WEBVTT - Re-Release: Ep 26 Vaccines Part 1: Let's hear it for Maurice 0:00:02.240 --> 0:00:04.840 Hello to listeners old and new. 0:00:05.600 --> 0:00:09.399 We are trying something new this week and next we 0:00:09.440 --> 0:00:12.320 are going to be re releasing two of our favorite 0:00:12.440 --> 0:00:15.800 past episodes, Vaccines Part one and two. 0:00:16.440 --> 0:00:20.320 These are two episodes that we are really, really proud of. 0:00:20.840 --> 0:00:24.279 We've referenced them both countless times since we release them, 0:00:24.680 --> 0:00:27.720 and our audience has grown a lot since our second season, 0:00:28.000 --> 0:00:30.560 so there's probably a fair amount of you that haven't 0:00:30.560 --> 0:00:33.680 ever heard these And as we've. 0:00:33.440 --> 0:00:35.839 Seen in the past two years, as this pandemic has 0:00:35.920 --> 0:00:40.480 reached on, the importance of vaccines is still so apparent. 0:00:40.520 --> 0:00:44.000 And misinformation and disinformation abounds. 0:00:44.760 --> 0:00:47.600 We'll be back in two weeks with fresh new content 0:00:47.640 --> 0:00:50.320 for your ears, but for now, we hope you enjoy 0:00:50.440 --> 0:00:52.560 for the second time Vaccines. 0:00:55.520 --> 0:00:58.440 I am one of the increasingly rare old timers who 0:00:58.480 --> 0:01:01.680 lived during the pre vaccine nation era. I am the 0:01:01.720 --> 0:01:04.959 second to the last of thirteen siblings, five of whom 0:01:05.040 --> 0:01:09.280 died of vaccine preventable diseases in infancy, born to poor 0:01:09.319 --> 0:01:12.280 immigrant parents. I remember well my mother's account of the 0:01:12.319 --> 0:01:17.920 causes of their deaths, three from protessis and two from measles. 0:01:18.600 --> 0:01:21.280 Even after many years had passed, she spoke of the 0:01:21.319 --> 0:01:23.640 death of her angels with a great deal of emotion. 0:01:24.200 --> 0:01:29.920 Imagine losing not one, two, three, or four, but five babies. 0:01:30.680 --> 0:01:34.080 It was common in the pre vaccine era. Like our family, 0:01:34.200 --> 0:01:38.240 many families lost several children to these diseases. We forget. 0:01:38.959 --> 0:01:42.080 Time blurs our memories of these common tragedies of yesteryear. 0:01:43.160 --> 0:01:45.839 I remember well during the winter and spring of each year, 0:01:46.040 --> 0:01:49.640 hearing the whoop of protessis and movie theaters, school assemblies, 0:01:49.640 --> 0:01:53.320 and assorted gatherings. Today few have ever heard this, and 0:01:53.400 --> 0:01:58.200 those who have forget. I remember the summer outbreaks of polio, 0:01:58.400 --> 0:02:00.960 the crippled children who could no longer walk or walk 0:02:01.040 --> 0:02:04.960 with limb distorted limps. As the third and fourth year 0:02:05.040 --> 0:02:08.920 medical student, I remember answering the appeals of hospital administrators 0:02:08.960 --> 0:02:11.480 who could not find the nursing staff for special duty 0:02:11.639 --> 0:02:14.520 tending to the needs of polio patients in iron lungs. 0:02:15.240 --> 0:02:19.320 We forget. I remember the awful cases of measles my 0:02:19.360 --> 0:02:23.480 own children experienced. I remember the children with smallpox during 0:02:23.520 --> 0:02:27.239 the years my family lived in Pakistan. I remember those 0:02:27.320 --> 0:02:30.880 who lost their sight from lesions in their eyes. I 0:02:30.960 --> 0:03:21.400 remember those who died. We forget. So that was a 0:03:21.520 --> 0:03:29.800 letter to the Immunization Action Coalition by E. J. Jean Gangarosa, 0:03:29.919 --> 0:03:33.320 who was a professor emeritus from Emory University. He wrote 0:03:33.320 --> 0:03:38.400 that letter in two thousand. Yeah, it's it is amazing. 0:03:38.480 --> 0:03:42.560 He's very right. We do forget and those of us 0:03:42.600 --> 0:03:45.840 who have never heard it don't know, right, Yeah, we 0:03:45.840 --> 0:03:49.960 don't know what it's like. My name is Aaron Welsh 0:03:50.000 --> 0:03:53.360 and I'm Aaron Oman Updyke and this is this podcast 0:03:53.440 --> 0:03:59.240 will Kill You Vaccines Today. Yes, this is the first 0:03:59.320 --> 0:04:04.960 episode of a two part series on vaccines and all 0:04:05.000 --> 0:04:10.080 about the history of vaccines, the biology of vaccines, how 0:04:10.120 --> 0:04:13.360 they work. And we are also so thrilled for this 0:04:13.440 --> 0:04:16.680 episode because we got to talk to two real life 0:04:16.839 --> 0:04:23.080 vaccine experts, who doctor Gail Rogers and doctor Pedmini Shrikantaya, 0:04:23.400 --> 0:04:25.760 who are both senior program officers at the Bill and 0:04:25.800 --> 0:04:29.919 Melinda Gates Foundation. We chatted with doctor Shrikantaia and doctor 0:04:30.000 --> 0:04:32.960 Rogers about how vaccines are developed, some of the different 0:04:33.000 --> 0:04:36.520 vaccine preventable diseases that are targeted around the world, and 0:04:36.680 --> 0:04:41.440 the challenges faced in some global vaccination initiatives. We had 0:04:41.720 --> 0:04:45.680 such a great time talking with them, seriously aspirational. 0:04:45.839 --> 0:04:48.880 Yeah, they've like lived lives that we want to live someday. 0:04:50.040 --> 0:04:52.920 It was so cool and we know that you're going 0:04:53.000 --> 0:04:58.080 to love them too, so stay tuned. Okay, so what 0:04:58.240 --> 0:05:02.680 are we drinking today? It's it's vaccine time, quarantiny time. 0:05:03.200 --> 0:05:14.000 It's quarantiny time. We're drinking wait for it, Enders fame, finally, finally, Yes. 0:05:14.279 --> 0:05:19.159 So this quarantini is named for John Enders, who is 0:05:19.200 --> 0:05:21.720 the recipient of a Nobel Prize for his work on 0:05:22.440 --> 0:05:26.320 how on cultivating the poliovirus, which really paved the way 0:05:26.360 --> 0:05:30.200 to create polio vaccine. He also created the measles vaccine. 0:05:30.600 --> 0:05:32.760 I'm talking too much about the history. Tell me what's 0:05:32.760 --> 0:05:33.240 in the drink. 0:05:34.400 --> 0:05:38.640 It's kgnac, orange liqueur and lemon juice. 0:05:38.760 --> 0:05:39.839 Is basically a sidecar. 0:05:40.440 --> 0:05:44.719 Yeah, so fancy, little, fancy, little fun drink. And we'll 0:05:44.720 --> 0:05:47.960 have the full recipe for that quarantini as well as 0:05:48.040 --> 0:05:51.360 our non alcoholic plusy burrita on all of our social 0:05:51.440 --> 0:05:54.840 media channels as well as our website. This podcast will 0:05:54.880 --> 0:05:56.160 kill you dot com. 0:05:57.120 --> 0:06:00.799 Yeah, check it out to check it out. We also 0:06:01.320 --> 0:06:04.839 really quick need to make a fun little announcement. We 0:06:05.040 --> 0:06:08.440 are working on an episode where we answer questions you 0:06:08.520 --> 0:06:12.640 send us about us or about disease ecology or epidemiology, 0:06:12.720 --> 0:06:16.520 or podcasting or cocktail techniques or honestly whatever you can 0:06:16.560 --> 0:06:16.960 think of. 0:06:17.160 --> 0:06:21.200 Anything you want to know, So send us your questions 0:06:21.240 --> 0:06:25.000 by email to this podcast will kill You at gmail 0:06:25.080 --> 0:06:25.720 dot com. 0:06:26.680 --> 0:06:29.120 And if you decide to send us a question that 0:06:29.160 --> 0:06:32.039 you want us to answer for this episode, please put 0:06:32.320 --> 0:06:35.120 ask the errands or something to that effect in the 0:06:35.160 --> 0:06:37.720 subject line and let us know whether you're okay with 0:06:37.800 --> 0:06:40.400 us saying your name on the episode. We can't wait 0:06:40.440 --> 0:06:43.559 to hear from you, all right, should we just jump 0:06:43.640 --> 0:06:46.640 right into it? I think we should. Okay, we'll take 0:06:46.680 --> 0:06:47.680 a quick shark break. 0:07:16.400 --> 0:07:21.360 So vaccines are often called one of the greatest public 0:07:21.400 --> 0:07:25.920 health inventions of all time, and I agree they totally are. 0:07:26.320 --> 0:07:31.280 But it's partially because they work at two different levels. 0:07:32.240 --> 0:07:35.240 Vaccines work both on an individual level, so when you 0:07:35.320 --> 0:07:39.560 get vaccinated, you are protected against whatever infection you just 0:07:39.560 --> 0:07:41.840 got vaccinated against, which is great. 0:07:42.000 --> 0:07:43.200 Who doesn't want to be protected? 0:07:44.240 --> 0:07:48.560 But they also work at the population level, so when 0:07:48.600 --> 0:07:52.640 you get vaccinated, you're actually protecting all of those around 0:07:52.720 --> 0:07:55.760 you as well. So you can pat yourself on the 0:07:55.800 --> 0:07:59.120 back for doing a public service every time you get vaccinated. 0:08:00.960 --> 0:08:05.640 So to understand exactly how vaccines can be so awesome 0:08:06.040 --> 0:08:09.440 and work on these two totally different levels, I'm going 0:08:09.480 --> 0:08:12.240 to get into some serious detail about the biology and 0:08:12.280 --> 0:08:15.480 epidemiology of how they work. And I'm going to do 0:08:15.560 --> 0:08:18.760 it so that you can a understand how awesome our 0:08:18.880 --> 0:08:24.160 immune systems are. B understand how cool it is that 0:08:24.280 --> 0:08:28.120 vaccines exist, and see be the one who explains this 0:08:28.200 --> 0:08:30.400 to Aunt Martha at Thanksgiving this year. 0:08:30.960 --> 0:08:34.319 Oh yeah, okay, excellent. All right. 0:08:35.320 --> 0:08:39.720 So to first understand how vaccines can protect you specifically, 0:08:40.000 --> 0:08:43.520 dear listeners, we first have to understand how our immune 0:08:43.520 --> 0:08:47.480 system works and how our bodies fight off infection. So 0:08:47.920 --> 0:08:50.400 immuneologists don't hate me. I'm going to break this down 0:08:50.440 --> 0:08:55.360 in the simplest possible way. More complicated, but these are 0:08:55.360 --> 0:09:00.240 the basics. There are two major parts to our immune system. 0:09:00.880 --> 0:09:05.680 There's a non specific which is called the innate immune response, 0:09:06.360 --> 0:09:08.680 and then there's a specific response, which is called the 0:09:08.760 --> 0:09:14.439 adaptive response. Okay, the innate immune response, it's very fast 0:09:14.559 --> 0:09:18.559 on the uptake. When you get exposed to viruses or bacteria, 0:09:18.640 --> 0:09:20.680 it can find them and start to get to work 0:09:20.960 --> 0:09:25.080 really quickly, but it's not that powerful. It doesn't last 0:09:25.120 --> 0:09:29.760 that long and it can't destroy everything. So we have 0:09:29.800 --> 0:09:33.680 a second immune response, the adaptive immune response. This is 0:09:33.720 --> 0:09:37.960 something that allows us to target very specific individual pathogens, 0:09:38.640 --> 0:09:41.400 but it takes some time. It's a little bit slow 0:09:41.520 --> 0:09:44.360 to get started. So what that means is that before 0:09:44.400 --> 0:09:48.360 your adaptive immune response kicks in, you usually get sick, 0:09:49.160 --> 0:09:53.880 you feel crappy, and then your adaptive immune system needs 0:09:53.960 --> 0:09:56.800 time to kick in and actually fight off that infection. 0:09:56.920 --> 0:10:00.280 But the good thing about this adaptive immune response is 0:10:00.320 --> 0:10:03.200 that it has a memory like an elephant. 0:10:04.000 --> 0:10:05.680 It never it never forgets. 0:10:06.440 --> 0:10:10.880 So anything that the adaptive immune response has responded to once, 0:10:11.760 --> 0:10:16.199 the second time it's exposed to that same virus or bacteria, 0:10:16.320 --> 0:10:19.720 it can respond much more rapidly and much more effectively. 0:10:20.320 --> 0:10:22.880 Right, Okay, so here's how it works. 0:10:23.520 --> 0:10:25.560 In four acts. We're gonna have a play. 0:10:25.960 --> 0:10:28.719 Oh my god, mine's at the four parts too. Oh 0:10:28.720 --> 0:10:31.440 my god, we didn't even plan that. Oh we didn't. 0:10:32.760 --> 0:10:34.440 That's thrilling. Oh my goodness. 0:10:34.600 --> 0:10:39.880 Okay, so we're uh biology play first four X. 0:10:39.960 --> 0:10:40.520 Here we go. 0:10:41.640 --> 0:10:44.040 So we have three main characters. Do you have three 0:10:44.120 --> 0:10:45.000 main characters too? 0:10:46.080 --> 0:10:47.720 I have a host of characters. 0:10:47.760 --> 0:10:51.960 Okay, Well, we're just simplifying it to three. We're gonna 0:10:52.000 --> 0:10:56.040 have three main characters in our immune system play the macrophages, 0:10:56.880 --> 0:10:59.200 the T cells, and the B cells. 0:10:59.640 --> 0:11:01.280 Okay, all of these three. 0:11:01.200 --> 0:11:04.679 Characters are types of white blood cells, and in your 0:11:04.720 --> 0:11:07.120 body you have a lot more than just these three, 0:11:07.920 --> 0:11:10.320 but these are our three main characters, and all of 0:11:10.360 --> 0:11:12.439 the rest of your white blood cells are going to 0:11:12.480 --> 0:11:13.360 be the ensemble. 0:11:14.000 --> 0:11:16.760 Okay, all right, Act one. 0:11:17.760 --> 0:11:24.160 You breathe, Okay, in your breath, you inhale an antigen. 0:11:25.040 --> 0:11:29.719 This might be a virus, a bacteria, a toxin, your 0:11:29.720 --> 0:11:33.800 neighbor's boogers, aerosolized poop, whatever. 0:11:34.080 --> 0:11:36.760 It's nice. Yeah, well that's life. 0:11:37.200 --> 0:11:40.280 It's a foreign substance that doesn't belong in your body, 0:11:40.320 --> 0:11:44.040 and in your body, just waiting at the ready are thousands, 0:11:44.200 --> 0:11:49.360 nay millions of these white blood cells ready to jump 0:11:49.400 --> 0:11:56.440 into action. First incomes the macrophages. The macrophages are going 0:11:56.480 --> 0:12:00.440 to see this antigen, this virus or bacteria, and they're 0:12:00.480 --> 0:12:03.760 going to eat it. They're going to gobble it up, 0:12:05.200 --> 0:12:07.840 and they're going to take that and take a part 0:12:07.920 --> 0:12:10.400 of it, and they're going to bring it over to 0:12:10.440 --> 0:12:12.560 their friends who enter stage left. 0:12:13.200 --> 0:12:16.680 The tea cells, and the tea cells walk in and 0:12:16.679 --> 0:12:20.560 they're like, hey, macro, how's it going. What you got? 0:12:20.559 --> 0:12:21.800 What do you have for us today? 0:12:22.000 --> 0:12:25.320 And the mcrofage is like, so, I don't know exactly 0:12:25.360 --> 0:12:27.640 what this is, but I found it over there and 0:12:27.679 --> 0:12:31.800 I know it doesn't belong here. I recognize it. I'm 0:12:31.880 --> 0:12:33.240 not sure what to do with it. And the T 0:12:33.400 --> 0:12:37.040 cells are like, don't worry, we got you, act too, 0:12:37.640 --> 0:12:43.880 we got you. So the T cells they recognize that 0:12:44.040 --> 0:12:46.240 an egen. There's a whole group of these tea cells 0:12:47.000 --> 0:12:50.360 and they're like, we can do two different things. Some 0:12:50.440 --> 0:12:53.559 of these tea cells they're a little wacky, they're a 0:12:53.600 --> 0:12:57.800 little wild. Okay, they're called this cytotoxic tea cells. They 0:12:57.840 --> 0:13:00.480 probably have like a mohawk and a motor cycle. 0:13:01.120 --> 0:13:03.200 Sweet. They recognize that antigen. 0:13:03.480 --> 0:13:05.720 They're like, I know, I know how to take care 0:13:05.760 --> 0:13:05.960 of this. 0:13:06.040 --> 0:13:06.640 Don't worry. 0:13:07.040 --> 0:13:10.520 So they're gonna exit and they're gonna go start replicating 0:13:11.120 --> 0:13:15.760 like wildfire, and they're gonna go out and just find 0:13:16.360 --> 0:13:19.839 anything that has that same antigen, any virus that looks 0:13:19.840 --> 0:13:22.840 the same, any bacteria that looks the same as that antigen, 0:13:23.240 --> 0:13:25.240 and they're gonna go out and kill it. They're just 0:13:25.280 --> 0:13:27.760 gonna start murdering things throughout your body. 0:13:27.800 --> 0:13:31.520 Okay, okay, shoot first, ask questions later. Exactly. 0:13:31.960 --> 0:13:35.439 So those are decided tooxic mohawk tea cells. The other 0:13:35.520 --> 0:13:38.439 T cells they've got like bangs in a short bob. 0:13:39.120 --> 0:13:44.360 They're the helper T cells. They're a lot calmer. They're 0:13:44.360 --> 0:13:48.440 gonna take this antigen and swing their way over to 0:13:48.520 --> 0:13:52.440 their friends who hang out at the lymph node bar, 0:13:53.520 --> 0:13:56.959 the B cells. And as they walk into the lymph 0:13:56.960 --> 0:14:00.200 node bar, they call out amongst the thousands of B 0:14:00.320 --> 0:14:04.760 cells just hanging out, and they're like, hey, hi, everybody, 0:14:05.720 --> 0:14:07.920 does anyone recognize this anigen? 0:14:08.200 --> 0:14:11.480 Mcriphace just dropped it off. Do you guys know what 0:14:11.520 --> 0:14:13.240 to do with it? This is kind of your thing. 0:14:14.120 --> 0:14:18.040 And in through the swinging what do you call those 0:14:18.240 --> 0:14:24.080 old timey western doors, swinging doors, swingy western doors. You 0:14:24.120 --> 0:14:27.280 hear the clink saloon doors, saloon doors. 0:14:27.320 --> 0:14:27.840 There you go. 0:14:28.360 --> 0:14:31.800 You hear the clink clink of spurs and in walks 0:14:32.320 --> 0:14:36.760 wearing a ten gallon hat, a B cell he says, 0:14:37.440 --> 0:14:42.280 I sure do, I sure do recognize that anigen. And 0:14:42.320 --> 0:14:47.520 then they get to work actually immunity. So ten gallon 0:14:47.560 --> 0:14:51.040 hat B cell. He knows what to do. He starts 0:14:51.080 --> 0:14:55.560 replicating and replicating, making more and more copies of himself, 0:14:55.600 --> 0:15:03.280 and inside he's making annibodies. These antibodies are super specific. 0:15:03.720 --> 0:15:07.160 They're going to target just that one antigen that the 0:15:07.200 --> 0:15:10.480 T cell brought over. And these B cells are making 0:15:10.840 --> 0:15:13.640 millions of these antibodies, and what they do is they 0:15:14.000 --> 0:15:17.680 throw them out into your bloodstream. They travel throughout your 0:15:17.720 --> 0:15:22.560 whole body, and they find and attached to that anigen 0:15:22.960 --> 0:15:26.000 anywhere that they find it, whether it's in your cells 0:15:26.280 --> 0:15:29.640 that have been infected, whether it's on the bacteria or 0:15:29.680 --> 0:15:32.320 on the outside of a virus. Anything that has this 0:15:32.440 --> 0:15:35.680 specific anigen is going to get an antibody attached to it. 0:15:35.680 --> 0:15:38.800 It's kind of like a flag that you put on 0:15:38.880 --> 0:15:41.480 buildings when you say this one's going to get demolished, 0:15:41.480 --> 0:15:43.680 and this one's going to get demolished. That's what an 0:15:43.680 --> 0:15:47.200 antibody is. So these antibodies go out and mark all 0:15:47.240 --> 0:15:50.560 of these cells so that the ensemble, the rest of 0:15:50.600 --> 0:15:53.000 the cast, the rest of your white blood cells can 0:15:53.040 --> 0:15:55.960 recognize it, and now they can come in and clean 0:15:56.000 --> 0:15:59.920 up the mess. They take soldiers exactly, so they come 0:16:00.240 --> 0:16:06.680 and destroy that infection, Okay, So can I just review absolutely? 0:16:07.080 --> 0:16:10.840 Okay. So the macrifhage picks something up weird and then 0:16:10.880 --> 0:16:14.640 they bring it over and they're like, okay, everyone, T cells, 0:16:15.320 --> 0:16:19.560 B cells, what is this? Mm hmmm. So the T cells, 0:16:20.120 --> 0:16:23.080 the killer ones, they go and they just kill anything 0:16:23.120 --> 0:16:25.680 that remotely resembles that antigen. 0:16:25.360 --> 0:16:27.720 Anything that specifically resembles that antigen. 0:16:28.280 --> 0:16:33.800 Okay, specifically resembles that antigen. What does that mean specifically resembles. 0:16:33.360 --> 0:16:36.440 It means anything that is that exact same antigen. So 0:16:36.560 --> 0:16:38.520 it's not going to go out and just kill anything 0:16:38.520 --> 0:16:39.800 that looks similar to it. 0:16:39.800 --> 0:16:43.840 It'll just okay that exact antigen, okay. And then the 0:16:44.040 --> 0:16:46.720 helper T cells they go and find the B cells 0:16:46.760 --> 0:16:49.600 and say, hey, this is what we're looking for. Can 0:16:49.680 --> 0:16:52.960 you go and tag everything exact? So then that makes 0:16:53.080 --> 0:16:56.960 the killer T cells job easier absolutely yeah, RCT. 0:16:57.000 --> 0:16:58.760 And it also brings in the rest of the white 0:16:58.760 --> 0:17:00.840 blood cells so that it's not just the T cells 0:17:00.840 --> 0:17:01.880 out there killing things. 0:17:02.280 --> 0:17:05.640 Okay. Act four memory. 0:17:06.800 --> 0:17:09.199 So once your body has done all this work and 0:17:09.240 --> 0:17:12.920 cleared the infection, it's not done. Old ten gallon hat 0:17:12.960 --> 0:17:16.280 B cell and a few of those wild cytotoxic mohawk 0:17:16.359 --> 0:17:21.359 T cells. They're going to develop into memory cells. These 0:17:21.359 --> 0:17:25.240 cells hang out and persist. They no longer run around 0:17:25.280 --> 0:17:28.880 making antibodies or killing cells. They're going to go backstage 0:17:29.440 --> 0:17:32.800 and wait until it's their time again. Maybe they'll play cards, 0:17:32.800 --> 0:17:37.200 they'll bide their time, and if that same antigen ever 0:17:37.640 --> 0:17:41.879 shows their face again, these B cells and T cells, 0:17:41.920 --> 0:17:45.359 the memory cells will be able to jump right back 0:17:45.440 --> 0:17:47.880 into action. They won't have to go through the whole 0:17:47.920 --> 0:17:51.520 rigamarole of acts one, two, and three. They'll just be 0:17:51.600 --> 0:17:54.280 able to use the antibodies they've already have in the 0:17:54.320 --> 0:17:59.560 memory cells to make more copies and identify and target 0:17:59.560 --> 0:18:03.359 that anergy and quash the infection before it ever takes hold. 0:18:04.880 --> 0:18:10.400 So this is the principle that vaccines exploit. They expose 0:18:10.440 --> 0:18:13.000 you to an anigen, which is a virus or a 0:18:13.000 --> 0:18:17.120 bacteria or part of a virus or bacteria, and that 0:18:17.200 --> 0:18:22.240 triggers your immune system to develop this memory response, so 0:18:22.320 --> 0:18:25.399 that if you're ever exposed to that virus or bacteria 0:18:25.480 --> 0:18:28.719 in real life, you've already got a response ready to go. 0:18:28.760 --> 0:18:30.760 You don't have to take the time to build that 0:18:30.800 --> 0:18:31.680 immune response. 0:18:32.400 --> 0:18:37.320 And so the difference between that first exposure and then 0:18:37.640 --> 0:18:40.960 seeing that same pathogen again is a state of disease, 0:18:41.080 --> 0:18:43.080 and then a state of rapid immune response and no 0:18:43.160 --> 0:18:47.200 disease exactly, and then a vaccine just bypasses that whole disease. 0:18:47.359 --> 0:18:51.600 You don't have to actually endure the disease symptoms exactly. 0:18:51.680 --> 0:18:56.280 So if you imagine that your immune cells, in a 0:18:56.320 --> 0:18:59.360 lot of cases, if they're dealing with a live virus, 0:18:59.400 --> 0:19:03.200 a full law on, fully loaded measles virus, it's not 0:19:03.240 --> 0:19:06.000 like they're just dealing with something passive. That virus has 0:19:06.040 --> 0:19:09.919 come in guns ablazing, it's replicating, it's going full force, 0:19:10.440 --> 0:19:13.720 while your immune cells might be kind of like tripping 0:19:13.720 --> 0:19:16.680 over their lines and getting things wrong and trying. 0:19:16.520 --> 0:19:18.080 To figure out what to do about it. 0:19:18.520 --> 0:19:22.879 Right, So, an immunization is kind of like a dress 0:19:22.920 --> 0:19:26.119 rehearsal for the play. It's real, there's people in the 0:19:26.160 --> 0:19:29.840 audience still, and you're going to develop the exact same 0:19:30.040 --> 0:19:32.560 response at the end of it, but you don't have 0:19:32.800 --> 0:19:37.320 a live virus trying to kill you while you develop 0:19:37.400 --> 0:19:39.400 this immune response the very first time. 0:19:40.160 --> 0:19:46.600 Mm hmmm, cool, yeah, cool, it's fantastic. I mean, vaccines 0:19:46.600 --> 0:19:48.520 are the best, You're the best, So. 0:19:48.840 --> 0:19:53.520 That's how vaccination can protect you as an individual. How 0:19:53.520 --> 0:19:56.800 does it protect an entire population. This is something we've 0:19:56.840 --> 0:20:02.400 touched on before, but it's called immunity, and it goes 0:20:02.440 --> 0:20:09.800 something like this. Every infectious agent bacteria, virus, fungi, whatever, 0:20:10.880 --> 0:20:14.440 in order to survive, it has to spread from person 0:20:14.640 --> 0:20:18.879 to person. That's how they reproduce. And in order to 0:20:18.960 --> 0:20:21.440 do so, in order to spread from person to person, 0:20:21.960 --> 0:20:26.879 there have to be susceptible people in the population for 0:20:27.040 --> 0:20:32.399 that virus or bacteria to get into. So if a 0:20:32.440 --> 0:20:35.679 population has a high level of vaccination, let's say like 0:20:35.920 --> 0:20:40.840 ninety seven percent of one hundred people are vaccinated, that 0:20:40.880 --> 0:20:44.360 means that those ninety seven people have developed this immune 0:20:44.359 --> 0:20:49.159 response already. They're already protected. So if you happen to 0:20:49.240 --> 0:20:52.320 drop an infected person in the middle of that population, 0:20:53.359 --> 0:20:57.440 the chances that that infected person would run into somebody 0:20:57.680 --> 0:21:01.960 who's still susceptible to that disease are really, really low. 0:21:02.960 --> 0:21:05.840 So you'd have that one infected person who will get 0:21:05.880 --> 0:21:09.600 sick and then hopefully they'll recover or else they'll die 0:21:09.760 --> 0:21:13.440 from their infection, and then that's it. Nobody else gets 0:21:13.440 --> 0:21:17.200 sick because that sick person didn't run into anyone who 0:21:17.280 --> 0:21:21.800 was susceptible to that disease. But if you imagine that 0:21:21.880 --> 0:21:25.400 maybe only fifty percent of people are vaccinated, then only 0:21:25.480 --> 0:21:28.480 fifty percent of people are immune and the other. 0:21:28.520 --> 0:21:30.040 Fifty are susceptible. 0:21:30.800 --> 0:21:32.960 And you dropped an infected individual in the middle of 0:21:33.040 --> 0:21:36.280 that population, there's a pretty good chance that that infected 0:21:36.320 --> 0:21:39.400 person will run into somebody who happens to be susceptible, 0:21:40.480 --> 0:21:42.879 and maybe they cough, or they shake their hand or 0:21:42.920 --> 0:21:45.840 lick their face, and now you have two infected people. 0:21:47.080 --> 0:21:50.160 And then that second infected person, they have a pretty 0:21:50.200 --> 0:21:54.320 good shot, like forty nine more people that they might 0:21:54.400 --> 0:21:58.679 run into another susceptible individual and lick their face, and 0:21:58.720 --> 0:22:02.720 now you have three infected individuals, right, and so on 0:22:02.840 --> 0:22:06.040 and so on. So this is the principle behind herd immunity. 0:22:06.080 --> 0:22:10.520 If the entire herd, the entire population, or enough of 0:22:10.560 --> 0:22:14.400 it is immune to infection, either because they've already been 0:22:14.440 --> 0:22:18.920 exposed and recovered from the disease or they were vaccinated 0:22:18.960 --> 0:22:22.719 and they developed immunity, then the infection can't spread. 0:22:23.680 --> 0:22:27.560 Right. So the more people that are immunized against something 0:22:27.760 --> 0:22:32.040 or immune to something by whatever means, the less chance 0:22:32.400 --> 0:22:35.520 that a pathogen has of establishing in a population or 0:22:35.520 --> 0:22:36.920 being transmitted exactly. 0:22:36.960 --> 0:22:40.920 So by getting vaccinated, you are protecting yourself from getting 0:22:40.960 --> 0:22:43.639 that infection, but you're also protecting that tiny baby on 0:22:43.680 --> 0:22:46.800 the train who's too young to get vaccinated, your grandma 0:22:46.840 --> 0:22:51.879 who's frail and immunocompromised, whoever. You're protecting literally everyone around 0:22:51.920 --> 0:22:57.720 you when you get vaccinated. So that's how vaccines work. 0:22:58.200 --> 0:23:02.000 They're pretty dang cool. Yeah, I love them, big fan, 0:23:02.400 --> 0:23:07.880 me too, major if you can't tell already. So, there 0:23:09.000 --> 0:23:11.680 are a lot of different types of vaccines, and we're 0:23:11.680 --> 0:23:15.120 going to talk a little bit about the differences between them. 0:23:15.240 --> 0:23:19.080 Not a full on immunology lecture, but just a quick rundown. 0:23:19.440 --> 0:23:20.240 But I do want to. 0:23:20.200 --> 0:23:23.320 Say at the very top of this that all vaccines 0:23:23.480 --> 0:23:29.000 that are used are extremely safe. They're extensively tested and 0:23:29.200 --> 0:23:32.960 very highly regulated, and all the different types of vaccines 0:23:33.000 --> 0:23:36.560 that we have are very effective. And part of the 0:23:36.600 --> 0:23:39.600 reason that we have different types of vaccines is because 0:23:40.119 --> 0:23:43.320 different viruses and bacteria behave differently, and so we have 0:23:43.359 --> 0:23:45.600 to come up with different types of vaccines to target 0:23:45.720 --> 0:23:51.040 those specific pathogens. So some vaccines, for example, the MMR 0:23:51.119 --> 0:23:54.840 vaccine that's measles, mumps, and rubella, which you've talked about before, 0:23:55.200 --> 0:23:59.080 and also varistella, which is chicken pox. These are made 0:23:59.119 --> 0:24:03.159 from what we call live I've attenuated viruses, so that 0:24:03.240 --> 0:24:06.160 means the vaccine itself has a live virus in it, 0:24:06.720 --> 0:24:10.080 but that virus has been modified so that it's super 0:24:10.200 --> 0:24:14.560 super weak. It's not a strong, virulent virus that actually 0:24:14.600 --> 0:24:19.680 makes you get sick. It's a weak, little, infantile virus. 0:24:20.760 --> 0:24:24.679 So this type of vaccine elicits a really good immune 0:24:24.720 --> 0:24:27.560 response because it's just like getting a real infection in 0:24:27.640 --> 0:24:32.520 that you have virus replicating in your body, but because 0:24:32.520 --> 0:24:36.360 it's such a weak virus, you don't get sick from it. However, 0:24:36.480 --> 0:24:39.600 it does mean that some people who are immuno compromised, 0:24:39.720 --> 0:24:42.560 who have very weak immune systems, might not be able 0:24:42.600 --> 0:24:45.560 to get these live virus vaccines because their immune system 0:24:45.640 --> 0:24:47.919 might not be strong enough to fight off even a 0:24:48.080 --> 0:24:49.320 very weak virus. 0:24:50.080 --> 0:24:51.480 Gotcha, Okay. 0:24:52.480 --> 0:24:56.879 We also have whole killed vaccines, So these are vaccines 0:24:56.880 --> 0:24:58.919 that are a whole entire virus, so all of the 0:24:58.920 --> 0:25:02.240 different parts of the virus, but we kill the virus 0:25:02.320 --> 0:25:04.320 before we make the vaccine out of it, so that's 0:25:04.359 --> 0:25:08.760 the inactivated poliovirus, the one that is an injection or 0:25:08.880 --> 0:25:10.760 the influenza vaccine. 0:25:10.920 --> 0:25:14.000 And so are there also killed bacteria vaccine? Are Yeah? 0:25:14.040 --> 0:25:16.720 So there's a killed bacteria vaccine for typhoid, and there's 0:25:16.760 --> 0:25:18.800 also a live vaccine for typhoid. 0:25:19.280 --> 0:25:20.560 Hey, there's both. 0:25:20.600 --> 0:25:25.919 Cool. So these whole killed vaccines, you still develop a 0:25:25.960 --> 0:25:28.760 really strong immune response, but you might need to get 0:25:28.800 --> 0:25:31.440 more boosters with this type of vaccine because it might 0:25:31.480 --> 0:25:33.800 not be quite as strong of a response as you 0:25:33.840 --> 0:25:38.080 get from a live vaccine. But people who are immuno 0:25:38.119 --> 0:25:41.600 compromised can still get these killed virus vaccines because there's 0:25:41.640 --> 0:25:44.520 no live virus in these vaccines that's replicating. 0:25:45.280 --> 0:25:49.520 So going back to the flu vaccine, Yes, this means 0:25:49.880 --> 0:25:50.880 this winds. 0:25:52.160 --> 0:25:55.280 That you cannot get the flu from the flu vaccine. 0:25:55.920 --> 0:26:00.760