 Hey everybody, Dr. O here. In this video, we're going to talk about the different types of vaccines. So I covered what vaccines are and how they work in a different video. I'll have a couple of their shorter videos on vaccines, but I really want to hone in on the different types of vaccines that you'll see here. And just so you know, there's going to be all sorts of vaccines coming in the future. They won't make this list. This is going to be the current vaccines that are being used. So you see here, we're going to start with the first we're going to start with are the live attenuated vaccines versus the inactivated or killed vaccines. So terminology, the term attenuated means weakened. So these are living pathogenic organisms that have been weakened. So they weaken them with genetic manipulation, or a lot of times they just grow them in a culture they don't like until they just basically weaken and have decreased virulence. They're less scary organisms, but they are living organisms. So let's talk about the pros and cons of doing this. So number one, it more closely mimics an actual infection because you really are being infected. You're being infected with a weaker version of the organism. That means the organisms are alive when they go in. They're going to stay, stay alive while your body mounts an immune defense, which can take, you know, 10 to 14 days. We covered that in the other video. So you are going to get a more lifelong immunity. And as you can see here, so you see here, it says long lasting immunity. And right above that it says both cellular and humoral immunity. That means your T cells and your B cells have been made aware of this organism. And it's been around in your body long enough to actually confer really good immunity. So you're only going to need one dose instead of a series of doses. You're going to get both cellular and humoral immunity. And you're going to get a more longer lasting immunity. Now the other thing here is you can see another advantage is transmission to contacts. So you are infected. You can technically spread this to other people. But again, you're spreading a very weakened version of it. So the disadvantages is that this is a living organisms. So what makes it advantageous also makes it a disadvantage because there's always the risk. If you're an immunocompromised person, this infection would be enough to make you sick. You would never give this kind of vaccine to someone that's immunocompromised. There's also the resist that it can back mute the risk that it can back mutate into a more pathogenic version. So those are going to be the key disadvantages. So you don't see as many as you used to because there are those risks and there are people that can't take them. This is what we mean when we say that herd immunity is important because there are people that cannot be vaccinated for some diseases. If you're immunocompromised or too young or whatever, this kind of vaccine could potentially be dangerous. All right, that is a live attenuated or weakened vaccine. Next we have the inactivated whole agent vaccine. So it is the entire pathogen still, but it's been killed or inactivated. Usually radiation, heat or different chemicals will do this. So the pros, as you can see here, ease of storage and transport, you don't have to keep it refrigerated and it's just less likely to break down because you're not dealing with the living organism. It's already broken down. They're already dead. There's also no risk of infection. You're not actually infecting anyone. So you're just putting in these dead pieces. So these kind of vaccines, these killed agent vaccines can't be spread to other people. There's no risk for you getting the infection because you're just getting these dead organisms. But the downside, the problem is that the immunity is going to be weaker. So it's only going to be humoral immunity which is driven by your B cells instead of the cellular and humoral immunity. The other downside is it does say here higher doses and more boosters required. Now I'm a stickler for this just because I use the term booster a little differently. If you hear me talking about a booster shot, I'm talking about your toxoid vaccines. So what I would say here though is this takes a series of injections because when you inject someone with this, it's going to be out of the system very quickly. Whereas with a live attenuated vaccine, it's going to be in their body until your immune system mounts the response to get rid of it because of a living infection. So this is why it would take a series of injections for your inactivative vaccines. So real quick review because these are the two most important types currently. The live attenuated or weakened vaccines more powerful, only need the one shot better immunity. The downside is there is a risk of infection either if your immunocompromised or if it back mutates and reverts to a more dangerous strain. The inactivated, the killed vaccines takes a series of injections. You're not going to get as good of immunity but it is much safer and people that are immunocompromised can take them. So that's your live attenuated vaccines versus your inactivative vaccines. Next ones we won't spend here as much time on. So here you see the subunit vaccines, the toxoid vaccines and the conjugate vaccines all very important. You're seeing a lot more of these now where instead of giving a living or dead whole organism you're given pieces. So with the immune system I always think about wanted posters. So with the other two you're actually giving someone a wanted poster with the entire picture on it. So this is the criminal to look out for. With subunit vaccines it's just pieces. So imagine if you had a picture of me, all you have was my hair and my eyes and my ears and my goatee and a couple more features, this little scar here. You wouldn't have the entire picture but you'd have enough of me to recognize that I shouldn't be there and to mount immune response and get rid of me. So you're using pieces instead of the entire organism. So you're never given an entire organism so there's no risk of infection but also because you're not given a living organism it's going to take multiple doses in order to get the full effect. Different types of these subunit vaccines, recombinant vaccines would be ones that are subunit vaccines that have been created by genetic modification. I also would put the virus-like particles in this group. I'm pretty fascinated by these. A virus-like particle looks like the entire virus on the outside but there's no payload on the inside so you can't, so you teach your immune system what a virus looks like but there's no risk of it actually causing an infection. All right so that is your subunit vaccines. Next we have the toxoids and then we'll talk about the conjugate vaccines before we're done here. So toxoids are a special kind of vaccine because they're not a vaccine against an organism. They're a vaccine against the toxins that organisms produced. So like it says here, an inactivated bacterial toxin so your immune system will recognize the toxin and be able to deal with it when it shows up. As you can see here it's only humoral immunity from your B cells that's totally fine. That's what would deal with toxins anyways. This vaccine though is not actually trying to kill the organism. You see here the examples, botulism, diphtheria, pertussis, tetanus. So let's think like tetanus for example. If you get a tetanus shot it is not a vaccine that's trying to kill or control clostridium tetanus, the organism that causes tetanus. It's inactivating the toxins as they're being produced. So that's what a toxoid is, a vaccine against toxins instead of against organisms. So one more important thing for me to note, if you're one of my students, this is what I call the booster shots. The booster shots are the every 10 years revaccination you need with these toxoids. That's how I personally use the term boosters. I just talk about series of injections, series of doses or multiple doses in other contexts. So I'm not saying I'm right or anyone else is wrong. It's just how terms are somehow used differently. And then lastly we have conjugate vaccines. So specifically conjugate vaccines are designed to help children. So children have a harder time becoming immune to, with vaccines that only go after the capsule of these organisms, these polysaccharide or carbohydrate based vaccines. So what a conjugate vaccine does is it adds proteins to it, which allows for that better response in kids. So these are very important vaccines. But an adult certainly can take them and do take them. Like streptococcus pneumonia, the pneumovax is a good example of a conjugate vaccine. But the key thing I want you to know about them is that conjugate vaccines protect children in ways other vaccines may not be able to. All right, so those are all the major classes and types of vaccines. I hope this helped. Have a wonderful day. Be blessed.