Dear Mrs. Colasanti,
After talking with you on the phone the other day, I decided to look into the link between autism and vaccines. As I had expected to find, studies have show that there is no causal link between the two. In fact, if you use google to search "autism vaccine" most of the sources that say that there is a link base their information on sloppy investigative journalism. If you use Google scholar (which only searches research through citations, authenticating the research), you will find articles like the one I've listed below. Often what the media does is interview parents of children with autism... while scientific researchers observe trends and do statistical analyses. You mentioned that one out of 150 children have autism. Below I've copied an article published by USA today which has as its catchy title "Autism disorders affecting 1 in 150." This is higher than earlier estimates of 1 in 166. Below that I've attached an abstract from a reputable medical journal (JAMA Journal of the American Medical Association).
This is how vaccines work:
1. There is an infectious disease that causes pain and suffering (the vaccine suspected in the autism case is the MMR (measles, mumps, and rubella) vaccine which 6 years ago contained mercury compunds)
2. There are always people with compromised immunity, so some people will not get vaccinated
3. If these people get sick, and others around them are vaccinated, the disease is confined to that person
4. If the community is not vaccinated and someone from the community gets the disease, we have a big problem
5. Now, with increased travel between countries, this is even more the case.
Dangerous thinking:
1. There is no scientific evidence whatsoever (even statistically... meaning that between surveys of children not vaccinated vs. vaccinated there is no significant difference in number of autism rates) that vaccines cause autism
2. Autism rates are apparently increasing (this is expected because we're getting better at diagnosing autism.. but sure, autism is probably increasing, though most likely not at such an alarming rate)
3. So, now people are looking for reasons for the increase in autism rates. This is very important, because we really don't want more children to develop autism if it is preventable. However, IT IS EXTREMELY DANGEROUS TO BLAME VACCINES and discourage parents from having their children vaccinated. (Please see the last article on whooping cough/pertussis in Boston.)
4. I feel sorry for your friend whose child is autistic...
5. But think about it this way, the reason that the vaccine is important for children is because children have weaker immune systems. It is likely that parents unknowingly transmit virulent strains of diseases to their children because of this.
Autism disorders affecting 1 in 150
http://www.usatoday.com/news/health/2007-02-08-autism_x.htm
Earlier estimates placed the rate at 1 in 166 children. But Catherine Rice, lead author of the analysis released Thursday by the U.S. Centers for Disease Control and Prevention, says the previous estimates were based on smaller studies, some from other countries, using different study methods.
The largest U.S. study of childhood autism to date has found that about 1 in 150 have the disorder -- a higher prevalence than previous national estimates, the Associated Press reports.
The autism rate was about 6.6 per 1,000 in the new study, which is based on data from 2002. The report was released today by the U.S. Centers for Disease Control and Prevention. Last year, the agency had estimated the rate was about 5.5 in 1,000.
The study does not, however, definitively answer whether autism is increasing. "We can't make conclusions about trends yet," because the study's database is too new, said Catherine Rice, a CDC behavioral scientist who was the study's lead author.
In materials posted online by CDC, the researchers write that: "A common explanation for increases ... over time has been that changes have occurred in the level of community and professional awareness about the symptoms" and that autism diagnoses are being applied to a wider range of symptoms.
Advocates for people with autism say the results should help them push for more services. The findings may further stoke the impassioned debate over causes: Some blame thimerosal, a mercury-based preservative that was used in infant vaccines up until six years ago. Scientists concede that they don't know the cause but say the science doesn't support a link to vaccines.
For the new CDC report, researchers drew on information gathered in 2000 and 2002 by a multistate surveillance network on 8-year-olds who were identified as having an autism spectrum disorder (ASD). The category includes autism, PDD-NOS (pervasive developmental disorder not otherwise specified) and Asperger's disorder. All are marked by problems with language and communication and often are accompanied by repetitive or unusual behaviors. ASDs begin before age 3 but may not be diagnosed until later.
Researchers focused on 8-year-olds because most children with such disabilities will have been identified by that age, Rice says.
The 2000 study, which examined children who were born in 1992, involved sites in six states and 1,252 children with ASDs. The prevalence averaged 6.7 children out of every 1,000.
The 2002 study, which focused on children who were born in 1994, involved 2,685 with ASDs at sites in 14 states and found that autism prevalence ranged from a low of 3.3 in 1,000 children in Alabama to 10.6 in 1,000 in New Jersey. The overall average was 6.6 in 1,000 children, or about 1 in 150.
Estimates differ because ASDs vary and some states have better diagnosis and tracking, Rice says.
Peter Bell, president of Cure Autism Now, says the report is "confirmation of our worst fears, and that is that autism is on the rise. Every two or three years, we're given an estimate that is higher than the previous one."
CDC Director Julie Gerberding said in a statement that it's still unknown whether there's an actual increase in autism or just better studies. "We do know, however, that these disorders are affecting too many children," Gerberding said.
States facing rising autism rates have struggled to provide services. Rice says the new information can be used by communities to help plan for the future needs of these children. "We know the best outcomes come when kids are identified early," Rice says.
The revised estimates will "increase awareness and hopefully get legislation to follow that will give services to those with autism," says Marguerite Colston of the Autism Society of America.
Association Between Thimerosal-Containing Vaccine and Autism
http://jama.highwire.org/cgi/content/abstract/290/13/1763
JAMA. 2003;290:1763-1766.
Context Mercuric compounds are nephrotoxic and neurotoxic at high doses. Thimerosal, a preservative used widely in vaccine formulations, contains ethylmercury. Thus it has been suggested that childhood vaccination with thimerosal-containing vaccine could be causally related to neurodevelopmental disorders such as autism.
Objective To determine whether vaccination with a thimerosal-containing vaccine is associated with development of autism.
Design, Setting, and Participants Population-based cohort study of all children born in Denmark from January 1, 1990, until December 31, 1996 (N = 467 450) comparing children vaccinated with a thimerosal-containing vaccine with children vaccinated with a thimerosal-free formulation of the same vaccine.
Main Outcome Measures Rate ratio (RR) for autism and other autistic-spectrum disorders, including trend with dose of ethylmercury.
Results During 2 986 654 person-years, we identified 440 autism cases and 787 cases of other autistic-spectrum disorders. The risk of autism and other autistic-spectrum disorders did not differ significantly between children vaccinated with thimerosal-containing vaccine and children vaccinated with thimerosal-free vaccine (RR, 0.85 [95% confidence interval {CI}, 0.60-1.20] for autism; RR, 1.12 [95% CI, 0.88-1.43] for other autistic-spectrum disorders). Furthermore, we found no evidence of a dose-response association (increase in RR per 25 µg of ethylmercury, 0.98 [95% CI, 0.90-1.06] for autism and 1.03 [95% CI, 0.98-1.09] for other autistic-spectrum disorders).
Conclusion The results do not support a causal relationship between childhood vaccination with thimerosal-containing vaccines and development of autistic-spectrum disorders.
Author Affiliations: Danish Epidemiology Science Centre, Department of Epidemiology Research (Messrs Hviid, Wohlfahrt, and Dr Melbye) and Medical Department (Dr Stellfeld), Statens Serum Institut, Copenhagen, Denmark.
Whooping cough makes a comeback
It sounds like something straight out of Dickens, closer to 1804 than 2004 -- a rattling, breath-robbing, rib-cracking cough, symptoms that linger for months, loss of sleep and weight.
The diagnosis -- pertussis, better known as whooping cough. At one time, public-health specialists had figured it was destined for extinction in the United States, just like polio and smallpox. But it's still here, six decades after vaccinations for the bacterial illness became routine -- a testament to the hardiness of infectious diseases."The bad news is that this disease is not gone," said Dr. Ken McIntosh, an infectious-disease specialist at Children's Hospital Boston. "I certainly have seen people with it, and they're miserable. And they're making everybody else in their lives miserable, and they're quite contagious. So it's not a nice disease to have."
The Centers for Disease Control and Prevention received reports of 11,647 cases of pertussis last year, compared with 1,707 in 1980 -- when the disease seemed to be dying out.
So, what explains the upsurge? And is it a true increase -- or a reflection of better reporting and testing?
Years ago, when pertussis was pervasive, children were regularly exposed and developed natural immunity.
"When the vaccine was licensed in the late 1940s and early 1950s, we saw a real drop in pertussis," said Dr. Susan Lett, medical director of the immunization program at the state Department of Public Health. "That was because all the adults at that point had had pertussis as kids, and their children were getting vaccinated, and so we saw a steep decrease."
In effect, the bacteria had no easy targets left.
But as the vaccine came into wider use, an important shortcoming was identified: The shot's effectiveness wanes within five to 10 years.
"What happened was that people at that time were so much in appreciation of the benefits of the vaccine that they did not think about the limitations," said Dr. Trudy Murphy, a medical epidemiologist in the CDC's National Immunization Program.
Doctors considered giving adolescents and adults another round of shots, but it turned out that side effects from the vaccine were amplified in older recipients. So that ceased to be an attractive option.
The result: Even though millions of US children have been immunized against whooping cough, the eroding effectiveness of the shot leaves them vulnerable to infection as they enter adolescence.
And, with the passage of time, there are fewer and fewer living Americans who were exposed to the bacteria when it was commonplace, meaning fewer people have natural immunity. The consequence, Lett said, is a "growing pool of susceptibles" -- more people whom the bacteria can successfully attack.
But McIntosh said the reported increase more likely reflects doctors being diligent about alerting health authorities to outbreaks, as well as improvements in laboratory tests used to confirm the disease.
"People are recognizing it more," McIntosh said, "and that's a good thing."
Nowhere is it recognized more than in Massachusetts. The state recorded about 1,700 cases of whooping cough last year -- one of every seven cases reported in the nation.
That doesn't necessarily mean we have more cases here. It's more likely proof of the state's aggressive testing for the disease, which began in the 1980s.
When pertussis kills, which is rare (19 Americans died in 2003), its victims are almost always infants.
Babies start getting immunized against pertussis when they are 2 months old, with another shot at the age of 4 months, and a final inoculation at 6 months.
"So what we really worry about is the 16-year-old who has pertussis, and it's unrecognized, and then the teenager baby-sits an infant younger than 6 months," said Dr. Alfred DeMaria, the state's director of communicable disease control.
Infants are especially susceptible -- and can become far sicker -- because their capacity to battle disease has yet to mature.
In anyone, whooping cough can cause significant discomfort, with dramatic bouts of coughing interfering with sleep and producing fits of vomiting.
And the effects are persistent: Studies have shown that 62 percent of adults with pertussis are still coughing three months after symptoms first appear.
Two drug companies --
The new formulations are less potent than the shots given to infants, and drug company trials suggest they don't deliver the side effects that doomed earlier boosters.
"It is so important to express to people the importance of vaccination," said Lisa Rae, whose son, Kyle, contracted pertussis as an infant in suburban Philadelphia. "I remember stories my Mom told us about whooping cough. This wasn't anything we ever expected."
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