But, a growing group of people

seem to believe that they endanger our health, instead of protecting it.

The Internet is full of stories about allergic reactions,

the onset of disabilities,

and even death following vaccination appointments.

And, it's true vaccines can have side effects.

Let's look at how they work, and how dangerous they really are.

Your immune system is a complex army of billions of cells.

Soldiers,

intelligence cells,

and weapons factories.

Every day, you're attacked countless times,

but your immune soldiers alone usually deal with that,

so you don't even notice.

If an infection becomes serious though,

our intelligence cells gather intel about the attackers

and activate our weapons factories.

You know the weapon: antibodies.

They're like targeted missiles produced specifically to combat the invader.

Unfortunately, this process takes several days to complete.

That gives intruders a lot of time to do damage.

Contrary to popular wisdom,

what doesn't kill you doesn't make you stronger.

Our bodies really don't want to fight serious wars over and over,

so our immune system came up with an ingenious way

to get stronger and stronger over time.

If we fight an enemy that is dangerous enough to trigger our heavy weapons,

our immune system automatically creates memory cells.

Memory cells remain in our body for years, in a deep sleep.

They do nothing but remember.

When an enemy attacks for a second time,

the slumbering memory cells awaken,

and order coordinated attacks and the production of antibodies.

This is so fast and effective,

that many infections you beat once will never make you sick again.

You might even be immune against them forever.

Which is also why little kids are constantly ill;

they don't have enough memory cells yet.

And this beautiful natural mechanism is what we build on when we use vaccines.

How Vaccines Work

As great as memory cells are,

obtaining them through an infection is unpleasant and sometimes dangerous.

Vaccines are a way of tricking our bodies into making memory cells,

and becoming immune to a disease.

They pretend to be a dangerous infection.

One way of doing this is to inject invaders that can't do harm.

For example, by killing them, or by ripping them into pieces.

Our immune systems deal with these kinds of vaccines pretty easily.

Sometimes, it's necessary to make our immune system work harder though,

to produce even more memory cells.

Live vaccines are the real deal.

An enemy that can punch back is a bigger challenge than a dead one.

But this also sounds like a sort-of horrible idea.

What if the germs win?

To avoid that, we breed a sort-of weak cousin of the real germ in the lab.

Just powerful enough to annoy the immune system, and create enough memory cells.

Okay, so these are the basic principles of vaccine use.

They provoke a natural reaction in our bodies

that makes us become immune against very dangerous diseases.

Some, like the flu virus, mutate so often

that we need a new vaccine every year,

but most vaccines protect us for years, or even a lifetime.

But, there's a catch.

Like everything in life, vaccines have another side:

Side effects.

What are they, and what happens if your child develops one?

The Risks of Vaccines

It's complicated to directly compare the side effects of vaccines with the effects of diseases.

For example,

hundreds of millions of people are vaccinated against measles in the West,

but there were only 83,000 cases in Europe in 2018.

So, with numbers that different, even mild side effects can seem scary

compared to the bad effects of a disease that we don't see as much anymore.

Before the measles vaccine became available in 1963,

virtually every single child on Earth contracted measles at some point.

An estimated 135 million cases in the 1950s.

Every single year.

But are measles really that dangerous in the year 2019?

With our advanced healthcare and new technologies,

are they worth the risk of vaccine side effects?

Let's do a thought experiment based on real numbers.

Imagine a developed country in a parallel world.

It has good healthcare but people stop vaccinating.

In this scenario, let's say ten million children caught measles.

What happens?

Nine million eight hundred thousand, or 98%, will get a high fever and a very unpleasant rash.

Up to 800,000 of them, or 8%, will suffer from dangerous diarrhea.

700,000, or 7%, will suffer from an ear infection, which can lead to permanent hearing loss.

600,000 kids, or 6%, will suffer from pneumonia -- the most dangerous effect of measles.

It, alone, will kill 12,000 children.

Up to 10,000 children, or 0.1%, will get encephalitis.

2,500 kids, or 0.025%, will contract SSPE,

a disease where the measles virus lingers in their brain

and kills them a few years later.

Taken together,

around 2.5 million children will suffer from somewhat serious effects from measles.

And, about 20,000 children will be killed by measles.

It doesn't stop here though.

The kids who beat measles are left with a severely damaged immune system

that needs a lot of time to regenerate.

Time for other diseases to do further damage.

Aside from that, what's almost guaranteed

is that your kids will have a really bad time for about two weeks.

Okay, but what about vaccines?

It's only fair to look at these risks, too.

So, let's repeat our thought experiment.

But, this time, we vaccinate ten million children with MMR.

What would theoretically happen here?

After being vaccinated,

of our 10 million kids, around ten percent get a fever.

500,000, or 5%, will get a mild rash.

Up to 100, or 0.001%,

might have a serious allergic reaction and will have to be treated.

Up to ten boys, or 0.0001%,

might get inflammation of the genitalia.

And up to ten kids in total, or 0.0001%,

might get the most serious side effect: encephalitis.

So, we vaccinated ten million kids.

In total, around one hundred and twenty had side effects that were somewhat serious.

Thanks to good medical treatment in developed regions, almost all of them will be fine.

What about autism?

The connection of autism and vaccines stems from one source

that has been disproven countless times.

We'll link to further reading and videos in the description.

But, in 2019, it's fair to say that vaccines do not cause autism.

All right, but what about deaths?

It's really hard to say if even a single one of our 10 million vaccinated kids would die.

We really did look hard and talked to a lot of different experts.

If we ignore self-reporting,

we could only come up with a tiny handful of documented cases

for all the hundreds of millions of children who received the MMR vaccine since 1971.

Measles are many, many thousands of times more dangerous for your child

than even the absolute worst case of vaccine side effects.

You have to search for lethal vaccine side effects with a huge magnifying glass

and, even then, it's very hard to find confirmed cases.

While, deaths from measles are real and easy to find.

In 2017 alone, 110,000 people died from measles worldwide.

Statistically, today, 300 children will die of measles.

One since this video started.

You can compare vaccines to seatbelts.

Are there weird freak accidents where someone gets killed by their seatbelt?

Well, yes.

But, do you personally think it's safer to not put a seatbelt on your kid?

Wait a second!

What if your kid is actually allergic?

What if none of the things we've said applies to your specific situation?

In this case, you need to become the greatest vaccination promoter of all.

Because if your children can't be vaccinated, only the collective can protect them.

This is called herd immunity,

and it's the only thing that can protect your unvaccinated child.

Herd immunity means that enough people are immune to a disease,

that it can't spread, and dies before it reaches its victims.

But to accomplish this for measles alone,

95% of the people around you need to be vaccinated.

Conclusion

The problem with the debate about vaccines is that it's not fought on a level playing field.

While the pro-vaccine side argues with studies and statistics,

the arguments against them are usually a wild mixture of gut feeling,

anecdotes, and misinformation.

And feelings are often immune to facts.

We'll not convince anybody by screaming at them.

But we can't hide from the reality of what anti-vaccine conspiracies do.

They kill babies too young to be vaccinated.

They kill healthy children that are just unlucky.

They bring serious diseases back from the verge of extinction.

And, the biggest side effect of vaccines is fewer dead children.

Vaccines are one of the most powerful tools we have

to eradicate the monsters that most of us have already forgotten.