Earlier today, the CDC released a report about the measles outbreaks that have been occurring across the country since the beginning of the year. (Hat tip to USA Today‘s Liz Szabo for this story.) I wrote a fair amount about measles in my book, and one reason measles outbreaks are so scary (and so difficult to contain) is that measles is the most infectious microbe known to man–it’s transmission rate is around 90 percent. It has also killed more children than any other disease in history.
If you’re skeptical about the correlation between measles vaccination rates and the spread of the disease, or about the danger deliberately unvaccinated members of the population pose to infants, you should check out the CDC’s figures. They’re pretty stunning:
* There have been 118 reported measles cases in the first nineteen weeks of the year — which is the highest number of infections for that period since 1996. That’s particularly noteworthy because, as the CDC points out, “as a result of high vaccination coverage, measles elimination (i.e., the absence of endemic transmission) was achieved in the United States in the late 1990s and likely in the rest of the Americas since the early 2000s.”
* Eighty-nine percent of all reported cases have been in people who’ve been unvaccinated. Almost 20 percent of that figure is made up of children who were less than a year old. That means they were too young to have received the first dose of the measles-mumps-rubella (MMR) vaccine, which is given once between the ages of twelve and fifteen months and again when a child is between four and six years old. Another twenty percent of the total number of reported infections were in children between the ages of one and four.
* Forty percent of the infections recorded so far this year have resulted in hospitalization — and 98 percent of the people who were hospitalized were unvaccinated. In its typically understated manner, the CDC noted that “nine [of the hospitalized patients] had pneumonia, but none had encephalitis and none died”– which is another way of saying that encephalitis and death are potential complications of serious cases of pneumonia.
The most significant factor in the spread of measles in the United States is the increase of pockets of the country where vaccination rates have declined below the level needed to maintain herd immunity`– and, similar to what occurred in the UK in the early part of the last decade, that decline can be traced back to the press-fueled panic sparked by anti-vaccine messiah Andrew Wakefield’s discredited, retracted, and possibly fraudulent twelve-child case study linking the MMR vaccine to autism.
Indeed, it’s striking just how many of the infections are clustered around Minnesota, where anti-vaccine activists have been for years targeting an immigrant Somali community…and where Wakefield has made multiple trips over the past several months:
Anyone curious about how quickly a series of small measles conflagrations can spread horribly out of control should check out the situation currently unfolding in France, which is in the third year of a nation-wide outbreak.^ In 2007, the number of reported cases in France was around forty. The next year, they jumped to six hundred…and they’ve been rising ever since. So far in 2011, there have been more than 6,400 infections in the country. Translated to a population the size of the US’s, that would represent a jump from 188 cases to more than 28,000.
The toll that would take on the nation’s health-care infrastructure is mind-boggling. Consider this: In 2008, a deliberately unvaccinated patient of “Dr. Bob” Sears caught measles while on vacation in Switzerland. That single infection ultimately resulted in a total of 12 cases…and the total cost of containing the outbreak topped $150,000.
` The beginning of this sentence had previously read, “The most significant factor in the spread of measles in the United States is declining vaccination rates.” As some readers have pointed out, the overall vaccination rates in the country have more or less stayed the same; the issue is the increase in individual communities where vaccine refusal has grown.
^ France also illustrates how the result of vaccine panics can be similar even when the roots causes are completely unrelated: A recent British Medical Journal story titled “Outbreak of measles in France shows no signs of abating” points out that “the publication in the Lancet in 1998 of the research article by Andrew Wakefield purporting to show a link between the MMR vaccine and autism had no significant effect on uptake of the MMR vaccine in France. The main vaccine controversy in France has centred on that against hepatitis B, and this has taken its toll on immunisation campaigns as a whole.”
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