Romina Libster: The power of herd immunity (with English subtitles) | TED

56,833 views

2015-02-25 ・ TED


New videos

Romina Libster: The power of herd immunity (with English subtitles) | TED

56,833 views ・ 2015-02-25

TED


Please double-click on the English subtitles below to play the video.

00:00
Translator: Gisela Giardino Reviewer: Romina Pol
0
0
7000
00:12
One of the first patients I had to see as a pediatrician was Sol,
1
12280
4780
00:17
a beautiful month-old baby
2
17370
2780
00:20
who was admitted with signs of a severe respiratory infection.
3
20150
3680
00:23
Until then, I had never seen a patient worsen so fast.
4
23830
4280
00:28
In just two days she was connected to a respirator
5
28810
3000
00:31
and on the third day she died.
6
31810
2740
00:34
Sol had whooping cough.
7
34550
2750
00:37
After discussing the case in the room and after a quite distressing catharsis,
8
37300
4710
00:42
I remember my chief resident said to me,
9
42460
2049
00:44
"Okay, take a deep breath. Wash your face.
10
44509
3341
00:48
And now comes the hardest part:
11
48430
2620
00:51
We have to go talk to her parents."
12
51050
2410
00:54
At that time, a thousand questions came to mind,
13
54150
3970
00:58
from, "How could a one-month-old baby be so unfortunate?"
14
58120
4330
01:03
to, "Could we have done something about it?"
15
63200
2870
01:07
Before vaccines existed,
16
67400
2280
01:09
many infectious diseases killed millions of people per year.
17
69680
4870
01:15
During the 1918 flu pandemic
18
75100
3530
01:18
50 million people died.
19
78630
3150
01:21
That's greater than Argentina's current population.
20
81780
3280
01:25
Perhaps, the older ones among you remember the polio epidemic
21
85060
4050
01:29
that occurred in Argentina in 1956.
22
89110
2920
01:32
At that time, there was no vaccine available against polio.
23
92240
3320
01:35
People didn't know what to do. They were going crazy.
24
95560
2530
01:38
They would go painting trees with caustic lime.
25
98090
2280
01:40
They'd put little bags of camphor
26
100370
1570
01:41
in their children's underwear, as if that could do something.
27
101940
3520
01:46
During the polio epidemic, thousands of people died.
28
106080
4520
01:50
And thousands of people were left with very significant neurological damage.
29
110600
4170
01:56
I know this because I read about it,
30
116650
2640
01:59
because thanks to vaccines, my generation was lucky
31
119290
3790
02:03
to not live through an epidemic as terrible as this.
32
123080
2810
02:05
Vaccines are one of the great successes of the 20th century's public health.
33
125890
4790
02:11
After potable water,
34
131210
2020
02:13
they are the interventions that have most reduced mortality,
35
133230
3610
02:16
even more than antibiotics.
36
136840
2130
02:19
Vaccines eradicated terrible diseases such as smallpox from the planet
37
139570
4990
02:24
and succeeded in significantly reducing mortality
38
144590
3610
02:28
due to other diseases such as measles,
39
148200
2250
02:30
whooping cough, polio and many more.
40
150450
3330
02:34
All these diseases are considered vaccine-preventable diseases.
41
154320
6880
02:41
What does this mean?
42
161910
1760
02:43
That they are potentially preventable,
43
163670
3020
02:46
but in order to be so, something must be done.
44
166690
2970
02:49
You need to get vaccinated.
45
169660
2100
02:52
I imagine that most, if not all of us here today,
46
172270
3700
02:55
received a vaccine at some point in our life.
47
175970
3240
03:00
Now, I'm not so sure that many of us know
48
180510
4450
03:04
which vaccines or boosters we should receive after adolescence.
49
184960
4330
03:10
Have you ever wondered who we are protecting
50
190710
4080
03:14
when we vaccinate?
51
194790
1850
03:17
What do I mean by that?
52
197070
1630
03:18
Is there any other effect beyond protecting ourselves?
53
198700
4970
03:25
Let me show you something.
54
205050
2120
03:27
Imagine for a moment
55
207760
2460
03:30
that we are in a city
56
210220
2010
03:32
that has never had a case of a particular disease,
57
212230
3250
03:35
such as the measles.
58
215480
1700
03:37
This would mean that no one in the city has ever had contact with the disease.
59
217430
4860
03:42
No one has natural defenses against, nor been vaccinated against measles.
60
222290
4590
03:47
If one day, a person sick with the measles appears in this city
61
227680
4740
03:53
the disease won't find much resistance
62
233000
3510
03:56
and will begin spreading from person to person,
63
236510
2930
03:59
and in no time it will disseminate throughout the community.
64
239440
4060
04:03
After a certain time
65
243810
1720
04:05
a big part of the population will be ill.
66
245530
3370
04:09
This happened when there were no vaccines.
67
249750
4160
04:14
Now, imagine the complete opposite case.
68
254630
4480
04:19
We are in a city
69
259420
2410
04:21
where more than 90 percent of the population
70
261830
2820
04:24
has defenses against the measles, which means
71
264650
2450
04:27
that they either had the disease, survived, and developed natural defenses;
72
267100
3739
04:30
or that they had been immunized against measles.
73
270839
3701
04:35
If one day,
74
275200
1610
04:36
a person sick with the measles appears in this city,
75
276810
3930
04:41
the disease will find much more resistance
76
281230
3380
04:44
and won't be transmitted that much from person to person.
77
284610
3490
04:48
The spread will probably remain contained
78
288780
3550
04:52
and a measles outbreak won't happen.
79
292750
2930
04:57
I would like you to pay attention to something.
80
297060
2700
05:00
People who are vaccinated
81
300810
2680
05:03
are not only protecting themselves,
82
303490
2800
05:06
but by blocking the dissemination of the disease
83
306290
3610
05:09
within the community,
84
309900
1640
05:11
they are indirectly protecting the people in this community
85
311540
4680
05:16
who are not vaccinated.
86
316220
2170
05:18
They create a kind of protective shield
87
318690
2970
05:21
which prevents them from coming in contact with the disease,
88
321660
3100
05:24
so that these people are protected.
89
324760
2620
05:28
This indirect protection
90
328670
3200
05:31
that the unvaccinated people within a community receive
91
331870
3500
05:35
simply by being surrounded by vaccinated people,
92
335370
4010
05:39
is called herd immunity.
93
339950
3060
05:45
Many people in the community
94
345130
2460
05:47
depend almost exclusively on this herd immunity
95
347590
3500
05:51
to be protected against disease.
96
351090
2660
05:54
The unvaccinated people you see in infographics are not just hypothetical.
97
354760
3960
05:59
Those people are our nieces and nephews, our children,
98
359260
3340
06:02
who may be too young to receive their first shots.
99
362600
3370
06:07
They are our parents, our siblings,
100
367100
2310
06:09
our acquaintances,
101
369410
1430
06:10
who may have a disease,
102
370840
1870
06:12
or take medication that lowers their defenses.
103
372710
3650
06:18
There are also people who are allergic to a particular vaccine.
104
378010
4070
06:23
They could even be among us,
105
383350
2400
06:25
any of us who got vaccinated,
106
385750
1860
06:27
but the vaccine didn't produce the expected effect,
107
387610
3800
06:31
because not all vaccines are always 100 percent effective.
108
391410
4190
06:35
All these people depend almost exclusively on herd immunity
109
395600
5200
06:40
to be protected against diseases.
110
400800
2560
06:44
To achieve this effect of herd immunity,
111
404390
4810
06:49
it is necessary that a large percentage of the population be vaccinated.
112
409200
4670
06:54
This percentage is called the threshold.
113
414500
3070
06:57
The threshold depends on many variables:
114
417570
3760
07:01
It depends on the germ's characteristics,
115
421330
2410
07:03
and those of the immune response that the vaccine generates.
116
423740
4300
07:08
But they all have something in common.
117
428040
2390
07:10
If the percentage of the population in a vaccinated community
118
430430
5210
07:15
is below this threshold number,
119
435980
3070
07:19
the disease will begin to spread more freely
120
439050
4060
07:23
and may generate an outbreak of this disease within the community.
121
443110
4670
07:27
Even diseases which were at some point controlled may reappear.
122
447780
7080
07:36
This is not just a theory.
123
456550
2190
07:38
This has happened, and is still happening.
124
458740
2360
07:43
In 1998, a British researcher published an article
125
463050
4700
07:47
in one of the most important medical journals,
126
467750
2780
07:50
saying that the MMR vaccine,
127
470530
2620
07:53
which is given for measles, mumps and rubella,
128
473150
2730
07:55
was associated with autism.
129
475880
1870
07:57
This generated an immediate impact.
130
477750
2700
08:01
People began to stop getting vaccinated, and stopped vaccinating their children.
131
481010
4650
08:05
And what happened?
132
485680
1620
08:07
The number of people vaccinated,
133
487300
2680
08:09
in many communities around the world, fell below this threshold.
134
489980
3980
08:13
And there were outbreaks of measles in many cities in the world --
135
493960
3560
08:17
in the U.S., in Europe.
136
497520
2440
08:19
Many people got sick.
137
499960
2160
08:22
People died of measles.
138
502120
2780
08:25
What happened?
139
505870
1480
08:27
This article also generated a huge stir within the medical community.
140
507350
4120
08:32
Dozens of researchers began to assess if this was actually true.
141
512020
3670
08:37
Not only could no one find
142
517130
3290
08:40
a causal association between MMR and autism at the population level,
143
520420
5249
08:45
but it was also found that this article had incorrect claims.
144
525669
4901
08:50
Even more, it was fraudulent.
145
530820
2550
08:54
It was fraudulent.
146
534120
2390
08:57
In fact, the journal publicly retracted the article in 2010.
147
537120
6430
09:04
One of the main concerns and excuses for not getting vaccinated
148
544880
3900
09:08
are the adverse effects.
149
548780
2190
09:11
Vaccines, like other drugs, can have potential adverse effects.
150
551770
5640
09:17
Most are mild and temporary.
151
557970
2510
09:20
But the benefits are always greater than possible complications.
152
560480
5990
09:27
When we are ill, we want to heal fast.
153
567740
4560
09:32
Many of us who are here
154
572300
2120
09:34
take antibiotics when we have an infection,
155
574420
3670
09:38
we take anti-hypertensives when we have high blood pressure,
156
578090
3180
09:41
we take cardiac medications.
157
581270
2180
09:43
Why? Because we are sick and we want to heal fast.
158
583450
3250
09:46
And we don't question it much.
159
586700
2020
09:48
Why is it so difficult to think of preventing diseases,
160
588720
4430
09:53
by taking care of ourselves when we are healthy?
161
593890
3210
09:57
We take care of ourselves a lot when affected by an illness,
162
597100
3190
10:00
or in situations of imminent danger.
163
600290
2960
10:04
I imagine most of us here,
164
604140
2670
10:06
remember the influenza-A pandemic
165
606810
3730
10:10
which broke out in 2009 in Argentina and worldwide.
166
610540
3390
10:14
When the first cases began to come to light,
167
614490
3030
10:17
we, here in Argentina, were entering the winter season.
168
617520
3840
10:21
We knew absolutely nothing.
169
621910
2210
10:24
Everything was a mess.
170
624120
1410
10:25
People wore masks on the street, ran into pharmacies to buy alcohol gel.
171
625530
5370
10:30
People would line up in pharmacies to get a vaccine,
172
630900
3350
10:34
without even knowing if it was the right vaccine
173
634250
2560
10:36
that would protect them against this new virus.
174
636810
2540
10:39
We knew absolutely nothing.
175
639350
2300
10:41
At that time, in addition to doing my fellowship at the Infant Foundation,
176
641650
4830
10:46
I worked as a home pediatrician for a prepaid medicine company.
177
646740
3910
10:51
I remember that I started my shift at 8 a.m.,
178
651670
3240
10:54
and by 8, I already had a list of 50 scheduled visits.
179
654910
4150
10:59
It was chaos; people didn't know what to do.
180
659060
2880
11:02
I remember the types of patients that I was examining.
181
662860
4550
11:07
The patients were a little older than what we were used to seeing in winter,
182
667690
4360
11:12
with longer fevers.
183
672050
2340
11:14
And I mentioned that to my fellowship mentor,
184
674390
3680
11:18
and he, for his part, had heard the same from a colleague,
185
678070
3520
11:21
about the large number of pregnant women
186
681590
2730
11:24
and young adults
187
684320
1690
11:26
being hospitalized in intensive care,
188
686010
2240
11:28
with hard-to-manage clinical profiles.
189
688250
2910
11:32
At that time, we set out to understand what was happening.
190
692760
5840
11:39
First thing Monday morning, we took the car
191
699300
3120
11:42
and went to a hospital in Buenos Aires Province,
192
702420
2930
11:45
that served as a referral hospital for cases of the new influenza virus.
193
705350
5670
11:51
We arrived at the hospital; it was crowded.
194
711020
2530
11:53
All health staff were dressed in NASA-like bio-safety suits.
195
713550
3920
11:57
We all had face masks in our pockets.
196
717470
2200
11:59
I, being a hypochondriac, didn't breathe for two hours.
197
719670
2730
12:02
But we could see what was happening.
198
722400
3120
12:05
Immediately, we started reaching out to pediatricians
199
725520
3690
12:09
from six hospitals in the city and in Buenos Aires Province.
200
729210
4220
12:13
Our main goal was to find out
201
733440
3330
12:16
how this new virus behaved in contact with our children,
202
736770
3890
12:20
in the shortest time possible.
203
740660
2580
12:23
A marathon work.
204
743240
2960
12:26
In less than three months,
205
746200
2870
12:29
we could see what effect this new H1N1 virus had
206
749070
6090
12:35
on the 251 children hospitalized by this virus.
207
755160
6140
12:41
We could see which children got more seriously ill:
208
761520
3980
12:45
children under four, especially those less than one year old;
209
765500
3620
12:49
patients with neurological diseases;
210
769120
2800
12:51
and young children with chronic pulmonary diseases.
211
771920
3290
12:55
Identifying these at-risk groups was important
212
775210
4810
13:00
to include them as priority groups
213
780020
2710
13:02
in the recommendations for getting the influenza vaccine,
214
782730
3000
13:05
not only here in Argentina,
215
785730
1860
13:07
but also in other countries which the pandemic not yet reached.
216
787590
4060
13:12
A year later,
217
792750
1680
13:14
when a vaccine against the pandemic H1N1 virus became available,
218
794430
5090
13:19
we wanted to see what happened.
219
799520
2720
13:22
After a huge vaccination campaign
220
802240
3170
13:25
aimed at protecting at-risk groups,
221
805410
4770
13:30
these hospitals, with 93 percent of the at-risk groups vaccinated,
222
810180
6960
13:37
had not hospitalized a single patient
223
817140
3630
13:40
for the pandemic H1N1 virus.
224
820770
2680
13:43
(Applause)
225
823450
3050
13:47
In 2009: 251.
226
827920
3960
13:53
In 2010: zero.
227
833490
2950
13:56
Vaccination is an act of individual responsibility,
228
836440
4780
14:01
but it has a huge collective impact.
229
841220
4030
14:06
If I get vaccinated, not only am I protecting myself,
230
846790
4620
14:11
but I am also protecting others.
231
851420
3210
14:15
Sol had whooping cough.
232
855520
2370
14:19
Sol was very young,
233
859500
2200
14:21
and she hadn't yet received her first vaccine against whooping cough.
234
861700
4530
14:27
I still wonder what would have happened
235
867160
3800
14:30
if everyone around Sol had been vaccinated.
236
870960
5910
14:37
(Applause)
237
877740
2060
About this website

This site will introduce you to YouTube videos that are useful for learning English. You will see English lessons taught by top-notch teachers from around the world. Double-click on the English subtitles displayed on each video page to play the video from there. The subtitles scroll in sync with the video playback. If you have any comments or requests, please contact us using this contact form.

https://forms.gle/WvT1wiN1qDtmnspy7