WEBVTT - How Do Vaccines Prevent Diseases? 0:00:01.840 --> 0:00:07.960 Welcome to brainstud a production of iHeartRadio, Hey Brainstuff Lauren 0:00:08.000 --> 0:00:13.680 vogelbaumb Here. We may not have flying cars or hoverboards yet, 0:00:14.080 --> 0:00:17.560 but in some ways we truly live in the incredible future. 0:00:18.440 --> 0:00:21.080 For a trip or two to a healthcare professional and 0:00:21.120 --> 0:00:23.720 a nominal amount of money, if any out of pocket, 0:00:24.239 --> 0:00:29.000 we can prevent ourselves from getting sick. Vaccines are considered 0:00:29.160 --> 0:00:33.000 the most successful medical advancement in the history of public health. 0:00:33.800 --> 0:00:38.640 Before vaccinations, diseases like smallpox, polio, and rebella killed or 0:00:38.800 --> 0:00:43.800 paralyzed or caused serious birth defects regularly. These losses of 0:00:43.880 --> 0:00:48.040 life and types of suffering are now preventable with extremely 0:00:48.120 --> 0:00:51.720 small risk. A person born in the United States in 0:00:51.720 --> 0:00:54.880 the year nineteen hundred had an average life expectancy of 0:00:54.880 --> 0:00:58.320 forty seven years. As of twenty ten, it was seventy 0:00:58.360 --> 0:01:02.680 eight years. That's not because most adults never reached old 0:01:02.720 --> 0:01:06.639 age in the past. It's because babies and toddlers died 0:01:06.800 --> 0:01:10.240 way more often of diseases that we now vaccinate against. 0:01:11.520 --> 0:01:15.360 So today, let's talk about vaccines and the basic science 0:01:15.400 --> 0:01:18.880 behind how they prevent illness. We'll also go head to 0:01:18.920 --> 0:01:23.040 head with some of the common myths about vaccines. A 0:01:23.120 --> 0:01:26.000 Vaccines work based on the fact that once a person 0:01:26.040 --> 0:01:29.160 has caught a disease of some types, they'll probably be 0:01:29.240 --> 0:01:32.200 immune to that disease for the rest of their life. 0:01:32.480 --> 0:01:36.200 For example, once you've had chicken pox, it's extremely unlikely 0:01:36.280 --> 0:01:39.520 that you'll ever catch it again. This is because your 0:01:39.520 --> 0:01:43.319 body will recognize the disease and fight it off. This 0:01:43.440 --> 0:01:48.000 happens thanks to a process called the immune response. The 0:01:48.040 --> 0:01:50.840 beauty of vaccines is that they help your body develop 0:01:50.920 --> 0:01:54.400 these disease recognizing abilities without you needing to get sick 0:01:54.440 --> 0:01:58.400 in the first place. Here's how the immune response works. 0:01:59.240 --> 0:02:02.040 When a virus or or bacteria enters your body under 0:02:02.120 --> 0:02:05.600 normal circumstances, your immune system will identify it as a 0:02:05.600 --> 0:02:09.920 potential threat, recognizable because it has molecules on its surface 0:02:10.160 --> 0:02:15.080 called antigens. If your immune system identifies those antigens as 0:02:15.160 --> 0:02:18.920 being not from your own body and therefore potentially unsafe, 0:02:19.120 --> 0:02:23.320 it'll launch an attack. Your immune system attacks by developing 0:02:23.360 --> 0:02:27.680 invader specific proteins called antibodies that can destroy the antigen 0:02:27.800 --> 0:02:30.760 than anything attached to it, or tag it for destruction 0:02:30.919 --> 0:02:35.280 by immune system cells. After the battle, your immune system 0:02:35.360 --> 0:02:39.080 will stockpile that antibody and remember how to identify that 0:02:39.160 --> 0:02:44.560 antigen in most cases forever, so if your immune system 0:02:44.639 --> 0:02:47.720 encounters antigens of the same type later on, it can 0:02:47.720 --> 0:02:52.960 fight the disease off fast. Unfortunately, antibodies are really specific, 0:02:53.480 --> 0:02:56.520 so if you've had chicken pox, for example, that's great 0:02:56.520 --> 0:03:01.680 for preventing chicken pox, but useless against other diseases. When 0:03:01.760 --> 0:03:04.880 a disease infects a person, the germs that cause it 0:03:05.000 --> 0:03:08.800 multiply thousands and thousands of times until a raging infection 0:03:08.919 --> 0:03:12.000 is underway, which can have all kinds of unpleasant or 0:03:12.160 --> 0:03:16.880 even deadly effects. A vaccine provides just enough antigens for 0:03:16.919 --> 0:03:19.840 the body to recognize them and complete the immune response 0:03:19.919 --> 0:03:25.200 process without causing an infection. Vaccines are able to provide 0:03:25.240 --> 0:03:29.280 that goldilock zone of just enough antigens in two basic ways, 0:03:29.840 --> 0:03:35.800 through weakened germs or through inactivated germs. Vaccines that use 0:03:35.840 --> 0:03:41.320 weakened germs are also called live attenuated vaccines. Attenuated means weakened. 0:03:42.320 --> 0:03:45.120 When this type of vaccine is created, the virus or 0:03:45.160 --> 0:03:48.480 bacteria is weakened in a lab to the point where 0:03:48.480 --> 0:03:51.720 it's still kicking and able to reproduce, but it can't 0:03:51.720 --> 0:03:55.840 cause serious illness. It might reproduce a couple dozen times 0:03:55.920 --> 0:04:00.000 instead of thousands, but its presence is enough to cause 0:04:00.120 --> 0:04:05.520 and complete the body's immune response. Live attenuated vaccines can 0:04:05.600 --> 0:04:08.960 cause mild illness in some people, a low grade fever, 0:04:09.160 --> 0:04:12.640 a runny nose, or a few chicken pox spots, but 0:04:12.840 --> 0:04:16.120 it's maybe a day or two of discomfort, nothing compared 0:04:16.160 --> 0:04:20.359 to the full blown illness. To weaken the virus or bacteria, 0:04:20.800 --> 0:04:24.480 researchers take a specimen from an infected person. They then 0:04:24.560 --> 0:04:27.320 grow the germ in a test tube, a tissue culture, 0:04:27.480 --> 0:04:31.719 a chicken egg, or some other foreign host. They pass 0:04:31.839 --> 0:04:35.080 the germ into a second test tube or whatever, then 0:04:35.120 --> 0:04:38.359 a third, a fourth, and on and on. The measles 0:04:38.440 --> 0:04:43.280 virus was passed seventy seven times. Eventually, the germ gets 0:04:43.360 --> 0:04:46.280 so used to living in that comfortable test tube or 0:04:46.320 --> 0:04:49.840 other host environment that it loses its capacity to produce 0:04:49.880 --> 0:04:54.839 illness in living humans, but will still bear its identifying antigens. 0:04:56.040 --> 0:04:59.640 Examples of live attenuated vaccines are those for MMR, that is, 0:04:59.680 --> 0:05:03.440 the diesels mumps and rubella combo vaccine, chicken pox, and 0:05:03.480 --> 0:05:07.719 the entran nasal form of the flu vaccine. The other 0:05:07.800 --> 0:05:13.160 type of vaccines uses inactivated germs. In these, the virus 0:05:13.240 --> 0:05:18.000 or bacteria has been rendered completely ineffective or dead, although 0:05:18.040 --> 0:05:20.839 one could argue that viruses aren't really alive to begin with. 0:05:21.920 --> 0:05:26.839 Researchers accomplish this with compounds like formaldehyde or detergents, which 0:05:26.839 --> 0:05:31.719 are then separated out from the inactivated germs. Pieces of 0:05:31.720 --> 0:05:35.240 the germs, including their antigens, go into the vaccine, which 0:05:35.279 --> 0:05:38.440 can thus trigger the immune response with zero chance of 0:05:38.440 --> 0:05:43.200 an actual infection. Unfortunately, the strength of these vaccines tends 0:05:43.240 --> 0:05:46.880 to wear off over time, resulting in less long lasting immunity, 0:05:47.640 --> 0:05:51.279 so multiple doses of inactivated vaccines are usually necessary to 0:05:51.400 --> 0:05:56.080 provide the best protection. Examples of inactivated vaccines are those 0:05:56.120 --> 0:06:00.120 for heptitis A and B, polio, meningitis strip and and 0:06:00.160 --> 0:06:04.719 the injected form of the flu vaccine. Inactivated vaccines are 0:06:04.760 --> 0:06:09.240 preferable because they're safer, and most bacterial vaccines are this type, 0:06:09.880 --> 0:06:14.400 but viruses often require live, attenuated vaccines because that's the 0:06:14.440 --> 0:06:18.520 best we can do to fight them. There are some exceptions. 0:06:18.960 --> 0:06:22.120 For example, rabies is a virus that's too dangerous to 0:06:22.160 --> 0:06:24.719 give people in a week ined state because a Rabi's 0:06:24.760 --> 0:06:27.720 infection is always fatal in humans, so doctors don't want 0:06:27.760 --> 0:06:30.480 to take any risks. I'll have to do a whole 0:06:30.480 --> 0:06:33.200 other episode on how vaccines are developed because it's a 0:06:33.240 --> 0:06:37.200 big topic. But let's talk about what all goes into 0:06:37.279 --> 0:06:40.599 a vaccine other than the germ and or its antigen, 0:06:41.080 --> 0:06:45.520 which could be considered the active ingredient. Every vaccine is 0:06:45.640 --> 0:06:50.400 unique to the disease in question, but here's the gist. First, 0:06:50.640 --> 0:06:55.560 many vaccines contain what's called adjuvants, which are helpful substances 0:06:55.600 --> 0:07:00.160 that make the vaccine more effective. Very basically, adjuvants a 0:07:00.200 --> 0:07:02.839 felly poke at your immune system to make it react 0:07:02.880 --> 0:07:08.040 more strongly to the mild threat that the vaccine poses. Next, 0:07:08.160 --> 0:07:11.040 you've often got a stabilizer, which is a substance that 0:07:11.120 --> 0:07:14.840 helps protect the active ingredient as it's stored and transported 0:07:14.920 --> 0:07:20.440 in different temperatures and levels of jostle. Finally, when vials 0:07:20.440 --> 0:07:24.720 of a vaccine contain multiple doses, a preservative or disinfectant 0:07:24.880 --> 0:07:28.120 is required. This is so that every time a dose 0:07:28.200 --> 0:07:32.120 is removed by needle, any microbe that, against all odds, 0:07:32.200 --> 0:07:35.200 comes into the vial with that clean needle is killed 0:07:35.280 --> 0:07:37.680 in the vial and thus won't be able to cause 0:07:37.680 --> 0:07:40.200 an infection in the person receiving the next dose of 0:07:40.240 --> 0:07:44.880 the vaccine. All of these substances are thoroughly regulated to 0:07:45.000 --> 0:07:47.480 ensure their safety in the amounts in which they're used. 0:07:48.800 --> 0:07:52.000 Health experts recommend so many vaccines for babies and young 0:07:52.080 --> 0:07:57.240 children because they're more risk for serious infections. It's a 0:07:57.280 --> 0:08:00.800 little bit gruesome, but really important to under stand that 0:08:00.880 --> 0:08:04.160 the diseases that infants and children are vaccinated against today 0:08:04.520 --> 0:08:09.520 are truly horrifying. For example, diphtheria, a nose and throat 0:08:09.560 --> 0:08:13.280 infection that can cause difficulty breathing, heart failure, and paralysis 0:08:13.760 --> 0:08:17.160 once killed over fifteen thousand children a year in the 0:08:17.280 --> 0:08:22.080 US alone. Or take meningitis, an infection of the covering 0:08:22.160 --> 0:08:25.480 around the brain and the spinal cord. Survivors can face 0:08:25.560 --> 0:08:30.160 brain damage, deafness, and seizures. Polio once infected up to 0:08:30.160 --> 0:08:33.560 twenty thousand Americans a year, and survivors are often left 0:08:33.600 --> 0:08:36.280 paralyzed and dependent on mobility tools for the rest of 0:08:36.320 --> 0:08:40.760 their lives. Measles doesn't just cause a rash, it can 0:08:40.800 --> 0:08:45.200 cause brain swelling and even death. Mumps can cause deafness 0:08:45.200 --> 0:08:49.120 and brain damage, and rebella, which is often transmitted to 0:08:49.240 --> 0:08:53.840 unborn fetuses during pregnancy, can cause miscarriages or premature births, 0:08:54.160 --> 0:08:58.200 and birth defects in survivors. All of this is why 0:08:58.280 --> 0:09:01.280 researchers have spent so much time, time, and effort and 0:09:01.360 --> 0:09:06.800 money developing safe vaccines. Still, there's a lot of vaccine 0:09:06.840 --> 0:09:10.760 uncertainty out there right now, and a lot of concerns circulating, 0:09:11.440 --> 0:09:16.840 which is fair and healthy. Asking questions is good. So 0:09:17.120 --> 0:09:21.240 let's address a few of the common ones first. And 0:09:21.280 --> 0:09:24.360 the elephant in the room is the concern that vaccines 0:09:24.480 --> 0:09:29.480 might cause autism. This is, in essence, a lie that 0:09:29.640 --> 0:09:32.880 was manufactured starting the nineteen nineties by this guy named 0:09:32.920 --> 0:09:36.040 Andrew Wakefield, who was at that time a doctor. His 0:09:36.200 --> 0:09:40.080 license has since been revoked. He got a study published 0:09:40.080 --> 0:09:43.040 in the renowned medical journal The Landset in nineteen ninety 0:09:43.040 --> 0:09:47.559 eight that supposedly linked the MMR vaccine to autism in children, 0:09:48.760 --> 0:09:51.840 but when other doctors and researchers started looking at it, 0:09:52.040 --> 0:09:55.000 they realized that Wakefield study didn't prove that at all. 0:09:55.320 --> 0:09:58.000 He had cherry picked his cases and didn't show any 0:09:58.040 --> 0:10:02.600 real evidence. The Landset retracted the study and apologized for 0:10:02.679 --> 0:10:06.719 printing it in twenty ten, but due to publicity. The 0:10:06.760 --> 0:10:11.240 idea of the link still spread. The story even morphed 0:10:11.240 --> 0:10:15.319 from the supposed culprit being the MMR vaccine to thimerasol, 0:10:15.480 --> 0:10:20.040 which is a preservative that contains mercury. Lots and lots 0:10:20.080 --> 0:10:22.760 of further studies have been done that have shown no 0:10:22.960 --> 0:10:28.080 link between any vaccines and autism. Also, it later came 0:10:28.080 --> 0:10:31.079 out that Wakefield was poised to make tens of millions 0:10:31.120 --> 0:10:33.840 of dollars a year on this diagnostic test that he 0:10:33.880 --> 0:10:38.600 had patented based on his falsified link. The whole thing 0:10:38.640 --> 0:10:40.960 has been called one of the most serious frauds in 0:10:41.000 --> 0:10:45.000 medical history because it has made people feel less safe 0:10:45.080 --> 0:10:49.920 about saving their children from these terrible diseases. If it helps. 0:10:50.240 --> 0:10:53.520 Amid all of this concern, vaccine makers have stopped using 0:10:53.559 --> 0:10:57.520 thimerasol in just about all vaccines, just to reassure people 0:10:57.559 --> 0:11:02.199 that they're safe. Next step, let's talk about the concern 0:11:02.240 --> 0:11:06.040 that vaccines are unnecessary because those diseases are pretty much 0:11:06.080 --> 0:11:11.280 gone anyway. Unfortunately, the only vaccine preventable disease that's been 0:11:11.320 --> 0:11:15.880 completely wiped out is smallpox. Other diseases can still spread 0:11:15.880 --> 0:11:19.960 through things like international travel that take measles. For example, 0:11:20.400 --> 0:11:22.640 It was considered gone from the US as of the 0:11:22.720 --> 0:11:26.000 year two thousand, but as of September ninth, of twenty 0:11:26.000 --> 0:11:28.800 twenty five, there have been one thy four hundred and 0:11:28.840 --> 0:11:32.400 fifty four cases confirmed here this year, resulting in one 0:11:32.440 --> 0:11:37.040 hundred and eighty hospitalizations and three deaths. Any deaths from 0:11:37.080 --> 0:11:41.720 a preventable disease are too many. Another fair concern is 0:11:41.760 --> 0:11:45.120 that babies are too fragile that their immune system is 0:11:45.160 --> 0:11:48.600 going to get overwhelmed by receiving so many vaccinations at once. 0:11:50.000 --> 0:11:53.079 But babies get an immune workout all the time on 0:11:53.360 --> 0:11:57.679 play dates, at church, at the grocery store. Vaccines can't 0:11:57.760 --> 0:12:01.959 overwhelm a functional immune system, and you would know there 0:12:02.000 --> 0:12:04.480 would be signs or your health care provider would tell 0:12:04.520 --> 0:12:08.199 you if your kid was an exception. There are people 0:12:08.200 --> 0:12:11.440 who can't receive vaccines because of a weakened immune system, 0:12:11.840 --> 0:12:15.840 like some patients with cancer. That is part of why 0:12:15.880 --> 0:12:19.120 public health experts want healthy adolescents and adults to stay 0:12:19.200 --> 0:12:23.440 up to date on their immunizations too. Vaccines prevent healthy 0:12:23.440 --> 0:12:27.240 people from getting sick, which means, well, first off, we 0:12:27.320 --> 0:12:31.040 won't suffer the annoying to painful effects of illness, and 0:12:31.120 --> 0:12:34.559 we won't fall behind at home or at work. And 0:12:34.920 --> 0:12:37.520 second of all, if we don't get sick, we won't 0:12:37.559 --> 0:12:39.800 pass on an illness to someone more at risk for 0:12:39.920 --> 0:12:45.280 severe symptoms, including death. Getting vaccinated can save a life. 0:12:45.760 --> 0:12:48.280 It might be yours, it might be a loved ones. 0:12:49.160 --> 0:12:52.719 Insurance often covers them, and walking clinics often provide them 0:12:52.760 --> 0:12:57.559 for cheap Again, it's normal and good to have questions 0:12:57.679 --> 0:13:01.719 or concerns, and please talk to a healthcare provider if 0:13:01.760 --> 0:13:04.080 you do. After all, at the end of the day, 0:13:04.559 --> 0:13:11.760 I'm just a podcast host. Today's episode is based on 0:13:11.760 --> 0:13:14.880 the article how vaccines Work on HowStuffWorks dot com, written 0:13:14.920 --> 0:13:17.800 by Leah Hoy. Brain Stuff is production by Heart Radio 0:13:17.840 --> 0:13:20.240 in partnership with HowStuffWorks dot Com and is produced by 0:13:20.280 --> 0:13:23.520 Tyler Klang. For more podcasts from my heart Radio, visit 0:13:23.559 --> 0:13:26.600 the iHeartRadio app, Apple Podcasts, or wherever you listen to 0:13:26.640 --> 0:13:27.520 your favorite shows.