>> Hi, my name is Paul Offit.
I'm talking to you today from the Vaccine
Education Center at the Children's Hospital
of Philadelphia.
One question that parents reasonably ask is,
"Is it possible that vaccines could cause
autoimmune diseases or chronic diseases?"
And by autoimmune disease I mean a disease
where the body reacts against itself.
Now, it's certainly true that certain viruses
or bacteria can cause autoimmune diseases.
So, for example, Lyme disease
is caused a bacteria.
When you're infected with that bacteria, you
generally rid yourself of it, but it can cause
chronic, or long-term, arthritis, meaning
inflammation of the joints.
Because when the body reacts to the bacteria,
it's also reacting against itself;
essentially reacting against its joints.
Similarly, strep throat can set
up for rheumatic fever.
So, while you're reacting to the bacteria
that causes strep throat, you're also reacting
to the lining of your own heart that can cause
symptoms and signs of rheumatic fever.
So, we know that bacteria can do it.
We know that viruses can do it.
The question is, can vaccines do it?
Now, there are few examples that I think
help to answer that question.
One is that there was a Lyme vaccine; it was
used in the United States between 1998 and 2002.
And while it was clear that Lyme bacteria
could cause chronic, or long-term, arthritis,
the Lyme vaccine couldn't do it because it
didn't have what it took to drive the immune
response to cause autoimmunity.
Similarly, if you look at people who have
multiple sclerosis, when they're infected
with natural, or so-called wild type, influenza
virus, they have a worsening of their multiple
sclerosis -- that's clear.
However, when they're given the vaccine,
they don't have that.
So, again, in many ways then, the influenza
vaccine prevents the exacerbation, or worsening,
of multiple sclerosis in someone
who has multiple sclerosis.
Now, there are a couple of very rare examples
where a vaccine could cause autoimmunity,
or said another way, the vaccine could cause
the body to react against itself.
One is influenza virus.
It is possible that roughly 1 per million
people who get an influenza vaccine can have
a disease called Guillain-Barré syndrome,
where the body essentially reacts against
itself and causes this sort of ascending paralysis;
it starts at the legs and then works its way
up the body and can affect breathing.
Now of interest, influenza virus, the natural
virus, also causes Guillain-Barré syndrome
at a rate roughly 17 times greater than that
that's caused by the vaccine, or said another
way then, the influenza vaccine then, arguably,
prevents Guillain-Barré syndrome.
There's one other isolated example where a
vaccine could cause autoimmune disease.
It occurred in Europe; it occurred in 2009;
it was associated with a squalene-adjuvanted
influenza vaccine, called Pandemrix®.
Now, the rate of narcolepsy, which is a permanent
disease of wakefulness, that was caused by
that vaccine was, depending on the country
you looked at, between 1 in 15,000 to 1 in 50,000.
We never used that vaccine in this country,
the United States; it was never used again,
and so I don't think that's ever gonna
be a problem again.
So, I think that we can feel comfortable that
for all the diseases that are associated with
autoimmunity, and frankly for all the diseases
that are just sort of chronic diseases that
are not associated with autoimmunity, there
have been study after study after study showing
that vaccines don't do that.
And vaccines really, frankly, are the safest
best tested things we put in our bodies because
ounce they're licensed, regulatory agencies
and academic institutions look very hard to
see whether it's at all possible that vaccines
are doing more harm than good, that vaccines
might be causing autoimmune or chronic diseases,
and clearly and consistently that's been shown
not to be true with the exception of the couple
rare instances I mentioned.
So, again, vaccines are safe and effective,
and a choice not to get them is not a risk-free
choice, it's just a choice to take a different
and more serious risk.
Thank you.
