WEBVTT 00:00:00.000 --> 00:00:07.280 align:middle line:90% [PLAYING MUSIC] 00:00:07.280 --> 00:00:08.780 align:middle line:84% OLAKUNLE ALONGE: So here we're going 00:00:08.780 --> 00:00:13.440 align:middle line:84% to be talking about some basic facts around polio 00:00:13.440 --> 00:00:17.180 align:middle line:84% as a disease-causing agent; poliomyelitis, 00:00:17.180 --> 00:00:19.760 align:middle line:84% the disease that the polio virus causes; 00:00:19.760 --> 00:00:24.340 align:middle line:84% and the polio eradication initiative. 00:00:24.340 --> 00:00:28.770 align:middle line:84% Here you see the micrograph of the polio virus, which 00:00:28.770 --> 00:00:34.080 align:middle line:84% is a single-stranded RNA, so basically the virus 00:00:34.080 --> 00:00:37.365 align:middle line:84% is the genetic material [INAUDIBLE] RNA material 00:00:37.365 --> 00:00:38.130 align:middle line:90% itself. 00:00:38.130 --> 00:00:42.900 align:middle line:84% But it belongs to the family of the [INAUDIBLE] 00:00:42.900 --> 00:00:46.530 align:middle line:84% family of the enteroviruses and to the other types 00:00:46.530 --> 00:00:48.160 align:middle line:90% of enteroviruses. 00:00:48.160 --> 00:00:52.410 align:middle line:84% And "entero," meaning mounts and the GI tract, 00:00:52.410 --> 00:00:55.020 align:middle line:84% so those viruses are transmittable 00:00:55.020 --> 00:00:59.240 align:middle line:84% through the ingestion of contaminated food and water. 00:00:59.240 --> 00:01:01.310 align:middle line:84% And this is really important to understand 00:01:01.310 --> 00:01:03.810 align:middle line:84% as we begin to think about the biology 00:01:03.810 --> 00:01:08.090 align:middle line:84% because it's an organic virus, it's really-- 00:01:08.090 --> 00:01:10.850 align:middle line:84% in the process of transcription, it's 00:01:10.850 --> 00:01:15.215 align:middle line:84% a lot less stable compared to a DNA virus. 00:01:15.215 --> 00:01:16.590 align:middle line:84% So what happens is that you could 00:01:16.590 --> 00:01:20.430 align:middle line:84% have passage of a mutation is actually high, 00:01:20.430 --> 00:01:25.290 align:middle line:84% and it has implications for the stability of the vaccines 00:01:25.290 --> 00:01:28.250 align:middle line:84% that are derived for the virus and also 00:01:28.250 --> 00:01:32.460 align:middle line:84% on the virulence in terms of how harmful 00:01:32.460 --> 00:01:36.660 align:middle line:84% the virus is as [? it's ?] transmit or replicate 00:01:36.660 --> 00:01:38.350 align:middle line:90% over time. 00:01:38.350 --> 00:01:42.690 align:middle line:84% So let's talk a little bit more about the viruses. 00:01:42.690 --> 00:01:47.430 align:middle line:84% So as I said earlier on, the polio virus, it's an RNA virus 00:01:47.430 --> 00:01:49.830 align:middle line:84% and there are three major strains. 00:01:49.830 --> 00:01:52.230 align:middle line:84% The strains are distinguish based 00:01:52.230 --> 00:01:53.990 align:middle line:84% on their genetic properties, so they 00:01:53.990 --> 00:01:56.550 align:middle line:84% are distinguishable in terms of their 00:01:56.550 --> 00:02:00.360 align:middle line:84% having a basis within each of their different types of RNA. 00:02:00.360 --> 00:02:02.470 align:middle line:84% So you have the wild polio type 1, 00:02:02.470 --> 00:02:05.320 align:middle line:84% which is often regarded as the most virulent. 00:02:05.320 --> 00:02:07.490 align:middle line:84% [? Its ?] status, currently endemic-- 00:02:07.490 --> 00:02:11.820 align:middle line:84% in fact, it's the only still-occuring wild polio virus 00:02:11.820 --> 00:02:13.440 align:middle line:90% that we have in the world. 00:02:13.440 --> 00:02:17.120 align:middle line:84% It's endemic in Afghanistan and in Pakistan. 00:02:17.120 --> 00:02:20.830 align:middle line:84% And the other type 2, which is the least virulent-- 00:02:20.830 --> 00:02:22.333 align:middle line:90% and this has been eradicated. 00:02:22.333 --> 00:02:24.030 align:middle line:84% This incidence of this is completely 00:02:24.030 --> 00:02:25.460 align:middle line:90% zero across the globe. 00:02:25.460 --> 00:02:29.580 align:middle line:84% It was last detected in India in 1999. 00:02:29.580 --> 00:02:32.610 align:middle line:84% And then we have the wild poliovirus type 3 00:02:32.610 --> 00:02:37.110 align:middle line:84% which was declared eradicated in 2019. 00:02:37.110 --> 00:02:39.420 align:middle line:84% So again, there are genetic materials 00:02:39.420 --> 00:02:43.790 align:middle line:84% that are different between each of these different substrate, 00:02:43.790 --> 00:02:48.030 align:middle line:84% and that actually qualifies the differences in the virulence, 00:02:48.030 --> 00:02:51.470 align:middle line:90% comparing one strain to another. 00:02:51.470 --> 00:02:54.110 align:middle line:84% Like I said earlier on, these viruses 00:02:54.110 --> 00:02:58.100 align:middle line:84% are transmitted through the fecal-oral route. 00:02:58.100 --> 00:03:02.840 align:middle line:84% So that is to say that they are found in contaminated-- 00:03:02.840 --> 00:03:07.550 align:middle line:84% so when somebody who carries the virus, when they ingest 00:03:07.550 --> 00:03:10.670 align:middle line:84% or when sanitary measures are not put in place for 00:03:10.670 --> 00:03:13.860 align:middle line:84% toilets and so on, they can contaminate 00:03:13.860 --> 00:03:16.790 align:middle line:90% water sources and food supply. 00:03:16.790 --> 00:03:18.890 align:middle line:84% And then when an uninfected person 00:03:18.890 --> 00:03:23.120 align:middle line:84% ingests the water or the food, the virus 00:03:23.120 --> 00:03:26.190 align:middle line:84% lodge within the gastrointestinal tract, 00:03:26.190 --> 00:03:29.920 align:middle line:84% that is to say the stomach, the intestine, [INAUDIBLE] 00:03:29.920 --> 00:03:33.470 align:middle line:84% intestine, the small intestine, the large intestine, 00:03:33.470 --> 00:03:34.940 align:middle line:90% of the individual. 00:03:34.940 --> 00:03:39.620 align:middle line:84% And the virus uses the machinery for replication, 00:03:39.620 --> 00:03:44.540 align:middle line:84% forms the host, and continues to propagate itself and multiply. 00:03:44.540 --> 00:03:48.170 align:middle line:84% So the individual sheds viruses when they ingest. 00:03:48.170 --> 00:03:51.340 align:middle line:84% And at the same time, the virus come from the intestinal tract 00:03:51.340 --> 00:03:53.600 align:middle line:90% going to the bloodstream. 00:03:53.600 --> 00:03:55.370 align:middle line:84% And then from the bloodstream, the virus 00:03:55.370 --> 00:04:00.320 align:middle line:84% goes into the nerves, which are the areas that are mostly 00:04:00.320 --> 00:04:01.320 align:middle line:90% affected. 00:04:01.320 --> 00:04:03.710 align:middle line:84% And so from the nerves, the virus 00:04:03.710 --> 00:04:06.700 align:middle line:84% usually travels to the spinal cord 00:04:06.700 --> 00:04:11.040 align:middle line:84% where the nerves originate from and destroys the motor neuron, 00:04:11.040 --> 00:04:14.900 align:middle line:84% that is, the nerves that controls the skeletal muscles 00:04:14.900 --> 00:04:16.170 align:middle line:90% within the spinal cord. 00:04:16.170 --> 00:04:18.560 align:middle line:84% And that's why you have your paralysis. 00:04:18.560 --> 00:04:21.990 align:middle line:84% So you can see that based on the transmission of the virus, 00:04:21.990 --> 00:04:23.990 align:middle line:84% you can begin to understand what some 00:04:23.990 --> 00:04:26.090 align:middle line:84% of the clinical manifestations can be. 00:04:26.090 --> 00:04:29.330 align:middle line:84% Because the viruses replicates in the intestine, 00:04:29.330 --> 00:04:32.810 align:middle line:84% you could have some gastrointestinal symptoms 00:04:32.810 --> 00:04:35.750 align:middle line:84% including vomiting and upset when somebody 00:04:35.750 --> 00:04:37.370 align:middle line:90% is infected with the virus. 00:04:37.370 --> 00:04:40.340 align:middle line:84% Because the viruses affects the nerves 00:04:40.340 --> 00:04:44.060 align:middle line:84% and it affects the motor neuron that control the nerves, 00:04:44.060 --> 00:04:46.640 align:middle line:84% you could have irritation of the spinal cord, which 00:04:46.640 --> 00:04:49.280 align:middle line:84% presents as meningitis or meninges [INAUDIBLE].. 00:04:49.280 --> 00:04:52.160 align:middle line:84% And you could also have paralysis 00:04:52.160 --> 00:04:56.040 align:middle line:84% when there is affectation of the anterior motor neuron. 00:04:56.040 --> 00:04:58.160 align:middle line:84% So I'll say again, the transmission 00:04:58.160 --> 00:05:01.220 align:middle line:84% routes for the virus, or the transmission 00:05:01.220 --> 00:05:03.470 align:middle line:84% of the virus and the routes that the virus takes 00:05:03.470 --> 00:05:05.870 align:middle line:84% within the human body, can actually 00:05:05.870 --> 00:05:11.060 align:middle line:84% shed light on to the clinical manifestation of the virus. 00:05:11.060 --> 00:05:14.060 align:middle line:84% Now, one of the cardinal criteria for eradication 00:05:14.060 --> 00:05:18.440 align:middle line:84% is that humans supposedly should be the only reservoir 00:05:18.440 --> 00:05:19.550 align:middle line:90% for the virus. 00:05:19.550 --> 00:05:21.980 align:middle line:84% And this applies to polio, that is 00:05:21.980 --> 00:05:26.790 align:middle line:84% to say that humans are the only susceptible host to the virus. 00:05:26.790 --> 00:05:30.418 align:middle line:84% I mean this is as of the time when the Eradication 00:05:30.418 --> 00:05:31.710 align:middle line:90% Initiative would have been set. 00:05:31.710 --> 00:05:35.240 align:middle line:84% and the virus only replicates in the host. 00:05:35.240 --> 00:05:37.900 align:middle line:84% But in recent times, we know that there 00:05:37.900 --> 00:05:41.690 align:middle line:84% are signs that maybe perhaps, just yet uncertain, 00:05:41.690 --> 00:05:45.350 align:middle line:84% the virus may actually amplify in the environment, even 00:05:45.350 --> 00:05:46.430 align:middle line:90% outside of humans. 00:05:46.430 --> 00:05:49.190 align:middle line:84% But again, based on the biology, we 00:05:49.190 --> 00:05:51.770 align:middle line:84% know that humans are the only reservoir. 00:05:51.770 --> 00:05:53.410 align:middle line:84% So that is to say that if you were 00:05:53.410 --> 00:05:57.800 align:middle line:84% able to eliminate the incidents among humans, 00:05:57.800 --> 00:06:01.890 align:middle line:84% we would eliminate the virus from the face of the earth. 00:06:01.890 --> 00:06:03.990 align:middle line:84% Back to the clinical manifestation, 00:06:03.990 --> 00:06:06.010 align:middle line:84% as I described earlier on, the virus 00:06:06.010 --> 00:06:08.870 align:middle line:84% is really replicates in the intestine, 00:06:08.870 --> 00:06:11.760 align:middle line:84% and from the intestine, gets into the bloodstream. 00:06:11.760 --> 00:06:14.970 align:middle line:84% Some from there travels through the nerve 00:06:14.970 --> 00:06:18.630 align:middle line:84% to get to the spinal cord, and then infects the motor neuron 00:06:18.630 --> 00:06:20.950 align:middle line:90% cells within the spinal cord. 00:06:20.950 --> 00:06:23.700 align:middle line:84% But this is really weird, because indeed, 00:06:23.700 --> 00:06:29.160 align:middle line:84% in 99% of infection, we do not see any paralysis. 00:06:29.160 --> 00:06:34.200 align:middle line:84% In fact, in about 74% of people that are infected, 00:06:34.200 --> 00:06:37.470 align:middle line:84% there is no upper end symptoms or signs. 00:06:37.470 --> 00:06:39.490 align:middle line:84% There is nothing to suggest that they 00:06:39.490 --> 00:06:41.530 align:middle line:90% are infected with the polio. 00:06:41.530 --> 00:06:43.260 align:middle line:84% And this is really important because this 00:06:43.260 --> 00:06:44.677 align:middle line:84% is some of the things that present 00:06:44.677 --> 00:06:46.780 align:middle line:90% challenges for eradication. 00:06:46.780 --> 00:06:48.460 align:middle line:84% So for you to eradicate a disease, 00:06:48.460 --> 00:06:51.930 align:middle line:84% it's a lot easier if you can see when somebody is infected 00:06:51.930 --> 00:06:53.313 align:middle line:84% with the disease, so that we know 00:06:53.313 --> 00:06:54.730 align:middle line:84% and you're able to identify cases. 00:06:54.730 --> 00:06:58.090 align:middle line:84% You're able to isolate, quarantine, and so on. 00:06:58.090 --> 00:07:01.080 align:middle line:84% But in this case, it's an upper end disease 00:07:01.080 --> 00:07:03.240 align:middle line:84% in the vast majority that are infected. 00:07:03.240 --> 00:07:07.140 align:middle line:84% And in about 24% of cases, you have 00:07:07.140 --> 00:07:10.800 align:middle line:84% some very mild, very mild [INAUDIBLE] 00:07:10.800 --> 00:07:15.510 align:middle line:84% typical of any viral infection, so for instance, 00:07:15.510 --> 00:07:20.760 align:middle line:84% when you have stomach upset, vomiting, muscle pain, 00:07:20.760 --> 00:07:22.440 align:middle line:90% headache, and so on. 00:07:22.440 --> 00:07:26.100 align:middle line:84% So this usually sets in between one to five days 00:07:26.100 --> 00:07:29.210 align:middle line:84% after the individual himself is infected. 00:07:29.210 --> 00:07:32.240 align:middle line:84% So in majority of cases, you see that the disease 00:07:32.240 --> 00:07:36.360 align:middle line:84% is in upper end but with no clinical manifestation. 00:07:36.360 --> 00:07:42.060 align:middle line:84% And in some cases, it present as very mild viral illness. 00:07:42.060 --> 00:07:45.540 align:middle line:84% So it's only in the very rare occasion, 00:07:45.540 --> 00:07:49.410 align:middle line:84% so it's only in less than 1%, that you'll have paralysis. 00:07:49.410 --> 00:07:52.900 align:middle line:84% In fact, paralysis due to the wild poliovirus 00:07:52.900 --> 00:07:57.090 align:middle line:84% has been said to occur only in between one out of 100 to one 00:07:57.090 --> 00:08:00.810 align:middle line:84% out of 500 individuals that are infected. 00:08:00.810 --> 00:08:04.130 align:middle line:84% When paralysis do occur, paralysis do occur. 00:08:04.130 --> 00:08:07.440 align:middle line:84% I mean it obviously affects the skeletal muscles given 00:08:07.440 --> 00:08:12.780 align:middle line:84% that the virus infects the anterior motor neuron cells. 00:08:12.780 --> 00:08:15.450 align:middle line:84% And so it affects the muscles that 00:08:15.450 --> 00:08:17.730 align:middle line:84% are voluntary, this voluntary skeletal muscles. 00:08:17.730 --> 00:08:19.970 align:middle line:84% So for instance, muscles of the limbs, 00:08:19.970 --> 00:08:23.190 align:middle line:84% muscles for breathing and swallowing and chewing. 00:08:23.190 --> 00:08:26.880 align:middle line:84% So it can affect both the muscles that control the limbs 00:08:26.880 --> 00:08:29.610 align:middle line:84% and also affects the cranial nerves that 00:08:29.610 --> 00:08:32.005 align:middle line:90% controls swallowing and so on. 00:08:32.005 --> 00:08:35.429 align:middle line:84% And usually, the lower limbs is more affected 00:08:35.429 --> 00:08:39.289 align:middle line:84% when there's paralysis, more than the upper limb. 00:08:39.289 --> 00:08:42.360 align:middle line:84% And you have affectation on the proximal muscles more 00:08:42.360 --> 00:08:43.380 align:middle line:90% than the distal muscles. 00:08:43.380 --> 00:08:46.123 align:middle line:84% So for instance, the thigh is going 00:08:46.123 --> 00:08:48.390 align:middle line:84% to be more affected than the muscles that are farther 00:08:48.390 --> 00:08:50.240 align:middle line:90% away from the spinal cord. 00:08:50.240 --> 00:08:53.700 align:middle line:84% And then in cases where it affects the cranial nerves that 00:08:53.700 --> 00:08:58.050 align:middle line:84% controls breathing, that's where you have the bulbar polio which 00:08:58.050 --> 00:09:01.320 align:middle line:84% can lead to respiratory failure because of the inability 00:09:01.320 --> 00:09:02.240 align:middle line:90% to do it. 00:09:02.240 --> 00:09:05.235 align:middle line:84% So like I said again, [INAUDIBLE] paralysis, 00:09:05.235 --> 00:09:06.930 align:middle line:90% are indeed very rare. 00:09:06.930 --> 00:09:12.810 align:middle line:84% It's a cause in between one in 100 cases to one in 500 cases. 00:09:12.810 --> 00:09:15.210 align:middle line:84% But it's so true that the [? effects ?] of the disease 00:09:15.210 --> 00:09:18.370 align:middle line:84% is really scary, because where you see the paralysis, 00:09:18.370 --> 00:09:20.760 align:middle line:84% it really evokes a lot of terror or fear. 00:09:20.760 --> 00:09:23.270 align:middle line:84% And in cases that paralysis do occur, 00:09:23.270 --> 00:09:26.130 align:middle line:84% the paralysis usually sets in within five days 00:09:26.130 --> 00:09:27.490 align:middle line:90% of the infection. 00:09:27.490 --> 00:09:30.940 align:middle line:84% And usually, if there's ever going to be any recovery, 00:09:30.940 --> 00:09:33.870 align:middle line:84% the recovery would have happened by the end of the month or so. 00:09:33.870 --> 00:09:36.000 align:middle line:90% So most paralysis is permanent. 00:09:36.000 --> 00:09:38.880 align:middle line:84% That is not to say that patients don't continue 00:09:38.880 --> 00:09:42.030 align:middle line:84% to recover over many months, but we 00:09:42.030 --> 00:09:45.750 align:middle line:84% know that whatever recovery that would have happened usually 00:09:45.750 --> 00:09:48.450 align:middle line:84% typically happens within the first [? two ?] month. 00:09:48.450 --> 00:09:49.920 align:middle line:84% Again, when you have the paralysis, 00:09:49.920 --> 00:09:52.830 align:middle line:84% it's called acute flaccid paralysis 00:09:52.830 --> 00:09:56.050 align:middle line:84% because it's acute, because it's rapid onset. 00:09:56.050 --> 00:09:59.080 align:middle line:84% It occurs within five days of infection. 00:09:59.080 --> 00:10:03.060 align:middle line:84% It's flaccid because there's complete weakness 00:10:03.060 --> 00:10:07.230 align:middle line:84% of the skeletal muscles that are used for voluntary action. 00:10:07.230 --> 00:10:10.010 align:middle line:84% But again, to clarify, that is really-- 00:10:10.010 --> 00:10:12.010 align:middle line:84% it's a vehement manifestation of polio, 00:10:12.010 --> 00:10:14.220 align:middle line:84% so many more people who have polio 00:10:14.220 --> 00:10:18.870 align:middle line:84% don't have the manifestation of the paralysis. 00:10:18.870 --> 00:10:24.150 align:middle line:84% Again, this is a very highly resolute picture 00:10:24.150 --> 00:10:25.720 align:middle line:90% of the poliovirus. 00:10:25.720 --> 00:10:28.590 align:middle line:84% So you see, it's really interwoven with RNA 00:10:28.590 --> 00:10:33.110 align:middle line:84% [? --I know-- ?] and kind of interwoven into themselves. 00:10:33.110 --> 00:10:36.630 align:middle line:84% Inside of this is really what holds information 00:10:36.630 --> 00:10:41.740 align:middle line:84% for replication and acquires, admits the host particles 00:10:41.740 --> 00:10:45.110 align:middle line:90% in order to replicate itself. 00:10:45.110 --> 00:10:49.700 align:middle line:84% The history of polio, it's been since the ancient times, 00:10:49.700 --> 00:10:50.810 align:middle line:90% actually. 00:10:50.810 --> 00:10:55.690 align:middle line:84% So we know that even as far back as India in the early BCs 00:10:55.690 --> 00:10:56.560 align:middle line:90% that-- 00:10:56.560 --> 00:10:58.960 align:middle line:84% the hieroglyphics from the Egyptians 00:10:58.960 --> 00:11:01.900 align:middle line:84% really just show [? affectation ?] of polio 00:11:01.900 --> 00:11:07.940 align:middle line:84% even in Egypt, even among the pharaohs of Egypt, way back. 00:11:07.940 --> 00:11:12.040 align:middle line:84% And we recognize that the onset of polio as an epidemic 00:11:12.040 --> 00:11:16.810 align:middle line:84% began to be more noticeable even as sanitation 00:11:16.810 --> 00:11:18.710 align:middle line:90% improves around the world. 00:11:18.710 --> 00:11:24.610 align:middle line:84% So from the 1700s to the 1800s, as societies 00:11:24.610 --> 00:11:26.620 align:middle line:84% were becoming more affluent, given 00:11:26.620 --> 00:11:30.520 align:middle line:84% that the polio is well-linked to unsanitary conditions, 00:11:30.520 --> 00:11:34.510 align:middle line:84% and people were more at risk because of trying 00:11:34.510 --> 00:11:36.490 align:middle line:90% to provide sanitary condition. 00:11:36.490 --> 00:11:38.020 align:middle line:84% Or within the environment, we have 00:11:38.020 --> 00:11:41.450 align:middle line:84% pockets of places where unsanitary conditions allow 00:11:41.450 --> 00:11:42.590 align:middle line:90% some propagation. 00:11:42.590 --> 00:11:44.980 align:middle line:84% So you have a scenario where people are not 00:11:44.980 --> 00:11:48.430 align:middle line:84% widely as exposed to poliovirus as it used to be, 00:11:48.430 --> 00:11:51.940 align:middle line:84% when conditions were likely broadly unsanitary 00:11:51.940 --> 00:11:54.440 align:middle line:84% for most populations, so everybody is exposed. 00:11:54.440 --> 00:11:56.140 align:middle line:84% So we really have people developing 00:11:56.140 --> 00:11:57.950 align:middle line:90% immunity in some ways to that. 00:11:57.950 --> 00:12:02.418 align:middle line:84% So as society began to advance, and prosper, and begin to put 00:12:02.418 --> 00:12:03.960 align:middle line:84% in measures for cleaning [? hands, ?] 00:12:03.960 --> 00:12:08.420 align:middle line:84% for sanitary, for making sure that vomit is clean, 00:12:08.420 --> 00:12:11.850 align:middle line:84% there is less natural exposure to the poliovirus, 00:12:11.850 --> 00:12:15.680 align:middle line:84% and therefore that increased the risk of epidemics. 00:12:15.680 --> 00:12:18.030 align:middle line:84% And that's what we began to see in the United States 00:12:18.030 --> 00:12:21.940 align:middle line:84% and in other parts of the world in the 1700s and the 1800s, 00:12:21.940 --> 00:12:25.990 align:middle line:84% by which time it was really scary because parents 00:12:25.990 --> 00:12:30.490 align:middle line:84% see children were OK, and then suddenly, they couldn't walk. 00:12:30.490 --> 00:12:33.790 align:middle line:84% In some cases, some children had bulbar polio 00:12:33.790 --> 00:12:35.770 align:middle line:90% which affected breathing. 00:12:35.770 --> 00:12:38.313 align:middle line:84% And there was a lot of morbidity and mortality. 00:12:38.313 --> 00:12:39.480 align:middle line:90% So there was a lot of scare. 00:12:39.480 --> 00:12:43.870 align:middle line:84% By the early 1900s, good attention 00:12:43.870 --> 00:12:46.270 align:middle line:84% was brought to the polio by the infection 00:12:46.270 --> 00:12:48.970 align:middle line:84% of Franklin Roosevelt. One of the US president 00:12:48.970 --> 00:12:52.790 align:middle line:84% was infected as an adult at the age of 39. 00:12:52.790 --> 00:12:56.830 align:middle line:84% So in the 1920s, that really brought a lot of attention 00:12:56.830 --> 00:12:58.300 align:middle line:90% to the polio program. 00:12:58.300 --> 00:13:01.540 align:middle line:84% And he also let people just see the disease 00:13:01.540 --> 00:13:05.470 align:middle line:84% from a different perspective and also facilitated and led 00:13:05.470 --> 00:13:08.830 align:middle line:84% a discussion on resources and collaboration. 00:13:08.830 --> 00:13:12.910 align:middle line:84% So by the 1950s, vaccines and injectable vaccines 00:13:12.910 --> 00:13:15.700 align:middle line:84% was developed by Salk, which really helped 00:13:15.700 --> 00:13:19.780 align:middle line:84% to reduce the epidemics of polio in the United States 00:13:19.780 --> 00:13:21.100 align:middle line:90% drastically. 00:13:21.100 --> 00:13:23.770 align:middle line:84% And then in 1963, or thereabouts, 00:13:23.770 --> 00:13:26.990 align:middle line:84% the oral polio vaccine was developed by Sabin. 00:13:26.990 --> 00:13:31.840 align:middle line:84% And this even further helped the elimination 00:13:31.840 --> 00:13:35.620 align:middle line:84% of poliovirus outside of the US, where 00:13:35.620 --> 00:13:37.570 align:middle line:90% it was still a very big issue. 00:13:37.570 --> 00:13:40.990 align:middle line:84% And given the nature of the OPV, Oral Poliovirus, 00:13:40.990 --> 00:13:44.090 align:middle line:84% it could be delivered readily through the mouth, so 00:13:44.090 --> 00:13:48.100 align:middle line:84% that facilitated mass use, mass immunization. 00:13:48.100 --> 00:13:50.770 align:middle line:84% And the development of both of these vaccines 00:13:50.770 --> 00:13:54.460 align:middle line:84% really aided or paved the way for discussion 00:13:54.460 --> 00:13:56.680 align:middle line:84% around the Global Polio Eradication Initiative. 00:13:56.680 --> 00:13:58.990 align:middle line:84% So with the success with vaccination-- 00:13:58.990 --> 00:14:01.120 align:middle line:84% with injectable --in the United States 00:14:01.120 --> 00:14:05.650 align:middle line:84% earlier on and with the Europe polio vaccine globally, 00:14:05.650 --> 00:14:08.710 align:middle line:84% in some parts of the world, [INAUDIBLE] and [INAUDIBLE] 00:14:08.710 --> 00:14:12.080 align:middle line:84% came together in 1988 recognizing that there 00:14:12.080 --> 00:14:13.940 align:middle line:90% is an effective vaccine. 00:14:13.940 --> 00:14:17.225 align:middle line:84% And there's enough commitment to seek eradication of polio 00:14:17.225 --> 00:14:17.850 align:middle line:90% from the world. 00:14:17.850 --> 00:14:20.470 align:middle line:84% So again, a lot of the sources are there 00:14:20.470 --> 00:14:24.010 align:middle line:84% for you to pull from in terms of the history of polio 00:14:24.010 --> 00:14:26.620 align:middle line:84% and how it has evolved and shaped 00:14:26.620 --> 00:14:30.490 align:middle line:90% human society over these years. 00:14:30.490 --> 00:14:33.970 align:middle line:84% This is just to show you some of the early reports 00:14:33.970 --> 00:14:39.220 align:middle line:84% of poliomyelitis in the early 1900s. 00:14:39.220 --> 00:14:43.850 align:middle line:84% We see instances where we had rapid epidemic 00:14:43.850 --> 00:14:47.260 align:middle line:84% of the poliovirus, and then as people 00:14:47.260 --> 00:14:52.950 align:middle line:84% began to know the disease, understand its biology, 00:14:52.950 --> 00:14:55.180 align:middle line:84% the way it transmits in the environment, 00:14:55.180 --> 00:14:57.700 align:middle line:84% and sanitary conditions were put in place. 00:14:57.700 --> 00:15:00.070 align:middle line:84% It was helping with the epidemics to some extent 00:15:00.070 --> 00:15:03.025 align:middle line:84% but at the same time putting more people at risk. 00:15:03.025 --> 00:15:06.430 align:middle line:84% As vaccines [INAUDIBLE] to develop 00:15:06.430 --> 00:15:09.550 align:middle line:84% vaccines were later discovered, it drastically 00:15:09.550 --> 00:15:13.310 align:middle line:84% reduced the incidents of the poliomyelitis cases. 00:15:13.310 --> 00:15:16.420 align:middle line:84% So again, you see the graph, you see its rapid rise 00:15:16.420 --> 00:15:17.720 align:middle line:90% because of the epidemic. 00:15:17.720 --> 00:15:23.490 align:middle line:84% And then it decline as a result of public health measures, 00:15:23.490 --> 00:15:25.515 align:middle line:84% which largely around sanitary and [INAUDIBLE] 00:15:25.515 --> 00:15:26.740 align:middle line:90% sanitary conditions. 00:15:26.740 --> 00:15:31.110 align:middle line:84% And then much later on, use of vaccination really helped. 00:15:31.110 --> 00:15:34.110 align:middle line:84% In low-income, settings the disease is endemic. 00:15:34.110 --> 00:15:39.240 align:middle line:84% And as of 2019, we know that the diseases are endemic largely 00:15:39.240 --> 00:15:43.110 align:middle line:84% in Afghanistan, which is the map that you see here, 00:15:43.110 --> 00:15:44.970 align:middle line:90% and in Pakistan. 00:15:44.970 --> 00:15:48.630 align:middle line:84% I would note that majority of the people that are affected 00:15:48.630 --> 00:15:51.690 align:middle line:90% are infants and young children. 00:15:51.690 --> 00:15:54.090 align:middle line:84% So you have, for instance, in Afghanistan, 00:15:54.090 --> 00:15:59.640 align:middle line:84% as of October 2019, you have your total cases 00:15:59.640 --> 00:16:02.340 align:middle line:84% of wild poliovirus of about 20 children. 00:16:02.340 --> 00:16:06.550 align:middle line:84% And we [INAUDIBLE] looking at not just only the children, 00:16:06.550 --> 00:16:09.280 align:middle line:84% but also looking at samples from the environment, 00:16:09.280 --> 00:16:11.235 align:middle line:90% basically taking sewer samples. 00:16:11.235 --> 00:16:15.780 align:middle line:84% And also showed positivity in specific areas 00:16:15.780 --> 00:16:19.440 align:middle line:84% within Afghanistan, where the samples tested positive 00:16:19.440 --> 00:16:21.450 align:middle line:90% for the poliovirus. 00:16:21.450 --> 00:16:23.370 align:middle line:84% Here, we also see somewhat of a snapshot 00:16:23.370 --> 00:16:26.600 align:middle line:84% of the extent of vaccination and the people that are 00:16:26.600 --> 00:16:28.440 align:middle line:90% involved in the vaccination. 00:16:28.440 --> 00:16:30.220 align:middle line:84% Many of them are females, and so on. 00:16:30.220 --> 00:16:32.220 align:middle line:84% So this is really to show to you, 00:16:32.220 --> 00:16:34.340 align:middle line:84% in places where the disease is still endemic, 00:16:34.340 --> 00:16:38.010 align:middle line:84% there's a lot of ongoing efforts to eliminate 00:16:38.010 --> 00:16:41.730 align:middle line:84% the disease from those areas and then to eradicate the disease 00:16:41.730 --> 00:16:42.565 align:middle line:90% globally. 00:16:42.565 --> 00:16:45.090 align:middle line:84% And this effort really required a lot 00:16:45.090 --> 00:16:50.620 align:middle line:84% of concerted activity of the large swaths of stakeholders 00:16:50.620 --> 00:16:53.370 align:middle line:90% at different level. 00:16:53.370 --> 00:16:56.720 align:middle line:90% [MUSIC PLAYING] 00:16:56.720 --> 00:17:00.000 align:middle line:90%