Medicine For People!
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Vaccination: A Heads-Up For Your Immune System
- Your Immune System has Resources to Spare
- Vaccination: Preventing Disease for over 500 Years
- Vaccination Controversy
- Correlation is not Causation
- Coming Soon
Your Immune System Has Resources to Spare
Your immune system protects you from hundreds of thousands of different organisms. (We think it has a capacity in the millions.) Take the mononucleosis virus. If your immune system hasn't seen it before, you'll get symptoms for a few weeks or months. But mono reliably disappears as your own immune system engineers new antibodies to eliminate it and prevent it in future.
Of the millions of kinds of viruses, only a few pose a serious threat to our immune systems. These include smallpox, HIV, Ebola, whooping cough, and others. So why not give your immune arsenal a silver bullet: a vaccination.
Vaccination: Preventing Disease for over 500 Years
Some 500 years ago, the Chinese of the Ming Dynasty noticed that people who milked cows usually caught a temporary rash called cowpox. After that, they rarely caught smallpox. This was a pretty easy correlation to figure out, because smallpox has a distinctive rash and leaves behind a lot of dead bodies. So the Chinese scratched the cowpox scabs into the skin of those not lucky enough to work in a dairy.
The Persians and the Turks tumbled to this association somewhat later, and we in the West followed along in the 1700s. We developed the smallpox vaccination, and everyone got it. By the 1970s, the smallpox immunization was history, along with smallpox.
Unfortunately, most vaccines are neither 100% effective nor 100% safe. The smallpox prevention strategy used in China in the 1500s killed about one person in 100. Risky, but not as much as smallpox, which at that time killed one person out of three.
Years ago I paid a lot of attention to immunization controversies. I spent hours finding and reading the important studies, teasing apart the details and chasing down the claims of people who sincerely distrusted vaccination. As I've said, there are pluses and minuses to immunization, but generally many more benefits. The anti-vaccine folks seemed to see only conspiracies. The current anti-vaccine hero, a doctor named Andrew Wakefield, turns out to have faked his autism data with the purpose of discrediting the MMR (Measles, Mumps and Rubella) so he could sell his own, supposedly safer, vaccine.
Let's examine the history of one particular real downside, the old vaccine for whooping cough, known to physicians as pertussis. The original vaccine caused fever and the occasional seizure. Doctors don't like to make patients feel worse instead of better, even temporarily. Furthermore, these side effects generated dramatic overreaction by the media and gave more fuel to the anti-vaccine movement.
Yet when we looked at the numbers, there was just no alternative. Pertussis kills kids. Diagnose as quickly as you can, treat as aggressively as you can and it still kills otherwise healthy children.
Source [http://spock.fcs.uga.edu/cfd/cdl/docs/vaccines_exemptions.pdf ]
This graph shows the number of cases of pertussis in Japan between 1955 and 1995. When the pertussis vaccine was introduced in the 1950s, pertussis was prevalent and pertussis deaths (not illustrated here) were frequent. The old vaccine, imperfect as it was, reduced cases to a minimum. In Japan the case count was extremely low in the late 1960s and the death rate was zero. But along came Japan's anti-vaccination movement. (See the gray bar.) Pertussis vaccination rates fell and pertussis deaths reappeared, reaching a high of 41.
Around 1978, a much cleaner vaccine became available. The vaccine was much better tolerated, vaccination rates rose, and pertussis deaths again fell to zero.
You can see examples from other countries in the Lancet article cited above. This situation was similar around the world.
Occasionally we read in the news of someone injured by a seat-belt or an air-bag. Just as with vaccinations, work goes on to improve those technologies. But let's not give up on the preventing injuries and death from auto accidents and viral infections!
Correlationis not Causation
Every day in the United States, about 1200 people die from a heart attack. As a thought experiment, let's divide the east side of the United States from the west. On the east side of the line, everyone gets a flu shot. On the west side, everyone watches a Bugs Bunny cartoon.
The next day, 1200 people have their heart attacks. On the east side, some of those 600 aggrieved families might wonder about Granddad's flu shot. On the west side, no aggrieved families will be wondering about the Bugs Bunny cartoon. Yes, this is a ridiculous example, and yes, the real-world safety analyses are much more nuanced, but the general idea is spot on.
Vaccination is not perfect. No one who studies it makes that claim. Work goes on every day, around the world, to improve the process. This massively improves our survival in the natural conflict between us and certain micro-organisms. Because of immunization, we just don't see the illness we would otherwise see.
As a final example, routine pre-pregnancy care includes vaccination against German measles. No big deal, except when it doesn't happen, and you can see what that looks like here.
Immunization is about as exciting as buckling your seat-belt. If you need motivation, please watch the video above or read about smallpox, pertussis, diphtheria, rubella, polio and tetanus on Wikipedia.
In a coming newsletter, I'll address the newer quadrivalent (4 different strains of influenza) as well as the older trivalent (3 different strains) influenza virus. As you know, we can approve of something and yet keep our critical eye. In that spirit, I'll illuminate the economics and marketing hype of the new high-dose influenza vaccine.
===With appreciation to Mary Davies, guest editor.
Image licensed per http://commons.wikimedia.org/wiki/File:Typhoid_inoculation2.jpg#/media/File:Typhoid_inoculation2.jpg
Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington.