1
00:00:00,077 --> 00:00:02,637
Recently there has been
a lot of talk about measles.

2
00:00:02,885 --> 00:00:07,040
What does measles actually do,
and should you vaccinate against it?

3
00:00:07,040 --> 00:00:08,838
Or is this just hysteria?

4
00:00:15,797 --> 00:00:17,556
Measles is a virus:

5
00:00:17,556 --> 00:00:19,515
a hull of proteins, RNA,

6
00:00:19,515 --> 00:00:21,660
plus some more proteins for reproduction.

7
00:00:22,030 --> 00:00:25,719
It cannot reproduce by itself;
it needs a host cell to do so.

8
00:00:26,019 --> 00:00:29,788
To understand measles, we have to
understand the immune system.

9
00:00:30,018 --> 00:00:31,353
You might already have seen

10
00:00:31,353 --> 00:00:33,427
the visual system we developed
to help here.

11
00:00:33,837 --> 00:00:37,980
Now, let’s focus on the parts of
the immune system relevant to measles.

12
00:00:38,350 --> 00:00:41,904
The measles virus enters humans
through the nose, mouth, or eyes.

13
00:00:42,184 --> 00:00:44,328
The measles infection starts in the lungs.

14
00:00:44,808 --> 00:00:48,511
Measles is especially good at infecting
the body’s first line of defence:

15
00:00:48,511 --> 00:00:52,833
macrophages, powerful guard cells
that protect the lungs from intruders.

16
00:00:52,972 --> 00:00:54,896
They enter a cell and take it over.

17
00:00:55,346 --> 00:00:57,255
The virus reprograms the cell and

18
00:00:57,255 --> 00:01:00,637
transforms it into a dangerous
virus production center.

19
00:01:00,979 --> 00:01:03,134
Once a cell is filled with viruses,

20
00:01:03,134 --> 00:01:06,843
they leave the crippled cell
and begin the cycle over again.

21
00:01:07,213 --> 00:01:10,930
But the immune system has
powerful weapons against virus infections:

22
00:01:10,930 --> 00:01:12,356
natural killer cells.

23
00:01:12,696 --> 00:01:17,056
These cells basically patrol the body
and check other cells for infections.

24
00:01:17,326 --> 00:01:21,370
If they find an infected cell,
they order it to commit suicide.

25
00:01:21,730 --> 00:01:24,772
This is so effective that for
the first 10 days or so,

26
00:01:24,772 --> 00:01:27,709
you will not even notice that
you’re infected with measles.

27
00:01:28,079 --> 00:01:31,644
And now, the reason why measles
is so powerful.

28
00:01:31,984 --> 00:01:33,824
After a period of fighting and dying,

29
00:01:33,824 --> 00:01:36,606
macrophages alert the brain of the
immune system:

30
00:01:36,606 --> 00:01:37,818
the dendritic cells.

31
00:01:38,068 --> 00:01:41,698
The job of the dendritic cells is
to collect samples of intruders,

32
00:01:41,698 --> 00:01:42,950
travel to the lymph nodes,

33
00:01:42,950 --> 00:01:44,903
and then activate the heavy weapons

34
00:01:44,903 --> 00:01:48,084
that eradicate the infection very fast
in a team effort.

35
00:01:48,604 --> 00:01:52,120
But the measles virus uses
a dreadful tactic.

36
00:01:52,410 --> 00:01:54,050
It infects the dendritic cells

37
00:01:54,050 --> 00:01:57,791
and uses them as a Trojan horse
to enter deeper into the body.

38
00:01:58,161 --> 00:02:00,834
The infected cells travel to the next 
lymph node

39
00:02:00,834 --> 00:02:02,479
to alert other immune cells.

40
00:02:02,719 --> 00:02:03,784
Once it arrives,

41
00:02:03,784 --> 00:02:07,482
the measles virus spreads around the
virgin T and B cells

42
00:02:07,482 --> 00:02:08,820
and infects them.

43
00:02:08,960 --> 00:02:12,103
It attacks the very system that
evolved to fight it.

44
00:02:12,403 --> 00:02:14,224
Now, things happen very fast.

45
00:02:14,354 --> 00:02:16,704
The lymph system spreads the virus
everywhere

46
00:02:16,704 --> 00:02:18,168
and it enters the bloodstream,

47
00:02:18,168 --> 00:02:19,906
infecting cells while traveling.

48
00:02:19,906 --> 00:02:21,469
Measles infects organs like

49
00:02:21,469 --> 00:02:25,043
the spleen, the liver, the intestines,
and, most importantly, the lungs.

50
00:02:25,043 --> 00:02:26,297
The symptoms range from

51
00:02:26,297 --> 00:02:30,356
a very high fever, headache, sickness,
bronchitis, and, of course, a rash.

52
00:02:30,356 --> 00:02:33,209
In the lungs, the immune system was
doing pretty okay.

53
00:02:33,209 --> 00:02:35,955
But now, millions of viruses
attack a second time

54
00:02:35,955 --> 00:02:39,066
and kill countless cells, wiping out
the defense systems.

55
00:02:39,486 --> 00:02:43,044
In this phase, you start coughing out
millions of measles viruses.

56
00:02:43,634 --> 00:02:45,976
Measles is so contagious at this stage,

57
00:02:45,976 --> 00:02:48,180
that if you meet someone
who isn’t vaccinated,

58
00:02:48,180 --> 00:02:51,349
there’s about a 90% chance
you’ll infect them.

59
00:02:51,739 --> 00:02:55,426
Without the protective army in the lungs,
other bacteria or viruses that

60
00:02:55,426 --> 00:02:59,198
would usually not stand a chance can
now enter the lungs and develop into

61
00:02:59,198 --> 00:03:02,093
harmful parallel infections that
can cause pneumonia,

62
00:03:02,093 --> 00:03:04,254
the most common way to
die from measles.

63
00:03:04,714 --> 00:03:07,648
Your body’s immune system is now
seriously wounded.

64
00:03:07,648 --> 00:03:10,827
Various protective systems are hurt
and disrupted.

65
00:03:10,827 --> 00:03:14,956
The virus spreads everywhere, infecting
the skin all over the body.

66
00:03:15,346 --> 00:03:18,105
The typical measles rash now
becomes visible.

67
00:03:18,375 --> 00:03:20,845
And in some cases, the measles virus

68
00:03:20,845 --> 00:03:23,710
reaches the brain and causes
a brain infection.

69
00:03:24,020 --> 00:03:28,004
If it does so, the chances of dying
are between 20 to 40 percent,

70
00:03:28,004 --> 00:03:30,097
and there may be long-term damage.

71
00:03:30,417 --> 00:03:32,991
But your body is far from giving
up at this stage,

72
00:03:32,991 --> 00:03:34,963
and it fights back agressively.

73
00:03:35,373 --> 00:03:38,625
Some dendritic cells survive
long enough to activate

74
00:03:38,625 --> 00:03:40,689
the anti-virus forces of the body.

75
00:03:41,045 --> 00:03:45,148
Plasma cells in the lymph nodes
start producing billions of antibodies,

76
00:03:45,148 --> 00:03:48,586
tiny proteins that mark infected cells
for destruction

77
00:03:48,586 --> 00:03:50,417
or clump the virus together.

78
00:03:50,653 --> 00:03:54,461
Killer T cells flood the body
and kill infected cells left and right.

79
00:03:54,721 --> 00:03:57,157
After 2 to 3 weeks, the body usually gets

80
00:03:57,157 --> 00:03:59,609
the upper hand and overwhelms
the infection.

81
00:03:59,609 --> 00:04:01,942
But the immune system is now
seriously weakened,

82
00:04:01,942 --> 00:04:04,432
and may take weeks or months to recover,

83
00:04:04,432 --> 00:04:07,143
leaving the body vulnerable
to other diseases.

84
00:04:07,543 --> 00:04:10,588
But, if you make it, you are now immune:

85
00:04:10,588 --> 00:04:13,290
the immune system remembers
the virus forever.

86
00:04:13,892 --> 00:04:15,295
Measles is no joke.

87
00:04:15,515 --> 00:04:19,435
Although 84% of all humans are
vaccinated against measles,

88
00:04:19,435 --> 00:04:23,959
122,000 people died because
of the infection in 2014.

89
00:04:24,209 --> 00:04:26,047
Some people cannot get vaccinations,

90
00:04:26,047 --> 00:04:29,844
either because they’re too young,
because of chemotherapy or HIV,

91
00:04:29,844 --> 00:04:31,822
or because they’re allergic
to the vaccine.

92
00:04:32,209 --> 00:04:34,967
They need the rest of us to
stop the disease for them.

93
00:04:35,497 --> 00:04:38,846
The measles vaccination is
safe, cheap, and available.

94
00:04:39,086 --> 00:04:41,488
There are no benifits from having
measles at all.

95
00:04:41,488 --> 00:04:45,303
You don’t strengthen your immune
system and it’s not more natural.

96
00:04:45,593 --> 00:04:48,978
Most people who don’t vaccinate
only want the best for their children,

97
00:04:48,978 --> 00:04:49,970
which is honorable.

98
00:04:49,970 --> 00:04:51,160
But if you ask yourself,

99
00:04:51,160 --> 00:04:54,231
“Am I putting the life of my child
and other children at risk by

100
00:04:54,231 --> 00:04:55,930
not vaccinating against measles?”

101
00:04:56,380 --> 00:04:59,624
The sad answer is yes. Yes, you are.

102
00:04:59,794 --> 00:05:01,761
Let’s not play the blame game, though.

103
00:05:01,761 --> 00:05:04,391
Let’s work together and
eradicate this virus.

104
00:05:04,391 --> 00:05:07,173
Together, we can get rid of these
dreadful monsters and

105
00:05:07,173 --> 00:05:10,220
consign them to their rightful place:
the history books.