1
00:00:07,093 --> 00:00:08,630
10,000 years ago,

2
00:00:08,630 --> 00:00:12,018
a deadly virus arose in northeastern Africa.

3
00:00:12,018 --> 00:00:13,905
The virus spread through the air,

4
00:00:13,905 --> 00:00:15,365
attacking the skin cells,

5
00:00:15,365 --> 00:00:16,298
bone marrow,

6
00:00:16,298 --> 00:00:17,026
spleen,

7
00:00:17,026 --> 00:00:19,211
and lymph nodes of its victims.

8
00:00:19,211 --> 00:00:21,828
The unlucky infected developed fevers,

9
00:00:21,828 --> 00:00:22,631
vomiting,

10
00:00:22,631 --> 00:00:23,915
and rashes.

11
00:00:23,915 --> 00:00:26,542
30% of infected people died

12
00:00:26,542 --> 00:00:28,834
during the second week of infection.

13
00:00:28,834 --> 00:00:31,046
Survivors bore scars and scabs

14
00:00:31,046 --> 00:00:32,671
for the rest of their lives.

15
00:00:32,671 --> 00:00:35,210
Smallpox had arrived.

16
00:00:35,210 --> 00:00:39,006
In 1350 B.C., the first smallpox epidemics

17
00:00:39,006 --> 00:00:41,466
hit during the Egypt-Hittite war.

18
00:00:41,466 --> 00:00:43,882
Egyptian prisoners spread smallpox

19
00:00:43,882 --> 00:00:44,962
to the Hittites,

20
00:00:44,962 --> 00:00:46,336
which killed their king

21
00:00:46,336 --> 00:00:48,563
and devastated his civilization.

22
00:00:48,563 --> 00:00:51,816
Insidiously, smallpox made its way around the world

23
00:00:51,816 --> 00:00:53,876
via Egyptian merchants,

24
00:00:53,876 --> 00:00:56,153
then through the Arab world with the Crusades,

25
00:00:56,153 --> 00:00:57,796
and all the way to the Americas

26
00:00:57,796 --> 00:01:00,906
with the Spanish and Portuguese conquests.

27
00:01:00,906 --> 00:01:03,661
Since then, it has killed billions of people

28
00:01:03,661 --> 00:01:06,966
with an estimated 300 to 500 million people

29
00:01:06,966 --> 00:01:09,521
killed in the 20th century alone.

30
00:01:09,521 --> 00:01:12,048
But smallpox is not unbeatable.

31
00:01:12,048 --> 00:01:14,548
In fact, the fall of smallpox started

32
00:01:14,548 --> 00:01:16,376
long before modern medicine.

33
00:01:16,376 --> 00:01:19,586
It began all the way back in 1022 A.D.

34
00:01:19,586 --> 00:01:21,015
According to a small book, called

35
00:01:21,015 --> 00:01:23,025
"The Correct Treatment of Small Pox,"

36
00:01:23,025 --> 00:01:25,121
a Buddhist nun living in a famous mountain

37
00:01:25,121 --> 00:01:26,759
named O Mei Shan

38
00:01:26,759 --> 00:01:28,559
in the southern providence of Sichuan

39
00:01:28,559 --> 00:01:30,367
would grind up smallpox scabs

40
00:01:30,367 --> 00:01:33,096
and blow the powder into nostrils of healthy people.

41
00:01:33,096 --> 00:01:34,605
She did this after noticing

42
00:01:34,605 --> 00:01:36,949
that those who managed to survive smallpox

43
00:01:36,949 --> 00:01:38,336
never got it again,

44
00:01:38,336 --> 00:01:40,357
and her odd treatment worked.

45
00:01:40,357 --> 00:01:42,171
The procedure, called variolation,

46
00:01:42,171 --> 00:01:43,171
slowly evolved

47
00:01:43,171 --> 00:01:44,612
and by the 1700's,

48
00:01:44,612 --> 00:01:46,835
doctors were taking material from sores

49
00:01:46,835 --> 00:01:48,871
and putting them into healthy people

50
00:01:48,871 --> 00:01:51,717
through four or five scratches on the arm.

51
00:01:51,717 --> 00:01:52,752
This worked pretty well

52
00:01:52,752 --> 00:01:55,588
as inoculated people would not get reinfected,

53
00:01:55,588 --> 00:01:57,171
but it wasn't foolproof.

54
00:01:57,171 --> 00:01:58,754
Up to three percent of people

55
00:01:58,754 --> 00:02:02,340
would still die after being exposed to the puss.

56
00:02:02,340 --> 00:02:04,928
It wasn't until English physician Edward Jenner

57
00:02:04,928 --> 00:02:07,253
noticed something interesting about dairy maids

58
00:02:07,253 --> 00:02:09,380
that we got our modern solution.

59
00:02:09,380 --> 00:02:11,727
At age 13, while Jenner was apprentice

60
00:02:11,727 --> 00:02:13,410
to a country surgeon and apothecary

61
00:02:13,410 --> 00:02:15,525
in Sodbury, near Bristol,

62
00:02:15,525 --> 00:02:17,138
he heard a dairy maid say,

63
00:02:17,138 --> 00:02:20,114
"I shall never have smallpox, for I have had cowpox.

64
00:02:20,114 --> 00:02:22,734
I shall never have an ugly, pockmarked face."

65
00:02:22,734 --> 00:02:24,383
Cowpox is a skin disease

66
00:02:24,383 --> 00:02:27,306
that resembles smallpox and infects cows.

67
00:02:27,306 --> 00:02:28,719
Later on, as a physician,

68
00:02:28,719 --> 00:02:30,438
he realized that she was right,

69
00:02:30,438 --> 00:02:32,891
women who got cowpox didn't develop

70
00:02:32,891 --> 00:02:34,391
the deadly smallpox.

71
00:02:34,391 --> 00:02:37,793
Smallpox and cowpox viruses are from the same family.

72
00:02:37,793 --> 00:02:40,345
But when a virus infects an unfamiliar host,

73
00:02:40,345 --> 00:02:42,605
in this case cowpox infecting a human,

74
00:02:42,605 --> 00:02:43,891
it is less virulent,

75
00:02:43,891 --> 00:02:45,359
so Jenner decided to test

76
00:02:45,359 --> 00:02:47,682
whether the cowpox virus could be used

77
00:02:47,682 --> 00:02:50,105
to protect against smallpox.

78
00:02:50,105 --> 00:02:53,379
In May 1796, Jenner found a young dairy maid,

79
00:02:53,379 --> 00:02:54,597
Sarah Nelmes,

80
00:02:54,597 --> 00:02:57,424
who had fresh cowpox lesions on her hand and arm

81
00:02:57,424 --> 00:02:59,842
caught from the utters of a cow named Blossom.

82
00:02:59,842 --> 00:03:01,519
Using matter from her pustules,

83
00:03:01,519 --> 00:03:03,582
he inoculated James Phipps,

84
00:03:03,582 --> 00:03:05,937
the eight-year-old son of his gardener.

85
00:03:05,937 --> 00:03:08,105
After a few days of fever and discomfort,

86
00:03:08,105 --> 00:03:09,932
the boy seemed to recover.

87
00:03:09,932 --> 00:03:12,459
Two months later, Jenner inoculated the boy again,

88
00:03:12,459 --> 00:03:16,340
this time with matter from a fresh smallpox lesion.

89
00:03:16,340 --> 00:03:17,715
No disease developed,

90
00:03:17,715 --> 00:03:20,397
and Jenner concluded that protection was complete.

91
00:03:20,397 --> 00:03:22,129
His plan had worked.

92
00:03:22,129 --> 00:03:24,426
Jenner later used the cowpox virus

93
00:03:24,426 --> 00:03:25,723
in several other people

94
00:03:25,723 --> 00:03:28,219
and challenged them repeatedly with smallpox,

95
00:03:28,219 --> 00:03:30,688
proving that they were immune to the disease.

96
00:03:30,688 --> 00:03:31,816
With this procedure,

97
00:03:31,816 --> 00:03:34,441
Jenner invented the smallpox vaccination.

98
00:03:34,441 --> 00:03:37,436
Unlike variolation, which used actual smallpox virus

99
00:03:37,436 --> 00:03:38,942
to try to protect people,

100
00:03:38,942 --> 00:03:42,569
vaccination used the far less dangerous cowpox virus.

101
00:03:42,569 --> 00:03:43,773
The medical establishment,

102
00:03:43,773 --> 00:03:45,406
cautious then as now,

103
00:03:45,406 --> 00:03:47,788
deliberated at length over his findings

104
00:03:47,788 --> 00:03:49,160
before accepting them.

105
00:03:49,160 --> 00:03:52,220
But eventually vaccination was gradually accepted

106
00:03:52,220 --> 00:03:54,640
and variolation became prohibited

107
00:03:54,064 --> 00:03:55,908
in England in 1840.

108
00:03:55,908 --> 00:03:57,753
After large vaccination campaigns

109
00:03:57,753 --> 00:04:00,530
throughout the 19th and 20th centuries,

110
00:04:00,530 --> 00:04:02,228
the World Health Organization certified

111
00:04:02,228 --> 00:04:05,712
smallpox's eradication in 1979.

112
00:04:05,712 --> 00:04:07,083
Jenner is forever remembered

113
00:04:07,083 --> 00:04:09,076
as the father of immunology,

114
00:04:09,076 --> 00:04:11,352
but let's not forget the dairy maid Sarah Nelmes,

115
00:04:11,352 --> 00:04:12,438
Blossom the cow,

116
00:04:12,438 --> 00:04:13,640
and James Phipps,

117
00:04:13,640 --> 00:04:16,359
all heroes in this great adventure of vaccination

118
00:04:16,359 --> 00:04:18,236
who helped eradicate smallpox.