How Do Vaccines Prevent Diseases?

Our bodies can often prevent us from catching the same illness twice, and vaccines use that bodily system to prevent us from getting sick in the first place. Learn how the immune response works, what goes into vaccines, and why vaccines are safe for kids in this episode of BrainStuff, based on this article: https://health.howstuffworks.com/wellness/preventive-care/vaccine.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brainstud a production of iHeartRadio, Hey Brainstuff Lauren
vogelbaumb Here. We may not have flying cars or hoverboards yet,
but in some ways we truly live in the incredible future.
For a trip or two to a healthcare professional and
a nominal amount of money, if any out of pocket,

(00:24):
we can prevent ourselves from getting sick. Vaccines are considered
the most successful medical advancement in the history of public health.
Before vaccinations, diseases like smallpox, polio, and rebella killed or
paralyzed or caused serious birth defects regularly. These losses of
life and types of suffering are now preventable with extremely

(00:48):
small risk. A person born in the United States in
the year nineteen hundred had an average life expectancy of
forty seven years. As of twenty ten, it was seventy
eight years. That's not because most adults never reached old
age in the past. It's because babies and toddlers died
way more often of diseases that we now vaccinate against.

(01:11):
So today, let's talk about vaccines and the basic science
behind how they prevent illness. We'll also go head to
head with some of the common myths about vaccines. A
Vaccines work based on the fact that once a person
has caught a disease of some types, they'll probably be
immune to that disease for the rest of their life.

(01:32):
For example, once you've had chicken pox, it's extremely unlikely
that you'll ever catch it again. This is because your
body will recognize the disease and fight it off. This
happens thanks to a process called the immune response. The
beauty of vaccines is that they help your body develop
these disease recognizing abilities without you needing to get sick

(01:54):
in the first place. Here's how the immune response works.
When a virus or or bacteria enters your body under
normal circumstances, your immune system will identify it as a
potential threat, recognizable because it has molecules on its surface
called antigens. If your immune system identifies those antigens as

(02:15):
being not from your own body and therefore potentially unsafe,
it'll launch an attack. Your immune system attacks by developing
invader specific proteins called antibodies that can destroy the antigen
than anything attached to it, or tag it for destruction
by immune system cells. After the battle, your immune system

(02:35):
will stockpile that antibody and remember how to identify that
antigen in most cases forever, so if your immune system
encounters antigens of the same type later on, it can
fight the disease off fast. Unfortunately, antibodies are really specific,
so if you've had chicken pox, for example, that's great

(02:56):
for preventing chicken pox, but useless against other diseases. When
a disease infects a person, the germs that cause it
multiply thousands and thousands of times until a raging infection
is underway, which can have all kinds of unpleasant or
even deadly effects. A vaccine provides just enough antigens for

(03:16):
the body to recognize them and complete the immune response
process without causing an infection. Vaccines are able to provide
that goldilock zone of just enough antigens in two basic ways,
through weakened germs or through inactivated germs. Vaccines that use
weakened germs are also called live attenuated vaccines. Attenuated means weakened.

(03:42):
When this type of vaccine is created, the virus or
bacteria is weakened in a lab to the point where
it's still kicking and able to reproduce, but it can't
cause serious illness. It might reproduce a couple dozen times
instead of thousands, but its presence is enough to cause
and complete the body's immune response. Live attenuated vaccines can

(04:05):
cause mild illness in some people, a low grade fever,
a runny nose, or a few chicken pox spots, but
it's maybe a day or two of discomfort, nothing compared
to the full blown illness. To weaken the virus or bacteria,
researchers take a specimen from an infected person. They then
grow the germ in a test tube, a tissue culture,

(04:27):
a chicken egg, or some other foreign host. They pass
the germ into a second test tube or whatever, then
a third, a fourth, and on and on. The measles
virus was passed seventy seven times. Eventually, the germ gets
so used to living in that comfortable test tube or
other host environment that it loses its capacity to produce

(04:49):
illness in living humans, but will still bear its identifying antigens.
Examples of live attenuated vaccines are those for MMR, that is,
the diesels mumps and rubella combo vaccine, chicken pox, and
the entran nasal form of the flu vaccine. The other
type of vaccines uses inactivated germs. In these, the virus

(05:13):
or bacteria has been rendered completely ineffective or dead, although
one could argue that viruses aren't really alive to begin with.
Researchers accomplish this with compounds like formaldehyde or detergents, which
are then separated out from the inactivated germs. Pieces of
the germs, including their antigens, go into the vaccine, which

(05:35):
can thus trigger the immune response with zero chance of
an actual infection. Unfortunately, the strength of these vaccines tends
to wear off over time, resulting in less long lasting immunity,
so multiple doses of inactivated vaccines are usually necessary to
provide the best protection. Examples of inactivated vaccines are those

(05:56):
for heptitis A and B, polio, meningitis strip and and
the injected form of the flu vaccine. Inactivated vaccines are
preferable because they're safer, and most bacterial vaccines are this type,
but viruses often require live, attenuated vaccines because that's the
best we can do to fight them. There are some exceptions.

(06:18):
For example, rabies is a virus that's too dangerous to
give people in a week ined state because a Rabi's
infection is always fatal in humans, so doctors don't want
to take any risks. I'll have to do a whole
other episode on how vaccines are developed because it's a
big topic. But let's talk about what all goes into
a vaccine other than the germ and or its antigen,

(06:41):
which could be considered the active ingredient. Every vaccine is
unique to the disease in question, but here's the gist. First,
many vaccines contain what's called adjuvants, which are helpful substances
that make the vaccine more effective. Very basically, adjuvants a
felly poke at your immune system to make it react

(07:02):
more strongly to the mild threat that the vaccine poses. Next,
you've often got a stabilizer, which is a substance that
helps protect the active ingredient as it's stored and transported
in different temperatures and levels of jostle. Finally, when vials
of a vaccine contain multiple doses, a preservative or disinfectant

(07:24):
is required. This is so that every time a dose
is removed by needle, any microbe that, against all odds,
comes into the vial with that clean needle is killed
in the vial and thus won't be able to cause
an infection in the person receiving the next dose of
the vaccine. All of these substances are thoroughly regulated to

(07:45):
ensure their safety in the amounts in which they're used.
Health experts recommend so many vaccines for babies and young
children because they're more risk for serious infections. It's a
little bit gruesome, but really important to under stand that
the diseases that infants and children are vaccinated against today
are truly horrifying. For example, diphtheria, a nose and throat

(08:09):
infection that can cause difficulty breathing, heart failure, and paralysis
once killed over fifteen thousand children a year in the
US alone. Or take meningitis, an infection of the covering
around the brain and the spinal cord. Survivors can face
brain damage, deafness, and seizures. Polio once infected up to

(08:30):
twenty thousand Americans a year, and survivors are often left
paralyzed and dependent on mobility tools for the rest of
their lives. Measles doesn't just cause a rash, it can
cause brain swelling and even death. Mumps can cause deafness
and brain damage, and rebella, which is often transmitted to
unborn fetuses during pregnancy, can cause miscarriages or premature births,

(08:54):
and birth defects in survivors. All of this is why
researchers have spent so much time, time, and effort and
money developing safe vaccines. Still, there's a lot of vaccine
uncertainty out there right now, and a lot of concerns circulating,
which is fair and healthy. Asking questions is good. So

(09:17):
let's address a few of the common ones first. And
the elephant in the room is the concern that vaccines
might cause autism. This is, in essence, a lie that
was manufactured starting the nineteen nineties by this guy named
Andrew Wakefield, who was at that time a doctor. His
license has since been revoked. He got a study published

(09:40):
in the renowned medical journal The Landset in nineteen ninety
eight that supposedly linked the MMR vaccine to autism in children,
but when other doctors and researchers started looking at it,
they realized that Wakefield study didn't prove that at all.
He had cherry picked his cases and didn't show any
real evidence. The Landset retracted the study and apologized for

(10:02):
printing it in twenty ten, but due to publicity. The
idea of the link still spread. The story even morphed
from the supposed culprit being the MMR vaccine to thimerasol,
which is a preservative that contains mercury. Lots and lots
of further studies have been done that have shown no

(10:22):
link between any vaccines and autism. Also, it later came
out that Wakefield was poised to make tens of millions
of dollars a year on this diagnostic test that he
had patented based on his falsified link. The whole thing
has been called one of the most serious frauds in
medical history because it has made people feel less safe

(10:45):
about saving their children from these terrible diseases. If it helps.
Amid all of this concern, vaccine makers have stopped using
thimerasol in just about all vaccines, just to reassure people
that they're safe. Next step, let's talk about the concern
that vaccines are unnecessary because those diseases are pretty much

(11:06):
gone anyway. Unfortunately, the only vaccine preventable disease that's been
completely wiped out is smallpox. Other diseases can still spread
through things like international travel that take measles. For example,
It was considered gone from the US as of the
year two thousand, but as of September ninth, of twenty
twenty five, there have been one thy four hundred and

(11:28):
fifty four cases confirmed here this year, resulting in one
hundred and eighty hospitalizations and three deaths. Any deaths from
a preventable disease are too many. Another fair concern is
that babies are too fragile that their immune system is
going to get overwhelmed by receiving so many vaccinations at once.

(11:50):
But babies get an immune workout all the time on
play dates, at church, at the grocery store. Vaccines can't
overwhelm a functional immune system, and you would know there
would be signs or your health care provider would tell
you if your kid was an exception. There are people
who can't receive vaccines because of a weakened immune system,

(12:11):
like some patients with cancer. That is part of why
public health experts want healthy adolescents and adults to stay
up to date on their immunizations too. Vaccines prevent healthy
people from getting sick, which means, well, first off, we
won't suffer the annoying to painful effects of illness, and
we won't fall behind at home or at work. And

(12:34):
second of all, if we don't get sick, we won't
pass on an illness to someone more at risk for
severe symptoms, including death. Getting vaccinated can save a life.
It might be yours, it might be a loved ones.
Insurance often covers them, and walking clinics often provide them
for cheap Again, it's normal and good to have questions

(12:57):
or concerns, and please talk to a healthcare provider if
you do. After all, at the end of the day,
I'm just a podcast host. Today's episode is based on
the article how vaccines Work on HowStuffWorks dot com, written
by Leah Hoy. Brain Stuff is production by Heart Radio

(13:17):
in partnership with HowStuffWorks dot Com and is produced by
Tyler Klang. For more podcasts from my heart Radio, visit
the iHeartRadio app, Apple Podcasts, or wherever you listen to
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