What ingredients are in vaccines? | The Vaccines Project, Episode 2


-Aluminum, formaldehyde,
dead viruses — Why would we put any of those
things in our children’s bodies? This is a legitimate question that many parents
ask about vaccines. So, what’s actually in them,
how are they made, and are the ingredients harmful? In the last episode, we learned
how the smallpox vaccine was made over 200 years ago. It was super effective and ended up eradicating
smallpox all over the globe. But the way it was produced, by taking pus
from one person or animal and giving it to another, was really crude compared to
the vaccines that came after it. I mean, ew. But the technology
got way more advanced. Take diphtheria. It’s a disease most people
in developed nations have never seen because of successful
vaccination programs. But through the 1800s,
it terrified American families. Diane Wendt from the
Smithsonian’s National Museum of American History
told me about it. -diphtheria’s an infectious
disease that’s caused by a bacteria. It was called “the scourge
of childhood” or even
“the grim scourge of childhood,” and “the strangling angel” was
another name for the disease. And part of what was really
scary about the disease is that the bacteria that gathers
and starts in the throat and everything produces a toxin. So, it’s poisoning the body, but it also kind of
kills off cells, and it produces this membrane, which they called
a pseudomembrane, which can actually close off
the throat and, basically,
asphyxiate a young child. diphtheria could be lethal,
and there was no way to cure it, though doctors had some
fairly gruesome ways to help children breathe. One was to perform a tracheotomy by making a hole
in their throat. Another was to insert
a breathing tube through the pseudomembrane. -You can see 1, 2,
and then we get 6, 7, 8, 9, and 10 to 12. And that’s actually the ages
of the kids that it was intended for. -That’s so heartbreaking. But things changed dramatically
in the 1890s with a new type of treatment. -Unlike smallpox, which the
treatment and the vaccine for smallpox
kind of arose out of an empirical
almost folk medicine, if you will,
this was a treatment that really came out
of what was scientific medicine in the new science
of bacteriology. -The treatment was called
“antitoxin,” and, essentially, it was
a preparation of antibodies that neutralized
the diphtheria toxin. It was made by injecting horses
with the toxin, waiting for them to build
an immune response, harvesting antibodies
from their blood, and giving those antibodies
to diphtheria patients. Now, I don’t want to minimize
the effect the bleeding had on the horses,
but know that horses are less affected by diphtheria
toxin than humans are, so they only developed
a low-grade fever. -The new treatment came out of
the bacteriology lab in Germany, and it was kind of announced
to most of the world in 1894, and there was so much demand
for it and so much excitement over it,
that, in the United States, the public health departments
immediately put things into force to try and start to make
this new treatment. -Now, antitoxin was a treatment,
but not a vaccine. It didn’t confer
long-term immunity because the patient’s own body wasn’t learning
how to make antibodies, but, eventually,
scientists figured out how to create an inactivated
form of the toxin called a “toxoid.” Toxoids could evoke an immune
response in a healthy person without making them sick,
so if the person ever encountered diphtheria
in the future, their immune system would know
which antibodies to produce. This is how most vaccines
today are made. We use toxoids or weak
or dead version of germs to bring on
an immune response. For example, diphtheria
and tetanus vaccines still use toxoids. The measles vaccine uses
a highly weakened form of the measles virus, and the polio vaccine
uses a dead virus. Now, here’s the thing. Toxoids are so harmless
that your body sometimes doesn’t bother
mounting an immune response. This was initially the case
with the diphtheria toxoid. It just didn’t make
the immune system angry enough. But back in the days
of the antitoxin treatment, scientists found that
when horses had a little inflammation
at their injection sites, they actually produced
more antitoxin. It was like the inflammation
hailed more immune cells to come check out
what’s going on. -They found that if you could
add some substances to these toxoids, you could kind of do
the same thing. You’d get a better immune
reaction from the body, and those are called
“adjuvants,” and they’re actually really
critical to vaccines today. -The adjuvant used in that
first diphtheria vaccine was the form of aluminum, which is still
in certain vaccines today. It’s not in the measles vaccine,
but it is in DTaP, which is one for diphtheria,
tetanus, and pertussis. The amount of aluminum, however,
is really small, and aluminum is in a lot
of other products we consume, including antacids
and some baby formulas. Additives are one of
the most controversial topics surrounding vaccines today,
so, while we’re on the subject, let’s talk about
two other adjectives that people get nervous about,
formaldehyde and thimerosal. Formaldehyde is used to
deactivate certain germs and also toxins,
turning them into toxoids. The vast majority of
the formaldehyde is removed before the vaccine
is administered, but a very small amount
does make it into the final mixture — less than the amount found
in a single pear. Thimerosal is a mercury-based
preservative that’s sometimes
used to keep bacteria from growing in the vaccine. It’s actually in very few
vaccines today. Some flu vaccines that
do contain it have about 25 micrograms
of mercury per dose. That’s the same amount
of mercury in a 3-ounce can of tuna. But on top of that, the type
of mercury found in thimerosal is different than the type that
can make fish dangerous to eat. It gets broken down
by our bodies far more quickly. But if you’re still concerned,
you can get a version of the flu vaccine that doesn’t
contain thimerosal at all. There’s a common misconception
that thimerosal was at one point in the MMR or measles, mumps,
and rubella vaccine. It actually never was. In 2001, however,
due to public fear that thimerosal was somehow
linked to autism, it was removed
from all childhood vaccines, simply to reassure parents
that vaccines were safe. There was no scientific evidence
at the time that linked thimerosal
to autism, and since it was removed
from those vaccines, scientists have seen no decrease
in autism rates. In the late 1800s, with advances in vaccine
creation and microbiology, it seemed possible
to fight any illness. Louis Pasteur famously claimed, that it was
“within the power of man to eradicate infection
from the Earth.” But, of course,
that didn’t happen. We’ve made vaccines
for many horrible illnesses, but there are still more
we haven’t been able to crack. However, new technology
might be changing that. To learn about it, I went to
the Vaccine Research Center at the National Institutes
of Health. -Classic vaccines have been
incredibly successful, but we’ve made the ones
that are on the easy side. The ones we don’t have
are the hard ones. -Take flu and HIV. They both evolve really quickly, changing the antigens
that coat them. That’s why we typically need to
get a new flu shot every year. -The influenza virus, it’s almost like
it’s dressed up. It’s wearing party clothes,
and each year, it sort of changes its outfit. -That’s exactly right,
and, so, scientifically, we say, “Okay, how does the virus work?” It has to get into the cell. What part of it does it use
to get into the cell? It can’t change that. But if we can be really smart,
we can extract that part, show the immune system
that part of the virus that usually is hidden,
and we can make a response that’s more acceptable
across all different types, no matter how the virus changes
its dress code. -New techniques are also making
it possible to create a vaccine without even needing a weak
or dead version of the germ. Take zika, for example. -So, that was a virus
that we knew about, but was pretty rare and only had
occurred in a few places, and all of a sudden, it took off
and started to spread through large populations
and cause disease. So, people went out
in the field, and they isolated just samples
from people who were affected, sequenced the virus, and, actually, that sequence
was sent to us digitally. We never actually see the sample
of the virus. -The scientists could then
take the gene that codes for a particular zika protein
and use that to make a vaccine. If you inject only that gene
into human muscle, the muscle cells
temporarily read the DNA just like
their own genetic code. For a short time, they act like
little factories producing
the harmless zika protein. That allows the body to build up
an immune response to zika without a person ever coming into contact
with the virus itself. Another new technique
to make vaccines that don’t include germs
is nanoparticle technology where scientists can create
a small particle in the lab that looks like
a particular virus. -That’s particularly useful
for dangerous viruses. If you think about ebola,
for example. We don’t want to be dealing with growing a fatal virus
in a laboratory or even using a classic approach
like trying to kill that and injecting a killed
ebola virus back into people, so we can use a virus-like
particle or a nanoparticle that looks like ebola virus. -New technology like this
could soon help us prevent more diseases
than ever before, but when you make a new vaccine,
how do you know it’s safe, and is anyone checking to see if there could be
any long-term effects? In the next episode, we’ll learn how vaccines
are tested for safety and why there’s been so much
controversy over vaccines and autism.

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