susceptible community members through what is known as “herd immunity.” When vaccination rates reach 85 to 95 percent within a given population, outbreaks of many infectious diseases become impossible since most of the population cannot contract a particular illness or pass it on to others.


Despite the obvious benefits of vaccination, thousands of parents are now refusing to immunize their children due to concerns regarding vaccine safety.


The current trend can be traced to a 1998 study by Dr. Andrew Wakefield that suggested a link between the MMR (measles-mumps-rubella) vaccine and autism. The report generated widespread media coverage and prompted the creation of dozens of anti-vaccine advocacy groups.


Many supporters of holistic and alternative medicine soon began to theorize that the mercury used in a vaccine preservative called thimerosal was triggering myriad illnesses in children. As a result of the controversy, immunization rates began to drop. While overall rates remain high, some local communities within the United States have immunization rates as low as 50 percent.


The results have been predictable.


In 2008, an unvaccinated 7-year-old boy contracted measles while on vacation and exposed 839 people on the trip home. In 2009, a single intentionally unvaccinated 11-year-old boy contracted mumps and subsequently infected more than 3,500 in New York and New Jersey.


California’s current pertussis epidemic — its worst since 1955 — has infected 4,200 and claimed the lives of nine infants. Since all of those who died were too young to be vaccinated, they were reliant on herd immunity for protection.


While the growing fear of vaccines is evident, justification for such fear is not.


Autism is a developmental disorder that leaves those affected with difficulty communicating and interacting with others. There is no known cause and there is no cure.


Because some children appear to regress into autism coincident with the commencement of their regimen of childhood vaccinations, some argue that their autism was caused by the vaccines. However, correlation alone does not imply causation. The fact that two events occur together doesn’t mean that one was caused by the other; a rooster may crow at dawn, but that doesn’t mean the rooster causes the sun to rise.


Sorting out cause and effect while wading through a complex sea of variables is never an easy task, but additional evidence is available for consideration:


· Dr. Leo Kanner, the first person to describe autism in children, noted that some children appeared to be normal before later regressing at about age 2. Kanner recorded his observations in 1943, well before most of today’s standard vaccines were administered.


· Methylmercury is a known neurotoxin, but there is no scientific evidence linking it to autism. The vaccine preservative thimerosal includes ethylmercury, the effects of which are not fully understood.


Regardless, thimerosal was eliminated from vaccines as a precautionary measure in 2001. If thimerosal was causing autism, reported cases of autism should have dropped after 2001. They did not.


· Autism rates began to rise at about the time today’s multiple dose vaccines became the norm. However, 40 years ago, most children found to have a broad range of learning and/or communicative disabilities were frequently given the generic diagnosis of “mental retardation.”


Since then, the definition of autism has broadened considerably and diagnoses of mental retardation have simultaneously decreased. The inclusion of previously undiagnosed children and some level of diagnostic substitution account for at least a portion of the increase in the rate of autism diagnoses.


· Andrew Wakefield, author of the landmark study linking vaccines and autism, based his research on a sample of just 12 children. A subsequent investigation revealed that he falsified data and failed to disclose that he conducted his research after being paid thousands of dollars by lawyers who were preparing a lawsuit against vaccine manufacturers.


The British Medical Council found that Wakefield “acted dishonestly and irresponsibly” and revoked his license to practice medicine. The medical journal that originally published Wakefield’s report issued a retraction earlier this year.


· On the basis of dozens of scientific studies around the world, the FDA, the CDC, the Institute of Medicine, the American Academy of Pediatrics, and the World Health Organization have all reported that there is no causal relationship between vaccines and autism.


Despite the abundance of evidence to indicate that vaccines do not cause autism and are far safer than the diseases they prevent, the vaccine controversy persists. Why?


Parents often feel guilt when their children suffer, regardless of whether it is warranted, and a diagnosis of autism can be devastating. The ability to allocate blame elsewhere, to explain the inexplicable, is an appealing option.


 Once information becomes available on the Internet — good or bad, right or wrong — it is there forever. Millions looking for answers conduct research at the University of Google and simply choose to focus on the information they want to believe rather than what is believable.


Like many successful things, the benefits of vaccines are largely taken for granted. Many of us have no idea what life was like before vaccines. There is no good reason for us to find out.


Read more from Matthew Casey at matthewcasey.net.