CORRECTION: This column originally stated that the measles-mumps-rubella (MMR) vaccine contains mercury. It does not. The worry about the MMR shot causing autism concerns the live nature of the vaccine, not mercury. LiveScience regrets this error and any confusion it may have caused. The text below has been corrected.
In a world far removed from the daily perils of life 100 years ago, when families were large with the expectation that at least one child would die, more and more parents today are opting not to have their children immunized against diseases that can kill or handicap them.
As relayed in the Aug. 3 issue of the New England Journal of Medicine, an American girl visiting Romania who wasn't inoculated against measles brought the disease home to Indiana and spread it to 36 others at a religious gathering, nearly all of whom were also not inoculated. The parents had chosen not to inoculate their children for religious reasons and a perceived fear of the dangers of vaccines.
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Fortunately, although several patients were hospitalized, no one died.
Not so elsewhere in the world, where measles infects 30 million people each year, mostly children, and kills about 500,000 and sometimes as much as 10 percent of the infected in poorer regions, according to the World Health Organization (WHO).
Doctors triumphantly announced the elimination of measles in the United States in 2000. But the recent outbreak is not surprising. The virus that causes measles is only a plane ride away, particularly when we continue to let our guard down.
American children who are not vaccinated remain healthy for now because they are essentially freeloading on the herd immunity all around them. Their immediate environment is virus-free because everyone else is vaccinated and such diseases cannot spread.
Measles immunization is compulsory for all school children, and most of the public is immunized. Parents can skirt the vaccine requirement, however, by home-schooling their children; and most of children infected in the Indiana outbreak were indeed home-schooled.
Should vaccination rates fall below 80-90 percent, depending on the disease, outbreaks are inevitable—not just among the unvaccinated but also among adults whose immunity has weakened over the years. In the past, it was the hard to reach—poor communities or recent immigrants—who weren't immunized. Today it is the relatively educated middle and upper classes.
That the efficacy of vaccination is questioned despite such remarkable successes is startling. Smallpox is gone and polio is almost gone.
Misinformation spreads like...
Misinformation about vaccines on the Internet spreads faster than viruses. While there are some legitimate concerns, much of the anti-vaccine venom is simply false or misleading facts. Here are a few of the most repeated, starting with the one worry that's at least founded in science.
The measles-mumps-rubella (MMR) vaccine causes autism: The primary concern is that the live virus contained in the MMR shot can lead to intestinal problems, such as Crohn's disease, and subsequently contribute to the development of autism. The fear stems several small studies from the 1990s and, in particular, a 1998 article in The Lancet by Andrew Wakefield. Scientists conceded to the plausibility, and hundreds of millions of dollars have been spent researching this important and legitimate autism issue. Similar to the concern about electric power lines and leukemia, however, no connection has been found. Related to this is the concern that the vaccine preservative thimerosal, which contains ethylmercury, can cause autism. Thimerosal is not used in "live" vaccines, like the MMR shot, and actually has been removed from all childhood vaccines except for some flu shots. Nevertheless, large studies found no thimerosal-autism link.
Childhood viral diseases aren't that serious, and the vaccine poses greater danger: There's a bit of pretzel logic here. The risk of getting diphtheria, a major killer 100 years ago, is extremely low only because most people are vaccinated against it. The risk of side effects for some vaccines, such as whooping cough, or pertussis, appear high—about one in 20—but this is for mild reactions, such as controllable fever. Moderate symptoms, such as a very high fever, are seen in about 1 in 10,000 doses.
Make no mistake: Several reactions and death are real and tragic but extremely rare.
The primary childhood vaccines prevent death and mental and physical disability that were once commonplace as a result of polio, diphtheria, meningitis, hepatitis B and a host of other diseases, which remain endemic where immunization rates are low. I'll accept the argument that the chickenpox vaccine isn't that necessary, because only rarely does this disease kill and because the vaccine wears off by adulthood. But measles is not just the wholesome polka-dot-face disease lampooned in cartoons.
Polio and other viral diseases were on the decline before the introduction of vaccines: That's not quite right. The emphasis on hygiene in the late 1800s did lower the rates of many diseases. But it was vaccines that brought radical reductions and regional elimination of diseases.
Polio rates actually increased in the 1950s after inoculation: That's not quite right, either. Some communities did see an increase, as much as 500 percent (which sometimes simply meant a jump from one case to five cases). But this is how polio works, in spurts and outbreaks. Let's extend this logic. If the polio vaccine causes more polio, the disease today would be pandemic. Instead it is nearly eradicated.
Better nutrition has eradicated viral diseases, not vaccines: Polio and small pox aren't scurvy, where vitamin C can be a quick fix. Better nutrition indeed leads to a stronger immune system; and only about 1 percent of children with measles in well-nourished countries will die, as opposed to 10 percent in sub-Sahara Africa. But even the healthiest of people can contract a viral disease.
You want a cause-and-effect association? Great Britain thought pertussis disappeared and cut back on immunization in 1974. By 1978 there was an epidemic of more than 100,000 cases and 36 deaths. Same goes for Sweden and Japan. Diphtheria immunization fell with the break up of the Soviet Union. The number of cases rose from 839 in 1989 to nearly 50,000 in 1994, including 1,700 deaths, according to the WHO. On the flip side, we have success stories. Since the introduction of the Hib (Haemophilus influenzae type b) vaccine in 1990, Hib rates have fallen 99 percent in the United States.
You can take potshots at the shots, but society as a whole greatly benefits from them.
Christopher Wanjek is the author of the books “Bad Medicine” and “Food At Work.” Got a question about Bad Medicine? Email Wanjek. If it’s really bad, he just might answer it in a future column. Bad Medicine appears each Tuesday on LIveScience.
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