 Yeah, everybody. Dr. O here. I want to talk about vaccines in this video. So I'm primarily going to focus on what they are and how they work, but I also want to talk about really what they are, but also a little bit of what they're not. I will talk about why you might feel sick after getting a vaccine. I also want to talk about why vaccines are their own worst enemy. And that's mainly because of we don't think as much about the alternative to vaccination. We primarily think about vaccines potentially being harmful, but not the alternatives. So let's just dive in with the terminology and the basics of how vaccines work before we get into some of that more complicated stuff. So here's the definition of a vaccine. It is a suspension of organisms or fractions, parts of organisms that induce immunity. So let's do a real quick primer on the immune system in case you haven't taken anatomy class that covers this in depth. So this is normally what happens. So you see an initial exposure on the left and then you have the primary immune response. Well, the primary immune response takes a long time. It can take 10 to 14 days. And as you can see from this little graph, it's pretty weak. Secondary exposure. So now that you're immune to something, so let's say you actually were exposed to a disease and that first prime, the immune exposure is pretty weak. The second time you're exposed to something, the immune response is much quicker and much more powerful. So this is why the first time you're exposed to a pathogen out in nature, out in the wild, you get sick because the pathogen has free rain in your body for days before you mount a complete immune response. Then the next time you see it, you should be immune. Now that's assuming that you survived, right? And that's the scary thing about some of these diseases is that initial exposure might actually kill you because your immune system is not prepared for it. So what vaccines do is the initial exposure is kind of a quote unquote fake exposure. And I covered the types of vaccines in a different video as far as whether it's a weakened organism or a killed organism or just pieces of organisms. But your first exposure, instead of it actually being exposed to the measles and taking your chances with that virus, was the MMR vaccine or some way to get you the measles vaccine. So the first exposure wouldn't lead to illness, but it would lead to your immune system recognizing something. So here's the best way that I describe it to people is that vaccines work so that the first time you're actually exposed to a pathogen, the real organism out in the world is the second time your immune system has seen it. And that's why this chart is so important because that means the first time you're actually exposed to something, you're going to get a quicker, more powerful immune response and you shouldn't get sick. So you basically get the benefits of immunity without having to have gone through the disease the first time. So I know I bring this up in multiple videos, but this idea to me of these wanted postures is the key to me, right? The first time you see a murderer or a bank robber, you don't want them standing in front of you. You want to see a wanted poster. So the measles, would you rather see them, you know, the measles coming at you when you're not immune to it, or would you rather see a wanted poster with the measles on it? So your immune system has seen it, is prepared for it, knows that it might be coming. And if it shows up, they pounce on it and wipe it out. So that's kind of how I like to think of vaccines. So they bypass the need to get sick while your immune system is recognizing that something is there. So that way, that's how they work. All right. So that's the benefits of vaccines and at least how they work, right? Getting immune to something without having to take the chances of dying from the disease in the process. That's pretty cool. Why do you feel sick? This is a very commonly asked question to me teaching microbiology about vaccines is, do vaccines make you sick, right? Do vaccines give you the disease? I got the flu shot and then I felt like crap or this or that. Well, so why do you feel sick after getting a vaccine? It's your immune system because your immune system is still going to mount this response. There's still going to be inflammation. There's still going to potentially be fever. There's still going to be localized reactions by the injection side, these types of things. But your immune system saw something and is mounting a response to it. So what you're feeling is the immune system pouncing on that vaccine like it would have an invader. But the good benefit is the vaccine isn't fighting back the same way that measles or rubella or any other ones would. All right. One of their cool thing about vaccines, as we're talking about how vaccines work, I just explained how vaccines work for an individual, but they also work for a community as long as you reach this herd immunity. So I just another picture of a vaccine here while we talk about this, but like who do vaccines protect? So vaccines protect you if you got the vaccine. And of course, if the vaccine actually took hold, right? No vaccine is 100% effective, which means some people were vaccinated and not protected. Now some diseases are or some vaccines are almost 100%. Others are quite a bit lower and it has to do with your immune system and other things. But so vaccines protect you if you got them and they were effective. But they also protect the community as a whole if we reach this herd immunity. Now I always say that 85% is a good starting point for herd immunity. But for some or for some diseases, it does have to be higher than that. It really depends on how contagious the disease is. And how easily it spreads. Like to reach herd immunity from measles, you might be looking at needing 97% of the population to be immune to it. But so what herd immunity does and I did a separate video on herd immunity, but herd immunity creates barriers to the spread of infection. So if I'm not protected, and someone over there isn't protected, if everyone between us is those people are become a barrier that protects me. So my environment can be full of barriers to the spread of disease or carriers of the disease. And that's what herd immunity is. So vaccines protect you, but they also protect the people around you. And then hopefully people around you getting vaccinated protects you as well. One more thing about who vaccines protect that's the idea of maternal vaccines. So if if mom gets certain vaccines, it can actually like pertussis would be a good example. If if mom's immune to it, then mom will be protecting the baby the first few months of their lives, especially if their breastfeeding and those antibodies are being passed into breast breast milk. So so moms can protect their children, people can protect themselves and then the community can protect itself as a group if you think about herd immunity. So are they safe? I won't go into all the vaccine safety stuff right here. I'm sure I'll tackle that topic at some point in the future. But here's what I always say in class, right? There's no vaccine with a therapeutic risk index of zero. But vaccines are much safer than the diseases they prevent. And they're also safer than some of the old alternatives that I'll get to in just a second. So so what do I mean by that, right? So there there's no vaccine that never has any adverse effects. It appears that about one in a million kids do have a serious adverse effect. But you know, a lot of the other ones have been have been refuted quite a bit. But let me show you just just I have I put together some numbers here. So let's say it's true that one in a million kids even one in many kids died now and I would hate for that to happen, right? I hate anytime any kid has any disease. But the CDC estimates that the vaccination program in the US alone prevents 2.1 million hospitalizations and 73,200 deaths every year. That's just the US vaccination program. And let's look at like what happens when these vaccination programs don't work or prior to having them. So after smallpox was eradicated in the late 70s, the leading cause of childhood death was measles. It still killed 2.6 million kids a year. See, we're not we're not afraid of these diseases. The reason people aren't as concerned about getting vaccines. We're not afraid of these diseases. We're just not scared of them like we should be because vaccines work, right? You don't you don't hear about 2.6 million kids dying every year with the measles. So you don't you wonder if the vaccine is necessary. So that's why I was like to say they're their own worst enemy. Another example closer to home. So there was that there was a dip in vaccine uses and usage in the 60s. And then in 1964 1965, there was a rubella outbreak. I'm 12.5 million people got infected. 11,000 pregnant women lost their babies either because of a spontaneous abortion or actually having one because the because of the problems with the child. 2000 over 2000 newborn babies died and then 20,000 babies had congenital rubella syndrome. I actually know two people that are deaf or hearing impaired because of the congenital rubella syndrome they got at this time period. So so again our vaccines 100% safe. No, I would never say that, but the diseases they protect us from are super, super terrifying. Let's see, like your your your DPT, your DTAP vaccines, right? So you're just your your your diphtheria and tetanus vaccines alone, they believe have saved 60 million lives. So even if you look at the worst case scenario and say that vaccines do hurt a percentage of people, even if vaccines did all the things that you know that people say they do potentially with a lot of misinformation that's out there, we're still looking at a positive trade-off and I hate to have to look at it that way, but I think it's very important to understand that even if vaccines were as bad as some people want you to believe, they're protecting us from a situation that would be much much worse. So all right, and then lastly I said earlier that they're they're they're safer than the than the alternative treatments used to be. So here not a lot of good pictures, but from the second century, right? But this is an example of variolation. So prior to vaccination, prior to Edward Jenner and the and using cowpox to prevent smallpox, variolation was actually so they would either this kid is probably in it's a you know just an image, but this kid's probably inhaling ground up scabs from someone that had smallpox. Another way to variolate would have been to take some of the pus from someone's smallpox lesions and scrape it into your skin. So variolation was actually exposing you to small amounts in the organism and hoping you get the immune response without without getting the full on disease. So I think that some evidence says they've been doing this since the second century BC, but for sure the 10th century by then for sure in a starter travel around the world. So variolation think about the you know the fear of being a parent and deciding what you should do with vaccines. Well, the same thing happened back then. Someone would come to you and say, I'm going to do it. I don't if they use these numbers or anything, but I'm going to come in and try I'm going to do this procedure that has a you know variolation had about a 1% mortality rate. So let's say so I'm going to do a procedure that has a 1% chance of killing your child, but if they don't die, they will be protected from smallpox, which if they get smallpox in the wild, there's a 50% chance of dying, but that's a big if right if they get it. So these tough decisions have been have been made in the past as well. So all right, so that is how vaccines work, what they do, you know what they don't do a little bit about vaccine safety and then then variolation here this alternative. So I hope this gives you a lot of good information. I know the vaccines are a very difficult concept, but I think it's very important to have real conversations about this and help people understand the benefits of vaccination. Okay, I do hope this helps. Have a wonderful day. Be blessed.