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| Colored electron micrograph of a dendritic cell |
Scientists don't lie about such things; it's not in their interest at all. Their findings? "We found no statistically significant increased risk for the outcomes studied". They checked for the "life-threatening disabilities" mentioned on the first site and did not find them. They mentioned them because they checked for them, not because they found them as the alarmist site implies. What they did find were 5 cases of blood-clotting (venous thromboembolism; VTE) among 600,000 women studied (five in six-hundred thousand!) and all of these women were at high risk for VTE anyway, due to smoking, obesity, coagulation disorders etc. So yes, the HPV vaccine is safe as well. Only time will tell whether it will really protect against cervical cancer, though. It only prevents infection against 4 out of 30-40 strains of HPV, although these do include the ones responsible for 70% of the cases of cervical cancer.
Now that we have all that covered, I want to discuss how vaccines actually work. How does a vaccine make you immune to a disease and why should you have your baby vaccinated? Shouldn't a healthy diet of mother's milk and fruits later on be enough to protect your precious child? The key to understanding vaccination, or immunization, is the dendritic cells (see top left).
Dendritic cells are the first line of defense against anything invading your body that doesn't normally belong there. They're just tiny little cells and there aren't that many of them, but they do get around. These little cells are constantly on the prowl through your skin, the lining of your gut and well, all those places the inside of your body is likely to meet the outside world (you can use your imagination). They just spread their little tentacles everywhere and sample the environment, that's what they do all day, every day.
In the figure below I've illustrated what happens when a dendritic cell, on patrol in your skin, encounters an antigen (that is: a vaccine). In the left panel, the dendritic cell encounters just the antigen and is intrigued. In the right panel, the antigen is given with an adjuvant, an addition to the vaccine, that resembles a molecule commonly found when the body is infected, a pattern that dendritic cells are trained to recognize as a sign of trouble. The dendritic cell that encounters the antigen+adjuvant, isn't just intrigued, it is alarmed! As a consequence, it immediately migrates from the skin, through the lymphatic vessels to the lymph node.
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| Figure 1: A Dendritic Cell encounters Antigen |
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| Figure 2: Our Dendritic Cell meets with B cells in the lymph node |
When the dendritic cell and the B cell that recognizes the antigen meet, they form a stable interaction and dance around for a while. I don't just make this up, it really happens! Below, I've posted a cool movie that demonstrates this interaction in the lymph node of a living mouse. The dendritic cells are green, the T cells (in this case) are red. Notice how the dendritic cell meets with many uninterested cells until it finally forms a stable interaction with one cell.
However, your immune system doesn't stay on red alert after each antigen you encounter! Otherwise you'd be constantly sick and feverish. Instead, when the infection is cleared and no dendritic cells come in anymore carrying fresh antigen, the immune system goes to sleep again. However, so-called 'memory cells' remain. They carry the memory of the infection they encountered, the memory too, of the vaccination. It is because of these memory cells that your immune system reacts much faster and much more effective to a second encounter with the same antigen. They awake and raise the alarm in hours, instead of days, when another dendritic cell comes in with despised antigen they knew before!
Memory cells can live a long time, but not forever. About 60 years is the life-span of a memory cell. That's why elderly people are again susceptible to diseases they had immunity against before. We don't really know why some infections and some vaccines give good immunological memory and others do not. Life vaccines generally work best and longest, but why? Research on that topic is, of course, ongoing. It is also good to realize that some vaccines wear off after 10 years or so. The pertussis (whooping cough; the 'P' in the DTP vaccine) vaccine, for example. Whooping cough is not lethal for adults, only really for infants, so it doesn't really matter for you. However, you can't transmit immunity that you don't have to your infants by breast feeding .
How does that work? Your immune system always makes some antibodies against everything you're immunized for. When you're pregnant, those antibodies are shared with the fetus in your womb through a very ingenious mechanism that filters out all antibodies that might otherwise kill your fetus (after all, the fetus is only half 'you' and half its dad). Your baby is therefore born with some immunity. Immediately after birth, babies' own immune system starts developing and reacting to everything it encounters. Mother's milk also contain antibodies and some immune cells that further protect your baby, but only temporarily (and only from whatever you're still immune for). Vaccination (and only vaccination!) at about 2 months will help your baby build lasting immunity against all those diseases you don't want your child to get.
Fruits, a healthy diet and life style, homeopathic medicine and prayers won't protect your child, since none of these things challenge the immune system with antigen. None of these things can help you build immunological memory for lasting protection. A healthy life style can fortify your immune system to some extent, but even a fortified immune system can only respond rapidly to what it encountered before. It would still need about a week to respond to something new and a week is plenty of time to die from a tetanus infection, for example, or for measles, HPV and many other viruses to make themselves at home in your body and dodge your immune system altogether.
To some extent, vaccination is your decision. You want to brave the Amazonian jungle and die of yellow fever? Fine, go ahead, be my guest. But you think about going back home with the virus and make us all sick! If you don't vaccinate your child against whooping cough, measles, polio or HPV, it isn't just you who runs the risk, it's others too! Newborns hardly have any protection at all against whooping cough, for example, and will die if they catch the disease. Is that what you want?
















