One of the major challenges scientists face is communicating important
information to the general public. As brilliant as many of them are, hours
spent in a lab hunched over a microscope do little to improve a person’s
ability to explain things simply and comprehensibly. Complicating things
further is the fact that scientists are trained to constantly question and test
their ideas so they say a lot of things like “we believe” and “these results
suggest” when really they mean “I am sure this is true, these are facts.” When
you’re talking about the evolutionary history of Amazonian frogs or something
like that, it tends not to matter; but occasionally a topic comes along where a
clear explanation of how things work is even more important than a detailed
reporting of the facts. Vaccines are one of those topics.
Right now in the Fraser Valley of British Columbia Canada, several
hundred people (mostly children) are infected with an unpleasant and
occasionally fatal illness that scientists basically cured a long time ago.
Over 200 cased of highly contagious measles have popped up in the region and a
few infected people have found their way to Ontario and the Atlantic coast, largely because the Fraser Valley has one of the lowest measles
vaccination rates of anywhere in Canada (between 70 and 80%).
Much of the problem lies in the fact that vaccines inject viruses and
bacteria into people’s bodies. Generally speaking we are taught that this is a
bad thing, so our instinctive reaction is to avoid it. Teaching people that
infections are bad and then telling them that you need to inject them with a
virus is generally a hard idea to sell because, quite frankly, it makes you
seem insane.
The truth is vaccines actually are made of the viruses and bacteria that
they are trying to prevent. To understand why that is necessary we need to
understand the immune system. You see, when an unfamiliar virus or bacteria
makes its way into your body it sounds an alarm that activates an immune system
response. These invading organisms are called antigens and their goal is to
replicate as much as possible.
Since our bodies are not designed to handle that
sort of thing the results can be very bad, resulting in sickness and sometimes
even death.
Your body doesn’t like dying, so once that alarm is sounded you’re white
blood cells get to work. Your T-cells identify which cells in your body are
infected by the intruder and destroy then to try to contain the infection.
Meanwhile your B-cells produce antibodies, which attack antigens directly and
try to prevent them from infecting more of your body’s cells.
Vaccines take advantage of this response by tricking your body into
thinking it has been infected by a specific virus or bacteria, but in order to
do that they need to introduce some of these intruders into your body. Obviously
the goal of vaccines is to prevent infection so it wouldn’t make much sense to
pump you full of measles. Instead, vaccines use a weakened or inactive (dead)
form of the intruder/antigen.
Vaccines that use weakened antigens are called live-attenuated vaccines,
because they inject still living infections. The trick with live-attenuated
vaccines, however, is that they use the dumbest, laziest individual viruses and
bacteria possible. To create these vaccines scientists take something dangerous
like measles and give it a relaxed, cushy life in a test-tube. The infection is
continually transferred from one test tube to another, each time getting a
little more used to the good life. After enough time and transfers (77 in the
case of the measles virus) the infection is so used to not have to do anything
to survive that it has lost most of it’s tenacity. When injected into the
bloodstream these infections reproduce at most 20 times rather than the
thousands and thousands of times they normally would. Your body is easily able
to identify and destroy these antigens.
The cool thing is that you immune system has a great memory, so once the
infection is gone your B-cells continue to produce the antibodies that can kill
it, making you immune for life.
Inactivated vaccines use dead viruses that don’t reproduce at all. The
benefit to this is that there is zero chance of any kind of negative reaction
(live-attenuated vaccines can lead to soreness at the injection site and
occasionally some mild symptoms), the downside is that you often need multiple
shots to maintain immunity because your body thinks the disease is a dud.
One of the most publicized fears about vaccines is so-called link
between vaccination and autism. This link is a myth. It arose when some people
discovered that a disinfectant used in some vaccines (Thimerosol) contained
mercury. There is however no reliable research supporting this claim (Parker et
al., 2004). Even still, most vaccines now contain no Thimerosol because the
companies that produce the treatments want to make parents feel as safe as
possible. One real health concern that goes along this vaccines is the risk
that some flu shots pose to people with egg allergies. Since influenza is grownin eggs to create the vaccine, there is a chance it can cause an allergic
reaction. If you’re allergic to eggs to can still get a flu shot, you just have
to talk to your doctor about getting one of the varieties that is not developed
using eggs (there are plenty).
3 comments:
I just found your blog today and totally loved it!!!
Glad you're enjoying it!
zzzzz2018.5.7
ralph lauren outlet
dsquared2
nike factory outlet
ralph lauren outlet
nike trainers
coach outlet online
canada goose jackets
nike roshe
kate spade outlet
broncos jerseys
Post a Comment