Showing posts with label Measles. Show all posts
Showing posts with label Measles. Show all posts

Thursday, May 8, 2014

The autism vs vaccines controversy

In 1998 an article published in the British Journal The Lancet claimed it found a causal connection between the MMR vaccine and autism. Although that article was widely disputed and later retracted, it has left behind a significant following, leading many parents to refuse MMR vaccination for their children. The anti-vaccine groups also stressed on the use of mercury-based preservative Thimerosal in vaccines as a suspected culprit. As a result the government has gradually removed it or reduced it to trace amounts in all vaccines in 2001, in spite of no scientific proof of its possible link to incidence of autism. As explained on the CDC website;

"Over the years, some people have had concerns that autism might be linked to the vaccines children receive. One vaccine ingredient that has been studied specifically is thimerosal, previously used as a preservative in many recommended childhood vaccines. However, in 2001 thimerosal was removed or reduced to trace amounts in all childhood vaccines except for one type of influenza vaccine, and thimerosal-free alternatives are available for influenza vaccine. Evidence from several studies examining trends in vaccine use and changes in autism frequency does not support such an association between thimerosal and autism. Furthermore, a scientific review by the Institute of Medicine (IOM) concluded that "the evidence favors rejection of a causal relationship between thimerosal–containing vaccines and autism." CDC supports the IOM conclusion that there is no relationship between vaccines containing thimerosal and autism rates in children.
The IOM also recently conducted a thorough review of the current medical and scientific evidence on vaccines and certain health events that may be observed after vaccination. It released a report in August 2011 on 8 vaccines given to children and adults that found the vaccines to be generally safe and serious adverse events following these vaccinations to be rare."

The 2012 National Immunization Survey  found that about 90% of children aged 19 to 35 months completed recommended vaccinations and less than 1% received no vaccines at all. But it also highlighted the fact that rates are varied by states and regions therefore leaving some areas vulnerable to outbreaks of measles and other vaccine preventable diseases. The resurgence of measles and whooping cough (Pertussis) in recent years after decades of almost complete extinction could possibly be the distressing consequence of an increasing number of parents refusing the MMR vaccine on grounds of its possible association to autism. 

As explained by Puneet Kollipara in The Washington Post article How the anti-vaccine movement is endangering lives (May 5, 2014).

A measles outbreak that struck a Texas megachurch community late last summer sickened 21 people. And just recently, at least 16 people got sick during a measles outbreak in Ohio. In fact, the Centers for Disease Control and Prevention recently reported 13 measles outbreaks so far in 2014 -- the most since 1996.

According to an article in JAMA News;

Overall, among 140 US residents who acquired measles, 117 (84%) were unvaccinated, and 11 (8%) had unknown vaccination status. Of those who were unvaccinated, 92 (79%) had philosophical objections to vaccination, and 15 cases (13%) occurred among infants younger than 12 months who were not eligible for vaccination.


Besides leading to prevention and saving lives, these vaccines are also economically beneficial, as pointed out by Kuneet Kollipara;

A new study from CDC researchers led by Anne Schuchat analyzed what happened to disease rates as childhood vaccination rates increased starting in the early 1990s. The researchers used these findings to model the resulting effect over the kids' lifetimes. In the analysis, the researchers factored in most routine vaccines recommended for children below age 6 (among them the MMR and whooping cough vaccines). Their findings: Routine childhood vaccinations given between 1994 and 2013 will save 732,000 lives and prevent 322 million cases of illness and 21 million hospitalizations over the course of the children's lifetimes. 

In 2009 alone, the researchers determined, each $1 spent on vaccines and their administration yielded $10 in benefits to society. And the vaccinations from 1994-2013, the researchers found, will save society a net $1.38 trillion, both directly (by reducing health expenses) and indirectly (via the economic activity that is saved from avoided illnesses). That's almost 10 percent of the U.S. economy's gross domestic product.

In the end vaccines may not be without fault but there is no clear cut evidence to their causal link to autism. And they are definitely effective and save lives if given to a significant percentage of the population.



References:
How the anti-vaccine movement is endangering lives (The Washington Post-May 5, 2014).