WEBVTT - Ep 26 Vaccines part 1: Let's hear it for Maurice 0:00:01.080 --> 0:00:04.000 I am one of the increasingly rare old timers who 0:00:04.040 --> 0:00:07.640 lived during the pre vaccination era. I am the second 0:00:07.680 --> 0:00:10.840 to the last of thirteen siblings, five of whom died 0:00:10.920 --> 0:00:15.800 of vaccine preventable diseases in infancy, born to poor immigrant parents. 0:00:15.920 --> 0:00:18.400 I remember well my mother's account of the causes of 0:00:18.440 --> 0:00:24.400 their deaths, three from protessis and two from measles. Even 0:00:24.480 --> 0:00:27.160 after many years had passed, she spoke of the death 0:00:27.160 --> 0:00:30.240 of her angels with a great deal of emotion. Imagine 0:00:30.240 --> 0:00:35.520 losing not one, two, three, or four, but five babies. 0:00:36.240 --> 0:00:39.640 It was common in the pre vaccine era. Like our family, 0:00:39.800 --> 0:00:44.000 many families lost several children to these diseases. We forget. 0:00:44.520 --> 0:00:47.640 Time blurs our memories of these common tragedies of yesteryear. 0:00:48.720 --> 0:00:51.400 I remember well, during the winter and spring of each year, 0:00:51.600 --> 0:00:55.200 hearing the whoop of protessis and movie theaters, school assemblies, 0:00:55.240 --> 0:00:58.920 and assorted gatherings. Today few have ever heard this, and 0:00:59.000 --> 0:01:03.760 those who have forget. I remember the summer outbreaks of polio, 0:01:03.960 --> 0:01:06.559 the crippled children who could no longer walk or walk 0:01:06.640 --> 0:01:10.520 with limb distorted limps. As a third and fourth year 0:01:10.600 --> 0:01:14.520 medical student, I remember answering the appeals of hospital administrators 0:01:14.520 --> 0:01:17.080 who could not find the nursing staff for special duty 0:01:17.200 --> 0:01:20.120 tending to the needs of polio patients in iron lungs. 0:01:20.840 --> 0:01:21.440 We forget. 0:01:22.680 --> 0:01:26.280 I remember the awful cases of measles my own children experienced. 0:01:27.000 --> 0:01:29.720 I remember the children with smallpox during the years my 0:01:29.760 --> 0:01:33.600 family lived in Pakistan. I remember those who lost their 0:01:33.640 --> 0:01:37.800 sight from lesions in their eyes. I remember those who died. 0:01:38.640 --> 0:01:39.280 We forget. 0:02:24.320 --> 0:02:25.840 So that was. 0:02:26.320 --> 0:02:33.720 A letter to the Immunization Action Coalition by E. J. 0:02:34.200 --> 0:02:38.320 Jean Gangarosa, who was a professor emeritus from Emory University. 0:02:38.480 --> 0:02:43.320 He wrote that letter in two thousand. Yeah, it's it 0:02:43.400 --> 0:02:47.839 is amazing. He's very right. We do forget. And those 0:02:47.880 --> 0:02:51.280 of us who have never heard it don't know, right, Yeah, 0:02:51.320 --> 0:02:55.200 we don't know what it's like. My name is Aaron. 0:02:54.960 --> 0:02:57.360 Welsh and I'm Aaron Oman Updyke. 0:02:57.480 --> 0:02:59.640 And this is this podcast will Kill. 0:02:59.480 --> 0:03:01.520 You Vaccines Today. 0:03:01.720 --> 0:03:06.880 Yes, this is the first episode of a two part 0:03:07.360 --> 0:03:12.640 series on vaccines and all about the history of vaccines, 0:03:12.919 --> 0:03:17.239 the biology of vaccines, how they work. And we are 0:03:17.280 --> 0:03:20.480 also so thrilled for this episode because we got to 0:03:20.520 --> 0:03:26.200 talk to two real life vaccine experts, doctor Gail Rogers 0:03:26.360 --> 0:03:30.840 and doctor Pedmini Shrikantaya, who are both senior program officers 0:03:30.840 --> 0:03:34.000 at the Bill and Melinda Gates Foundation. We chatted with 0:03:34.040 --> 0:03:37.640 doctor Shrikantaia and doctor Rogers about how vaccines are developed, 0:03:37.880 --> 0:03:40.720 some of the different vaccine preventable diseases that are targeted 0:03:40.800 --> 0:03:44.520 around the world, and the challenges faced in some global 0:03:44.600 --> 0:03:49.320 vaccination initiatives. We had such a great time talking with them, 0:03:49.760 --> 0:03:51.280 seriously aspirational. 0:03:51.400 --> 0:03:54.440 Yeah, they've like lived lives that we want to live someday. 0:03:55.600 --> 0:03:58.480 It was so cool and we know that you're going 0:03:58.560 --> 0:04:03.640 to love them too. So day tuned. Okay, so what 0:04:03.840 --> 0:04:06.960 are we drinking today? It's it's vaccine time. 0:04:07.360 --> 0:04:14.200 Quarantiny time, quarantiny time. We're drinking wait for it. 0:04:13.720 --> 0:04:22.240 Enders fame, finally, finally, Yes. So this quarantini is named 0:04:22.279 --> 0:04:25.960 for John Enders, who is the recipient of a Nobel 0:04:26.000 --> 0:04:30.120 Prize for his work on how on cultivating the poliovirus, 0:04:30.400 --> 0:04:33.840 which really paved the way to create polio vaccine. He 0:04:33.880 --> 0:04:37.200 also created the measles vaccine. I'm talking too much about 0:04:37.240 --> 0:04:38.839 the history. Tell me what's in the drink. 0:04:40.000 --> 0:04:44.239 It's konnac orange liqueur and lemon juice. 0:04:44.320 --> 0:04:45.440 Is basically a sidecar. 0:04:46.000 --> 0:04:50.279 Yeah, so fancy little fancy, little fun drink, and we'll 0:04:50.320 --> 0:04:53.560 have the full recipe for that quarantini as well as 0:04:53.640 --> 0:04:57.000 our non alcoholic plusy burrita on all of our social 0:04:57.000 --> 0:05:00.279 media channels as well as our website. This part okays 0:05:00.320 --> 0:05:01.880 We'll kill You dot com. 0:05:02.680 --> 0:05:06.440 Yeah, check it out, check check it out. We also 0:05:06.880 --> 0:05:10.400 really quick need to make a fun little announcement. We 0:05:10.600 --> 0:05:14.040 are working on an episode where we answer questions you 0:05:14.080 --> 0:05:18.200 send us about us, or about disease ecology or epidemiology, 0:05:18.279 --> 0:05:22.520 or podcasting or cocktail techniques or honestly whatever you can think. 0:05:22.360 --> 0:05:26.160 Of anything you want to know, So send us your 0:05:26.240 --> 0:05:30.040 questions by email to this podcast will Kill You at 0:05:30.080 --> 0:05:31.360 gmail dot com. 0:05:32.279 --> 0:05:34.680 And if you decide to send us a question that 0:05:34.760 --> 0:05:37.599 you want us to answer for this episode, please put 0:05:37.880 --> 0:05:40.680 ask the errands or something to that effect in the 0:05:40.720 --> 0:05:43.279 subject line and let us know whether you're okay with 0:05:43.360 --> 0:05:44.960 us saying your name on the episode. 0:05:45.320 --> 0:05:48.479 We can't wait to hear from you, all right, should 0:05:48.520 --> 0:05:49.920 we just jump right into it? 0:05:50.600 --> 0:05:51.400 I think we should. 0:05:51.480 --> 0:05:53.240 Okay, We'll take a quick shark break. 0:06:22.000 --> 0:06:26.960 So, vaccines are often called one of the greatest public 0:06:26.960 --> 0:06:31.480 health inventions of all time, and I agree they totally are. 0:06:31.920 --> 0:06:36.839 But it's partially because they work at two different levels. 0:06:37.800 --> 0:06:40.800 Vaccines work both on an individual level, so when you 0:06:40.880 --> 0:06:45.120 get vaccinated, you are protected against whatever infection you just 0:06:45.160 --> 0:06:48.240 got vaccinated against, which is great. Who doesn't want to 0:06:48.240 --> 0:06:53.159 be protected? But they also work at the population level, 0:06:53.760 --> 0:06:57.240 so when you get vaccinated, you're actually protecting all of 0:06:57.279 --> 0:07:01.320 those around you as well. Can pat yourself on the 0:07:01.360 --> 0:07:04.680 back for doing a public service every time you get vaccinated. 0:07:06.560 --> 0:07:11.200 So to understand exactly how vaccines can be so awesome 0:07:11.600 --> 0:07:15.000 and work on these two totally different levels, I'm going 0:07:15.080 --> 0:07:17.840 to get into some serious detail about the biology and 0:07:17.880 --> 0:07:21.040 epidemiology of how they work. And I'm going to do 0:07:21.120 --> 0:07:24.320 it so that you can a understand how awesome our 0:07:24.440 --> 0:07:29.760 immune systems are. B understand how cool it is that 0:07:29.840 --> 0:07:33.720 vaccines exist, and see be the one who explains this 0:07:33.760 --> 0:07:36.000 to Aunt Martha at Thanksgiving this year. 0:07:36.520 --> 0:07:39.200 Oh yeah, okay, excellent. 0:07:39.560 --> 0:07:39.920 All right. 0:07:40.880 --> 0:07:45.280 So, to first understand how vaccines can protect you, specifically, 0:07:45.560 --> 0:07:49.080 dear listeners, we first have to understand how our immune 0:07:49.120 --> 0:07:53.040 system works and how our bodies fight off infection. So 0:07:53.480 --> 0:07:55.960 immuneologists don't hate me. I'm going to break this down 0:07:56.000 --> 0:08:00.920 in the simplest possible way. More complicated, but these are 0:08:00.920 --> 0:08:05.720 the basics. There are two major parts to our immune system. 0:08:06.440 --> 0:08:11.240 There's a non specific which is called the innate immune response, 0:08:11.920 --> 0:08:14.280 and then there's a specific response, which is called the 0:08:14.320 --> 0:08:20.000 adaptive response. Okay, the innate immune response, it's very fast 0:08:20.120 --> 0:08:24.119 on the uptake. When you get exposed to viruses or bacteria, 0:08:24.200 --> 0:08:26.240 it can find them and start to get to work 0:08:26.520 --> 0:08:30.640 really quickly, but it's not that powerful. It doesn't last 0:08:30.680 --> 0:08:35.319 that long and it can't destroy everything. So we have 0:08:35.360 --> 0:08:38.120 a second immune response, the adaptive immune response. 0:08:38.960 --> 0:08:42.760 This is something that allows us to target very specific. 0:08:42.240 --> 0:08:46.440 Individual pathogens, but it takes some time. It's a little 0:08:46.440 --> 0:08:49.240 bit slow to get started. So what that means is 0:08:49.280 --> 0:08:52.800 that before your adaptive immune response kicks in, you usually 0:08:53.240 --> 0:08:58.920 get sick, you feel crappy, and then your adaptive immune 0:08:58.920 --> 0:09:01.720 system needs time to kick in and actually fight off 0:09:01.760 --> 0:09:04.640 that infection. But the good thing about this adaptive immune 0:09:04.679 --> 0:09:08.840 response is that it has a memory like an elephant. 0:09:09.559 --> 0:09:11.240 It never it never forgets. 0:09:12.000 --> 0:09:16.440 So anything that the adaptive immune response has responded to once, 0:09:17.320 --> 0:09:21.800 the second time it's exposed to that same virus or bacteria, 0:09:21.880 --> 0:09:25.280 it can respond much more rapidly and much more effectively. 0:09:25.920 --> 0:09:30.040 Right, Okay, So here's how it works. In four acts. 0:09:30.120 --> 0:09:31.120 We're gonna have a play. 0:09:31.559 --> 0:09:33.480 Oh my god, mine's the four parts too. 0:09:34.120 --> 0:09:36.040 Oh my god, we didn't even plan that. 0:09:36.320 --> 0:09:37.000 Oh we didn't. 0:09:38.400 --> 0:09:40.079 Okay, thrilling, Oh my goodness. 0:09:40.160 --> 0:09:45.360 Okay, so we're uh biology play first four X. 0:09:45.520 --> 0:09:46.080 Here we go. 0:09:47.200 --> 0:09:49.680 So we have three main characters. Do you have three 0:09:49.679 --> 0:09:50.600 main characters too? 0:09:51.679 --> 0:09:53.320 I have a host of characters. 0:09:53.360 --> 0:09:57.520 Okay, well, we're just simplifying it to three. We're gonna 0:09:57.559 --> 0:10:01.600 have three main characters in our immune system play the macrophages, 0:10:02.440 --> 0:10:04.959 the T cells, and the B cells. 0:10:05.280 --> 0:10:05.679 Okay. 0:10:06.000 --> 0:10:08.960 All of these three characters are types of white blood cells, 0:10:09.440 --> 0:10:11.920 and in your body you have a lot more than 0:10:12.000 --> 0:10:15.319 just these three, but these are our three main characters, 0:10:15.360 --> 0:10:17.880 and all of the rest of your white blood cells are. 0:10:17.760 --> 0:10:20.760 Going to be the ensemble. Okay, all right. 0:10:21.840 --> 0:10:22.960 Act one. 0:10:23.360 --> 0:10:29.719 You breathe, Okay, in your breath, you inhale an antigen. 0:10:30.640 --> 0:10:35.280 This might be a virus, a bacteria, a toxin, your 0:10:35.320 --> 0:10:39.319 neighbor's boogers, aerosolized poop, whatever. 0:10:39.679 --> 0:10:40.120 It's nice. 0:10:41.080 --> 0:10:42.320 Yeah, well that's life. 0:10:42.760 --> 0:10:45.840 It's a foreign substance that doesn't belong in your body, 0:10:45.880 --> 0:10:49.640 and in your body just waiting at the ready are thousands, 0:10:49.760 --> 0:10:54.920 nay millions of these white blood cells ready to jump 0:10:54.960 --> 0:11:02.000 into action. First incomes the macrophages. The macrophagers are going 0:11:02.080 --> 0:11:06.040 to see this antigen, this virus or bacteria, and they're 0:11:06.040 --> 0:11:10.840 going to eat it. They're gonna gobble it up, and 0:11:10.880 --> 0:11:13.800 they're gonna take that and take a part of it, 0:11:14.640 --> 0:11:16.480 and they're going to bring it over to their friends 0:11:16.520 --> 0:11:20.959 who enter stage left. The tea cells and the T 0:11:21.160 --> 0:11:25.560 cells walk in and they're like, hey, macro how's it going. 0:11:25.640 --> 0:11:27.360 What you got What do you have for us today? 0:11:27.600 --> 0:11:30.880 And the macrophage is like, so, I don't know exactly 0:11:30.920 --> 0:11:33.200 what this is, but I found it over there and 0:11:33.240 --> 0:11:34.600 I know it doesn't belong here. 0:11:34.920 --> 0:11:38.520 I recognize it. I'm not sure what to do with it. 0:11:38.559 --> 0:11:41.959 And the T cells are like, don't worry, we got you, 0:11:42.040 --> 0:11:42.800 act too. 0:11:43.200 --> 0:11:43.760 We got you. 0:11:46.040 --> 0:11:50.440 So the T cells they recognize that antigen. There's a 0:11:50.440 --> 0:11:53.440 whole group of these T cells and they're like, we 0:11:53.480 --> 0:11:57.400 can do two different things. Some of these tea cells 0:11:57.679 --> 0:12:01.240 they're a little wacky, they're a little wild. Okay, they're 0:12:01.240 --> 0:12:04.240 called the cytotoxic tea cells. They probably have like a 0:12:04.280 --> 0:12:09.520 mohawk and a motorcycle, sweet. They recognize that antigen, they're like, 0:12:09.840 --> 0:12:11.560 I know, I know how to take care of this, 0:12:11.600 --> 0:12:14.920 don't worry. So they're gonna exit and they're gonna go 0:12:15.000 --> 0:12:20.600 start replicating like wildfire, and they're gonna go out and 0:12:20.720 --> 0:12:24.960 just find anything that has that same antigen, any virus 0:12:25.000 --> 0:12:27.480 that looks the same, any bacteria that looks the same 0:12:27.520 --> 0:12:30.439 as that antigen, and they're gonna go out and kill it. 0:12:30.480 --> 0:12:33.319 They're just gonna start murdering things throughout your body. 0:12:33.360 --> 0:12:36.400 Okay, okay, shoot first, ask questions later. 0:12:36.559 --> 0:12:37.079 Exactly. 0:12:37.559 --> 0:12:41.040 So those are the cidotoxic mohawk tea cells. The other 0:12:41.120 --> 0:12:44.040 T cells they've got like bangs in a short bob. 0:12:44.679 --> 0:12:49.920 They're the helper T cells. They're a lot calmer. They're 0:12:49.960 --> 0:12:54.000 gonna take this antigen and swing their way over to 0:12:54.080 --> 0:12:58.040 their friends who hang out at the lymph node bar, 0:12:59.080 --> 0:13:02.920 the B cells. And as they walk into the lymph nodebar, 0:13:03.000 --> 0:13:06.440 they call out amongst the thousands of B cells just 0:13:06.480 --> 0:13:11.880 hanging out and they're like, hey, hi, everybody, does anyone 0:13:11.960 --> 0:13:16.320 recognize this anigen? Mcriface just dropped it off. Do you 0:13:16.360 --> 0:13:18.199 guys know what to do with it? This is kind 0:13:18.240 --> 0:13:22.920 of your thing? And in through the swinging what do 0:13:23.000 --> 0:13:28.199 you call those old timey western doors, swinging doors, swingy 0:13:28.240 --> 0:13:32.880 Western doors. You hear the clink saloon doors, saloon doors. 0:13:32.920 --> 0:13:33.400 There you go. 0:13:33.920 --> 0:13:37.400 You hear the clink clink of spurs and in walks 0:13:37.920 --> 0:13:42.319 wearing a ten gallon hat a B cell and he says, 0:13:43.000 --> 0:13:47.840 I sure do, I sure do recognize that antigen. And 0:13:47.880 --> 0:13:53.120 then they get to work actually immunity. So ten gallon 0:13:53.120 --> 0:13:56.600 hat B cell, he knows what to do. He starts 0:13:56.679 --> 0:14:01.120 replicating and replicating, making more and more copies of himself, 0:14:01.160 --> 0:14:08.880 and inside he's making antibodies. These antibodies are super specific. 0:14:09.280 --> 0:14:12.720 They're going to target just that one antigen that the 0:14:12.760 --> 0:14:16.040 T cell brought over. And these B cells are making 0:14:16.440 --> 0:14:19.240 millions of these antibodies, and what they do is they 0:14:19.560 --> 0:14:23.240 throw them out into your bloodstream. They travel throughout your 0:14:23.280 --> 0:14:28.160 whole body, and they find and attached to that anigen 0:14:28.520 --> 0:14:31.560 anywhere that they find it, whether it's in your cells 0:14:31.840 --> 0:14:35.200 that have been infected, whether it's on the bacteria or 0:14:35.240 --> 0:14:37.880 on the outside of a virus. Anything that has this 0:14:38.000 --> 0:14:41.280 specific anigen is going to get an antibody attached to it. 0:14:41.280 --> 0:14:45.040 It's kind of like a flag that you put on buildings. 0:14:45.280 --> 0:14:47.120 When you say this one's going to get demolished, and 0:14:47.160 --> 0:14:50.000 this one's going to get demolished, that's what an antibody is. 0:14:50.480 --> 0:14:53.160 So these antibodies go out and mark all of these 0:14:53.200 --> 0:14:56.560 cells so that the ensemble, the rest of the cast, 0:14:56.720 --> 0:14:59.320 the rest of your white blood cells can recognize it. 0:15:00.120 --> 0:15:02.760 They can come in and clean up the mess. They 0:15:02.880 --> 0:15:07.520 take soldiers exactly, So they come in and destroy that infection. 0:15:08.160 --> 0:15:13.280 Okay, So can I just review absolutely? Okay. So the 0:15:13.320 --> 0:15:17.040 macrifhage picks something up weird and then they bring it 0:15:17.080 --> 0:15:21.640 over and they're like, okay, everyone, T cells, B cells, 0:15:22.480 --> 0:15:23.040 what is this? 0:15:23.280 --> 0:15:23.800 Mm hmmm. 0:15:24.000 --> 0:15:27.600 So the T cells, the killer ones, they go and 0:15:27.640 --> 0:15:31.240 they just kill anything that remotely resembles that antigen. 0:15:30.920 --> 0:15:33.320 Anything that specifically resembles that antigen. 0:15:33.840 --> 0:15:38.920 Okay, specifically resembles that antigen. What does that mean? Specifically resembles? 0:15:38.960 --> 0:15:42.080 It means anything that is that exact same anagen. So 0:15:42.120 --> 0:15:44.080 it's not going to go out and just kill anything 0:15:44.120 --> 0:15:47.400 that looks similar to it. It'll just okay, that exact antigen. 0:15:47.760 --> 0:15:51.440 Okay. And then the helper T cells they go and 0:15:51.480 --> 0:15:54.200 find the B cells and say, hey, this is what 0:15:54.200 --> 0:15:57.360 we're looking for. Can you go and tag everything exactly? 0:15:57.400 --> 0:16:00.160 So then that makes the killer T cells. 0:16:00.320 --> 0:16:02.280 Easier, absolutely yeah. 0:16:02.560 --> 0:16:04.360 And it also brings in the rest of the white 0:16:04.360 --> 0:16:06.400 blood cells so that it's not just the T cells 0:16:06.400 --> 0:16:12.960 out there killing things. Okay, Act four Memory. So once 0:16:13.000 --> 0:16:15.640 your body has done all this work and cleared the infection, 0:16:15.840 --> 0:16:19.160 it's not done. Old ten gallon hat B cell and 0:16:19.240 --> 0:16:23.720 a few of those wild cytotoxic mohawk T cells they're 0:16:23.760 --> 0:16:28.400 going to develop into memory cells. These cells hang out 0:16:28.640 --> 0:16:31.960 and persist. They no longer run around making antibodies or 0:16:32.040 --> 0:16:36.400 killing cells. They're going to go backstage and wait until 0:16:36.400 --> 0:16:38.840 it's their time again. Maybe they'll play cards, they'll bide 0:16:38.880 --> 0:16:44.040 their time, and if that same antigen ever shows their 0:16:44.080 --> 0:16:48.040 face again, these B cells and T cells, the memory 0:16:48.120 --> 0:16:51.600 cells will be able to jump right back into action. 0:16:51.880 --> 0:16:54.480 They won't have to go through the whole rigamarole of 0:16:54.600 --> 0:16:57.560 acts one, two, and three. They'll just be able to 0:16:57.720 --> 0:17:00.640 use the antibodies they've already have in the mem resells 0:17:01.560 --> 0:17:05.720 to make more copies and identify and target that anagen 0:17:05.840 --> 0:17:10.600 and quash the infection before it ever takes hold. So 0:17:10.800 --> 0:17:16.080 this is the principle that vaccines exploit. They expose you 0:17:16.160 --> 0:17:19.480 to an anigen, which is a virus or a bacteria 0:17:19.640 --> 0:17:23.200 or part of a virus or bacteria, and that triggers 0:17:23.240 --> 0:17:27.960 your immune system to develop this memory response, so that 0:17:28.080 --> 0:17:31.159 if you're ever exposed to that virus or bacteria in 0:17:31.240 --> 0:17:34.280 real life, you've already got a response ready to go. 0:17:34.359 --> 0:17:36.320 You don't have to take the time to build that 0:17:36.400 --> 0:17:37.240 immune response. 0:17:37.960 --> 0:17:42.880 And so the difference between that first exposure and then 0:17:43.200 --> 0:17:46.560 seeing that same pathogen again is a state of disease 0:17:46.680 --> 0:17:48.639 and then a state of rapid immune response and no 0:17:48.760 --> 0:17:52.760 disease exactly, and then a vaccine just bypasses that whole disease. 0:17:52.960 --> 0:17:57.160 You don't have to actually endure the disease symptoms exactly. 0:17:57.240 --> 0:18:01.800 So if you imagine that you're immune cells in a 0:18:01.880 --> 0:18:04.960 lot of cases, if they're dealing with a live virus, 0:18:05.000 --> 0:18:08.879 a full on, fully loaded measles virus, it's not like 0:18:08.920 --> 0:18:11.840 they're just dealing with something passive. That virus has come 0:18:11.880 --> 0:18:16.359 in guns ablazing, it's replicating, it's going full force, while 0:18:16.480 --> 0:18:19.480 your immune cells might be kind of like tripping over 0:18:19.520 --> 0:18:22.280 their lines and getting things wrong and trying. 0:18:22.080 --> 0:18:23.639 To figure out what to do about it. 0:18:24.119 --> 0:18:28.439 Right, So, an immunization is kind of like a dress 0:18:28.480 --> 0:18:29.879 rehearsal for the play. 0:18:30.160 --> 0:18:30.720 It's real. 0:18:30.960 --> 0:18:33.840 There's people in the audience still, and you're going to 0:18:33.920 --> 0:18:36.959 develop the exact same response at the end of it. 0:18:37.320 --> 0:18:40.920 But you don't have a live virus trying to kill 0:18:40.960 --> 0:18:44.960 you while you develop this immune response the very first time. 0:18:45.720 --> 0:18:52.160 Mm hmmmm cool yeah, cool, it's fantastic. I mean, vaccines 0:18:52.160 --> 0:18:52.919 are the best. 0:18:52.680 --> 0:18:53.320 Are the best. 0:18:53.840 --> 0:18:58.040 So that's how vaccination can protect you as an individual. 0:18:58.920 --> 0:19:02.160 How does it protect an entire population. This is something 0:19:02.160 --> 0:19:07.639 we've touched on before, but it's called herd immunity, and 0:19:07.680 --> 0:19:15.400 it goes something like this. Every infectious agent bacteria, virus, fungi, whatever, 0:19:16.440 --> 0:19:20.000 in order to survive, it has to spread from person 0:19:20.240 --> 0:19:20.800 to person. 0:19:21.040 --> 0:19:22.719 That's how they reproduce. 0:19:23.720 --> 0:19:25.840 And in order to do so, in order to spread 0:19:25.880 --> 0:19:29.800 from person to person, there have to be susceptible people 0:19:30.520 --> 0:19:36.120 in the population for that virus or bacteria to get into. 0:19:36.560 --> 0:19:40.520 So if a population has a high level of vaccination, 0:19:40.680 --> 0:19:43.840 let's say like ninety seven percent of one hundred people 0:19:44.400 --> 0:19:48.600 are vaccinated, that means that those ninety seven people have 0:19:48.760 --> 0:19:54.040 developed this immune response already. They're already protected. So if 0:19:54.080 --> 0:19:56.959 you happen to drop an infected person in the middle 0:19:57.000 --> 0:20:01.720 of that population. The chances that that infected person would 0:20:01.800 --> 0:20:06.840 run into somebody who's still susceptible to that disease are really, 0:20:06.880 --> 0:20:10.960 really low. So you'd have that one infected person who 0:20:11.000 --> 0:20:14.720 will get sick and then hopefully they'll recover, or else 0:20:14.760 --> 0:20:18.520 they'll die from their infection, and then that's it. Nobody 0:20:18.560 --> 0:20:21.800 else gets sick because that sick person didn't run into 0:20:21.840 --> 0:20:26.679 anyone who was susceptible to that disease. But if you 0:20:26.800 --> 0:20:30.160 imagine that maybe only fifty percent of people are vaccinated, 0:20:30.520 --> 0:20:33.760 then only fifty percent of people are immune and the 0:20:33.800 --> 0:20:38.040 other fifty are susceptible, and you dropped an infected individual 0:20:38.040 --> 0:20:40.720 in the middle of that population, there's a pretty good 0:20:40.800 --> 0:20:43.560 chance that that infected person will run into somebody who 0:20:43.640 --> 0:20:47.600 happens to be susceptible, and maybe they cough or they 0:20:47.600 --> 0:20:50.280 shake their hand or lick their face, and now you 0:20:50.280 --> 0:20:54.200 have two infected people. And then that second infected person, 0:20:54.720 --> 0:20:58.120 they have a pretty good shot, like forty nine more 0:20:58.160 --> 0:21:02.119 people that they might run into another susceptible individual and 0:21:02.200 --> 0:21:07.560 lick their face, and now you have three infected individuals, right, 0:21:07.760 --> 0:21:09.760 and so on and so on. So this is the 0:21:09.800 --> 0:21:14.679 principle behind herd immunity. If the entire herd, the entire population, 0:21:15.440 --> 0:21:18.720 or enough of it is immune to infection, either because 0:21:19.240 --> 0:21:22.800 they've already been exposed and recovered from the disease or 0:21:23.400 --> 0:21:27.480 they were vaccinated and they developed immunity, then the infection 0:21:27.680 --> 0:21:28.320 can't spread. 0:21:29.280 --> 0:21:29.480 Right. 0:21:29.880 --> 0:21:33.479 So the more people that are immunized against something or 0:21:33.920 --> 0:21:38.120 immune to something by whatever, means the less chance that 0:21:38.320 --> 0:21:41.320 a pathogen has of establishing in a population or being 0:21:41.320 --> 0:21:42.480 transmitted exactly. 0:21:42.520 --> 0:21:46.480 So by getting vaccinated, you are protecting yourself from getting 0:21:46.520 --> 0:21:49.200 that infection, but you're also protecting that tiny baby on 0:21:49.240 --> 0:21:52.360 the train who's too young to get vaccinated, your grandma 0:21:52.440 --> 0:21:57.479 who's frail and immunocompromised, whoever. You're protecting literally everyone around 0:21:57.520 --> 0:22:03.320 you when you get vaccinated. So that's how vaccines work. 0:22:03.760 --> 0:22:07.600 They're pretty dang cool. Yeah, I love them, big fan, 0:22:07.960 --> 0:22:14.560 me too, major if you can't tell already. So, there 0:22:14.600 --> 0:22:17.240 are a lot of different types of vaccines, and we're 0:22:17.240 --> 0:22:20.680 going to talk a little bit about the differences between them. 0:22:20.800 --> 0:22:24.720 Not a full on immunology lecture, but just a quick rundown. 0:22:25.040 --> 0:22:26.840 But I do want to say at the very top 0:22:26.880 --> 0:22:31.720 of this that all vaccines that are used are extremely safe. 0:22:31.760 --> 0:22:37.320 They're extensively tested and very highly regulated, and all the 0:22:37.359 --> 0:22:40.359 different types of vaccines that we have are very effective. 0:22:41.280 --> 0:22:43.560 And part of the reason that we have different types 0:22:43.600 --> 0:22:48.320 of vaccines is because different viruses and bacteria behave differently 0:22:48.400 --> 0:22:50.040 and so we have to come up with different types 0:22:50.080 --> 0:22:51.120 of vaccines. 0:22:50.680 --> 0:22:52.639 To target those specific pathogens. 0:22:53.400 --> 0:22:57.960 So some vaccines, for example, the MMR vaccine that's measles, 0:22:58.080 --> 0:23:01.840 mumps and rubella, which you talked about before, and also verisicella, 0:23:01.880 --> 0:23:05.080 which is chicken pox. These are made from what we 0:23:05.119 --> 0:23:10.120 call live attenuated viruses, so that means the vaccine itself 0:23:10.160 --> 0:23:13.199 has a live virus in it, but that virus has 0:23:13.240 --> 0:23:14.640 been modified. 0:23:14.520 --> 0:23:16.520 So that it's super super weak. 0:23:16.840 --> 0:23:20.520 It's not a strong, virulent virus that actually makes you 0:23:20.560 --> 0:23:27.280 get sick. It's a weak, little infantile virus. Through this 0:23:27.400 --> 0:23:31.000 type of vaccine elicits a really good immune response because 0:23:31.040 --> 0:23:33.439 it's just like getting a real infection in that you 0:23:33.520 --> 0:23:38.440 have virus replicating in your body, but because it's such 0:23:38.440 --> 0:23:41.960 a weak virus, you don't get sick from it. However, 0:23:42.040 --> 0:23:45.160 it does mean that some people who are immunal compromised, 0:23:45.320 --> 0:23:48.120 who have very weak immune systems might not be able 0:23:48.160 --> 0:23:51.119 to get these live virus vaccines because their immune system 0:23:51.240 --> 0:23:53.560 might not be strong enough to fight off even. 0:23:53.440 --> 0:23:54.880 A very weak virus. 0:23:55.680 --> 0:24:01.720 Gotcha, Okay, we also have whole killed vasvaccines. So these 0:24:01.760 --> 0:24:04.280 are vaccines that are a whole entire virus, so all 0:24:04.280 --> 0:24:07.240 of the different parts of the virus, but we kill 0:24:07.280 --> 0:24:09.439 the virus before we make the vaccine out of it. 0:24:09.520 --> 0:24:12.520 So that's the inactivated poliovirus, the one that is an 0:24:12.560 --> 0:24:16.320 injection or the influenza vaccine. 0:24:16.480 --> 0:24:18.879 And so are there also killed bacteria vaccine? 0:24:19.080 --> 0:24:22.000 Are Yeah, So there's a killed bacteria vaccine for typhoid 0:24:22.000 --> 0:24:24.360 and there's also a live vaccine for typhoid. 0:24:24.840 --> 0:24:26.120 Hey, there's both. 0:24:26.160 --> 0:24:26.440 Cool. 0:24:28.320 --> 0:24:31.760 So these whole killed vaccines, you still develop a really 0:24:31.800 --> 0:24:34.560 strong immune response, but you might need to get more 0:24:34.600 --> 0:24:37.119 boosters with this type of vaccine because it might not 0:24:37.200 --> 0:24:39.600 be quite as strong of a response as you get 0:24:39.640 --> 0:24:44.320 from a live vaccine. But people who are immuno compromised 0:24:44.480 --> 0:24:47.280 can still get these killed virus vaccines because there's no 0:24:47.440 --> 0:24:50.080 live virus in these vaccines that's replicating. 0:24:50.840 --> 0:24:55.480 So going back to the flu vaccine, yes, this means. 0:24:55.440 --> 0:24:56.560 This means. 0:24:57.760 --> 0:25:00.840 That you cannot get the flu from the fl vaccine. 0:25:01.480 --> 0:25:06.359 Correct, absolutely not ever so more, can you pass on 0:25:07.000 --> 0:25:11.320 the flu to someone if you have gotten the flu shot? 0:25:11.600 --> 0:25:13.560 Exactly, it's not possible. 0:25:13.640 --> 0:25:19.200 It's a killed dead virus. Okay. Sometimes you might get 0:25:19.240 --> 0:25:23.440 a slight fever or muscle aches, especially in the arm 0:25:23.480 --> 0:25:25.360