- Nearly 40 years after Lady Montagu brought variolation
to Britain, an eight-year-old boy
is variolated in Gloucestershire.
He will grow up to be a doctor who will change the world.
His name is Edward Jenner.
This is Edward Jenner's study.
And it was right here
that he wrote this book about his scientific work.
And in it, he tells us that in May, 1796
he met a milkmaid named Sarah Nelms,
and she had contracted cowpox,
and a huge sore, a pustule had developed on her hand.
Now Jenner is so interested in this
that he includes this drawing in book showing
the sore on Sarah's hand.
(cow moos)
Milkmaids catch cowpox, a mild skin disease,
from the udders of infected cows,
but they rarely catch smallpox.
And they're famous for having unblemished faces.
This sets Jenner thinking.
Perhaps catching cowpox prevents milkmaids
from catching smallpox.
And that led him to develop a theory
that it might be possible if you infected somebody
with cowpox to protect them from smallpox.
If it works, it will be far safer than variolation,
which exposes people to a deadly disease.
Jenner tests his theory.
The piece of medical equipment
that Jenner uses is; it's a lancet, a sharp blade,
and this one was actually owned by Edward Jenner.
And what he did was he cut into the pustules on the hand
of Sarah Nelms and he extracted some of the fluid inside.
(dramatic music)
The next thing he needs to do is to find someone to
be the subject of this experiment.
And he chooses somebody close at hand, James Phipps,
the eight year old son of his gardener.
Jenner took the lancet and he made two small incisions
into the boy's arm,
(dramatic music)
and smears some cowpox fluid into the cuts.
(dramatic music)
Over the next days, Jenner observed the boy's arm
as the mild cow pox infection develops.
(dramatic music)
Six weeks later, Jenner moved on to the next
and far more dangerous stage in his experiment.
He cuts James again.
This time he smears smallpox into the wounds.
Amazingly, he develops no symptoms of the disease.
Jenner's new vaccination method
is safer than variolation.
Exposure to a mild disease, cowpox, brings protection
against the biggest killer of the age, smallpox.
(dramatic music)
- The Jenner story is a classic.
I mean, it's one of the few stories
of scientific breakthrough that you will actually read
in a traditional history survey of the modern age,
but there's something kind of misleading about it in a way.
Yes, the vaccine is an important breakthrough
but it was clearly building on
this longer history of variolation.
He was modifying and refining an existing idea
that had a much, much longer history.
- Smallpox is always there.
It's always on humanity's shoulder
and it's not surprising that this global disease,
this technology to address it, was one that spread
around the world on exactly the same currents
as the disease trade empire migration movement.
- The thing that's fascinating about Jenner's work here for
for all of his brilliance, he fundamentally
doesn't understand how the immune system works, right?
No one does at that point in our history,
but today we actually do understand all of that.
We have a much richer comprehension
of the body's immune system
and that is enabling us to design a whole new class
of vaccines that would have exceeded anything
in Jenner's imagination.